Elon 100 documents

Brochures, specifications, installation manuals, and troubleshooting guides.

Brochures

Brochures

PowerOptimal Elon 100 - how to maximise your savings

How can you Maximise Your Savings with the Elon 100 Solar PV Water Heater?

The Elon 100® solar PV water heater will help you save money on the biggest single electricity user in your household: your geyser.

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Here are some tips for maximising your savings:

However, the "SOLAR ONLY" setting will only be feasible if you have enough solar PV modules for your household’s level of hot water use. Even if you have a smaller system, you might be able to run it on “SOLAR ONLY” for most of the year, depending on your location.

See this video for more on how to use the Elon 100 solar PV water heater.

Brochures

PowerOptimal Elon® 100 brochure V2.13

V2.13

The PowerOptimal Elon® The Most Cost-Effective Solar Water Heating Solution

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Conventional wisdom has it that solar thermal is the most cost-effective solar water heating solution. Well, it is time to update conventional wisdom! The innovative and patent-pending PowerOptimal Elon® breaks the mould in bringing solar PV (photovoltaic) and water heating together in the most cost-effective package ever. Meeting national building regulations on water heating is now made easy with the PowerOptimal Elon®.

With competitive capital cost, very long lifetimes and almost non-existent maintenance, this is the lowest cost per kWh of water heating your money can buy anywhere.

HOW IT WORKS

The Elon® uses advanced proprietary switching technology to allow for direct provision of DC (Direct Current) power from solar PV (photovoltaic) modules to electric geyser and optimised solar power use in a single compact unit. The system can be connected to the grid (AC mains) as well, and intelligently switches between AC and solar power supply. The system requires no inverter and no battery, and can be connected to standard AC geyser heating elements and AC thermostats, which translates into the most cost-effective solar water heating option today.

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WHAT ARE THE BENEFITS?

Based on a lifetime cost per kWh of water heating (Levelised Cost of Energy or LCOE), the Elon® brings you the lowest cost of any water heating option in South Africa at about R1.15/kWh. The average residential price of electricity in South Africa in 2024 (based on a middle-class household in the four largest metropolitan areas) is about R3.12/kWh and increases every year. Reduce your exposure to ever-increasing electricity prices by installing an Elon® system.

A graph of water heating costs Description automatically generated

There are many other benefits to the PowerOptimal Elon® solar PV water heating system:

  • No tank on the roof
  • Easy installation - no plumbing changes for retrofit
  • You can use your existing electric geyser
  • No noise (unlike heat pumps or solar geysers with circulation pumps)
  • Lower weight of rooftop components compared to solar geysers means easier installation
  • Much longer life and lower maintenance than solar thermal or heat pump systems
  • Intelligent grid power backup means you won’t have cold water even when there is no sun, whilst grid power use is minimised
  • Excellent option for meeting SANS 10400-XA energy efficiency requirements
  • Hot water during power failures
  • The patent-pending AC-DC switching technology is the smallest and lowest cost solar DC switching solution on the market
  • Less vandal-prone than solar geyser systems
  • Patent-pending solar power availability detection technology means that no photocell is required compared to solar PV-inverter systems
  • Delivers power to loads at lower voltage than what is possible with inverters (from just 20V under load)
  • Control dial gives full control over operation – from mains power only to solar power only

WHAT DOES THE SAVINGS TRANSLATE TO IN PRACTICAL TERMS?

Below is a comparison of the energy cost per shower for various energy supply options.

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WHO IS POWEROPTIMAL?

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PowerOptimal is an award-winning company with a mission to bring affordable, reliable and sustainable energy solutions to households and businesses across the African continent. The company is built on proven South African electricity demand management technology, with a strong track record of successful installations over more than 10 years.

FAQ – Frequently Asked Questions

How can solar PV water heating be more cost-effective than solar thermal? Isn’t solar thermal efficiency much better than solar PV?

It is true that solar thermal collectors are currently more efficient per square meter (area) than solar PV modules in collecting solar energy. However, overall efficiency must also take into consideration factors such as heat loss in piping (especially in winter) and energy use of solar thermal circulation pumps.

Solar thermal system lifetimes range from about 7 years (for cheap imports) to about 15 years for high quality (and more expensive) systems. (In a comprehensive analysis, Sandia National Laboratories found that about 50% of solar thermal systems fail within a 10-year period.) Solar PV modules are routinely guaranteed at 80% performance after 25 years, and the US National Renewable Energy Laboratory uses a lifetime of 33 years in its solar PV system calculations.

Solar PV module costs have dropped dramatically – by over 80% in the past 5 years – and the trend is continuing. This has changed the paradigm. Whilst solar PV systems will continue to require more roof space than solar thermal in the short term, the key issue is not roof space, but cost. Solar PV systems have become cost-competitive to solar thermal, and the much longer lifetimes and lower maintenance translate into a lower lifetime cost per kWh.

What is SANS 10400-XA?

It is a set of energy efficiency regulations that are compulsory for new buildings and for additions and extensions to existing buildings. One of the key requirements of SANS 10400-XA is that no more than 50% of the annual volume of domestic hot water must be heated using grid electricity.

The PowerOptimal Elon® makes meeting this requirement easier than ever before, providing a new cost-effective alternative to heat pump and solar thermal systems.

Do I need to change the heating element on my existing geyser to install a PowerOptimal Elon® system?

Not necessarily. PowerOptimal Elon® works with existing standard AC heater elements, but the best element size (power rating) depends on the size of your solar PV array. If you are building a new house, you can just specify the right heater element from the start. Refer to the table on the next page for a guide or ask the PowerOptimal agent or your installer about the best module & element matching configuration for your needs.

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Where can I buy an Elon® system?

For installers and resellers: Kwikot (part of Electrolux South Africa) is the sole distributor of the PowerOptimal Elon® in South Africa. Contact the PowerOptimal team for assistance with buying.

For residential customers: Contact PowerOptimal to get a referral to one of our preferred installers depending on your location.

How many solar modules do I need?

The most important factor here is the total size or power of the solar PV array (measured in kilowatt or kWp) rather than the number of modules. The size of solar PV array required depends on the number of people in the household and your hot water usage levels. A minimum of 1 kWp is recommended. Below is an easy selection guide. Refer to the PowerOptimal Elon® 100 Technical Specifications or the full selection guide (available on the downloads page) for a more detailed guide.

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* 6-minute showers at 40 ºC with 8 litre/min (low-flow) showerheads

What is the payback period for an Elon® system?

This depends on your current electricity tariff, how many solar modules you install, your hot water use, and electricity price increases in the next few years, but typically payback period is in the range of 2½ to 5 years. With a typical solar module life expectancy of more than 30 years, this means that you will enjoy at least 25 years of free hot water!

Where can I learn more about the PowerOptimal Elon®?

Visit our website at www.poweroptimal.com or contact the PowerOptimal team for more information and technical data sheets.

CONTACT US TODAY TO GET A QUOTE OR LEARN MORE ABOUT THE POWEROPTIMAL ELON®

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Patented: GB2583814, ZA2019/02129


PowerOptimal contact page: https://poweroptimal.com/contact-us/

Brochures

PowerOptimal Elon® 100 kit easy selection guide V2.13

Elon® 100 kit easy selection guide: element matching

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Elon® 100 kit easy selection guide: how much hot water?

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Typical kit contents

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Product Specifications

Product Specifications

PowerOptimal Elon® 100 specification V2.20

INTRODUCING THE

PowerOptimal Elon® 100

The innovative PowerOptimal Elon® 100 incorporates proprietary solar PV (photovoltaic) power management technology to allow for direct connection of solar PV arrays to electric geysers (water heaters) with optimised solar power use in a single compact unit. The system can be connected to the grid (AC mains) as well, and intelligently switches between AC and solar power supply. The system requires no inverter and no battery. It can be connected to standard AC geyser heating elements and AC thermostats, which translates into the most cost-effective solar water heating option today.

Document Version: 2.20

SPECIFICATIONS

Rated input voltage

250V AC, 250V DC

Rated input current

25A AC, 20A DC

Mains (AC) voltage range (over-voltage & undervoltage protection)

-50% to +100%. Overvoltage protection up to 500V and undervoltage protection down to 125V. Will disconnect all loads when breach is greater than +/- 15%.

System power supply

Solar or 230V AC mains

Power consumption

<3W on mains power; <0.5W on solar power

Shutdown

Sufficient power supply capacity to manage processor, switching and data storage if both mains and solar supply fail

Solar voltage (Voc at STC)

20 – 250 V DC

Solar power availability sensing

Automatically determines availability of sufficient solar power before supplying load from solar PV array

Controller settings

Can be adjusted to run from “solar only” (100% solar energy use) to “mains only” (no solar energy use) with 3 settings in between to allocate different proportions of the day to solar and mains.

Thermostat

Uses the standard thermostat switch associated with the geyser element as a sensor only, with less than 10mA sense current, to control power to the element

Reverse polarity protection

Protected against reverse connection of solar array

Enclosure ingress protection rating

Elon 100 main unit: IP65

Elon 100 remote control: IP40 (install indoors or in waterproof enclosure)

Max. distance Elon® unit to controller

10 m (can be extended)

Annual energy production compared to inverter-based system

> 90% when solar array and geyser element are matched correctly

Standards conformance

IEC / SANS 60669-1, 60669-2-1, 60730-1, 60335-1, 60335-2-21, CISPR 11 & IEC 61000-6-1

Dimensions & weight

Elon® 100 main unit: 200 x 150 x 90 mm (LxWxH), 1.75 kg. Controller: 50 x 72 x 41 mm (LxWxH)

Box information (for shipping): 230 x 150 x 150 mm (LxWxH), 2 kg.

Patents

ZA 2019/02129

It is important to match the solar PV array and heating elements for maximum power transfer efficiency. See Table 1B for the recommended AC heating element power rating for different solar panel specifications and configurations.

Contact PowerOptimal for advice on module-element matching if module properties are significantly different to typical values or for bifacial, high current or high voltage modules.

TABLE 1A. ELON® KIT EASY SELECTION GUIDE – HOW MANY SOLAR PV MODULES DO I NEED?

The below table provides an easy selection guide based on number of people in the household and/or hot water use (showers/day). Minimum recommended array size is 1 kWp. More detailed information and selection guidelines are provided in Tables 2-7.PowerOptimal Elon® 100 kit easy selection guide V2.13 - slide 2.png

TABLE 1B. ELON® KIT EASY SELECTION GUIDE – WHAT SIZE GEYSER ELEMENT IS THE BEST MATCH?

To get the best performance from your Elon® solar PV water heater, it is important that the geyser element is a good match for the size of your solar PV array. This table helps you match the size of the solar PV array with the size of the geyser element.

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TABLE 2. ANNUAL AVERAGE LITRES OF WATER HEATED PER DAY

The below example table indicates the average number of litres of water per day that the system will heat from 15 to 60 °C over a year period for different solar array peak power ratings. (The amount of water heated will vary with weather conditions, by geographic location and by season. Water heated per day will be significantly lower in winter and significantly higher in summer. These numbers indicate heating capacity – i.e. if no hot water is used on a given day, there will be less water heated on that day. This is only an approximate guide.)

 

Solar + Elon®

Annual average litres of water heated per day for X kWp installed solar capacity

Location

kWh/kWp/yr

0.8 kWp

1 kWp

1.2 kWp

1.4 kWp

1.6 kWp

1.8 kWp

2 kWp

2.5 kWp

3 kWp

3.5 kWp

Bloemfontein

1894

80

99

119

139

159

179

199

249

298

348

Cape Town

1624

68

85

102

119

136

154

171

213

256

299

Durban

1447

61

76

91

106

122

137

152

190

228

266

Jhb/Pretoria

1724

72

91

109

127

145

163

181

226

272

317

Mbombela

1627

68

85

103

120

137

154

171

214

256

299

Port Elizabeth

1565

66

82

99

115

132

148

164

205

247

288

Upington

1912

80

100

121

141

161

181

201

251

301

352

Saldanha

1623

68

85

102

119

136

153

170

213

256

298

Example:

For a solar PV array of 1.2 kWp, an installation in Johannesburg would yield about 1724 kWh/kWp/yr, or 1724 x 1.2 kWp = 2069 kWh/yr. This would be sufficient to heat on average 109 litres of water per day. For a family of 2 each using 80 litres of hot water per day, this would provide about 109 ÷ (80 x 2) or 68% of the annual hot water requirement.

TABLE 3. ANNUAL AVERAGE NUMBER OF SHOWERS PER DAY

The below table indicates the average number of showers per day for which the system will supply hot water over a year period for different solar array peak power ratings. (The amount of water heated will vary with weather conditions, by geographic location and by season. Water heated per day will be significantly lower in winter and significantly higher in summer. These numbers indicate heating capacity – i.e. if no hot water is used on a given day, there will be less water heated on that day. This is only an approximate guide.)

 

Solar + Elon®

Number of showers per day (based on annual average) for X kWp installed solar capacity

Location

kWh/kWp/yr

0.8 kWp

1 kWp

1.2 kWp

1.4 kWp

1.6 kWp

1.8 kWp

2 kWp

2.5 kWp

3 kWp

3.5 kWp

Bloemfontein

1894

2.4

3.0

3.6

4.2

4.8

5.4

6.0

7.5

9.0

10.4

Cape Town

1624

2.0

2.6

3.1

3.6

4.1

4.6

5.1

6.4

7.7

9.0

Durban

1447

1.8

2.3

2.7

3.2

3.6

4.1

4.6

5.7

6.8

8.0

Jhb/Pretoria

1724

2.2

2.7

3.3

3.8

4.3

4.9

5.4

6.8

8.2

9.5

Mbombela

1627

2.1

2.6

3.1

3.6

4.1

4.6

5.1

6.4

7.7

9.0

Port Elizabeth

1565

2.0

2.5

3.0

3.5

3.9

4.4

4.9

6.2

7.4

8.6

Upington

1912

2.4

3.0

3.6

4.2

4.8

5.4

6.0

7.5

9.0

10.5

Saldanha

1623

2.0

2.6

3.1

3.6

4.1

4.6

5.1

6.4

7.7

9.0

The table is based on 6-minute showers at 40 °C and 8 litres/min low flow showerheads. Old showerheads can use up to 15 litres/min and would substantially reduce the number of showers.

Example:

For a solar PV array of 2.5 kWp, an installation in Johannesburg would yield about 1724 kWh/kWp/yr, or 1724 x 2.5 kWp = 4 310 kWh/yr. This would be sufficient for about 6 to 7 showers per day.

TABLE 4. PERCENTAGE OF ANNUAL HOT WATER REQUIREMENT

The below example table indicates what % of the annual hot water requirement will on average be supplied by the system for 2 people each using 80 litres of hot (60 °C) water per day. (The amount of water heated will vary with weather conditions, by geographic location and by season. Water heated per day will be significantly lower in winter and significantly higher in summer. These numbers indicate heating capacity – i.e. if no hot water is used on a given day, there will be less water heated on that day. This is only an approximate guide.)

 

Solar + Elon®

Annual average % of hot water requirement supplied for 2 people each using 80 litres of hot water per day for X kWp installed solar capacity

Location

kWh/kWp/yr

0.8 kWp

1 kWp

1.2 kWp

1.4 kWp

1.6 kWp

1.8 kWp

2 kWp

2.5 kWp

3 kWp

3.5 kWp

Bloemfontein

1894

50%

62%

75%

87%

99%

112%

124%

155%

187%

218%

Cape Town

1624

43%

53%

64%

75%

85%

96%

107%

133%

160%

187%

Durban

1447

38%

47%

57%

66%

76%

85%

95%

119%

142%

166%

Jhb/Pretoria

1724

45%

57%

68%

79%

91%

102%

113%

142%

170%

198%

Nelspruit

1627

43%

53%

64%

75%

85%

96%

107%

134%

160%

187%

Port Elizabeth

1565

41%

51%

62%

72%

82%

92%

103%

128%

154%

180%

Upington

1912

50%

63%

75%

88%

100%

113%

126%

157%

188%

220%

Saldanha

1623

43%

53%

64%

75%

85%

96%

107%

133%

160%

186%

Examples:

An array of 1.2 kWp will provide approximately 64% of the annual hot water requirement for a family of two people in Cape Town.

An array of 2 kWp will provide approximately 124% x (2 / 4) = 62% of the annual hot water requirement for a family of four people in Bloemfontein.

TABLE 5. PEAK POWER OUTPUT FOR VARIOUS SOLAR MODULES AND ARRAY SIZES

The peak power production (Wp) of the modules at STC (Standard Test Conditions: irradiance 1000 W/m², spectrum AM 1.5, module temperature 25 °C) and at NOCT (Nominal Operating Cell Temperature, irradiance 800 W/m², spectrum AM 1.5, module temperature ~43 – 45 °C) are provided by the solar PV module manufacturer. The below table indicates the peak power at STC for a range of solar module power ratings and array sizes.

No. of cells per module

Module STC power rating (Wp)

Total peak power at STC in kWp for an array of X modules

3

modules

4 modules

5 modules

6 modules

8 (2 x 4) modules

10 (2 x 5) modules

12 (2 x 6) modules

60 or 120

265

0.795

1.06

1.325

1.59

2.12

2.65

3.18

60 or 120

270

0.81

1.08

1.35

1.62

2.16

2.70

3.24

60 or 120

275

0.825

1.10

1.375

1.65

2.20

2.75

3.30

60 or 120

280

0.84

1.12

1.40

1.68

2.24

2.80

3.36

60 or 120

285

0.855

1.14

1.425

1.71

2.28

2.85

3.42

60 or 120

290

0.87

1.16

1.45

1.74

2.32

2.90

3.48

60 or 120

295

0.885

1.18

1.475

1.77

2.36

2.95

3.54

60 or 120

300

0.90

1.20

1.50

1.80

2.40

3.00

3.60

60 or 120

305

0.915

1.22

1.525

1.83

2.44

3.05

3.66

60 or 120

310

0.93

1.24

1.55

1.86

2.48

3.1

3.72

60 or 120

315

0.945

1.26

1.575

1.89

2.52

3.15

3.78

60 or 120

320

0.96

1.28

1.6

1.92

2.56

3.2

3.84

60 or 120

325

0.975

1.3

1.625

1.95

2.6

3.25

3.9

60 or 120

330

0.99

1.32

1.65

1.98

2.64

3.3

3.96

72 or 144

310

0.93

1.24

1.55

1.86

2.48

3.10

3.72

72 or 144

315

0.945

1.26

1.575

1.89

2.52

3.15

3.78

72 or 144

320

0.96

1.28

1.60

1.92

2.56

3.20

3.84

NOT ALLOWED

(exceeds maximum rated Elon® 100 voltage)

72 or 144

325

0.975

1.30

1.625

1.95

2.60

3.25

3.90

72 or 144

330

0.99

1.32

1.65

1.98

2.64

3.30

3.96

72 or 144

335

1.005

1.34

1.675

2.01

2.68

3.35

4.02

72 or 144

340

1.02

1.36

1.70

NOT ALLOWED

(exceeds maximum rated Elon® 100 voltage)

2.04

2.72

3.40

4.08

72 or 144

345

1.035

1.38

1.725

2.07

2.76

3.45

4.14

72 or 144

350

1.05

1.40

1.75

2.10

2.80

3.50

4.20

72 or 144

355

1.065

1.42

1.775

2.13

2.84

3.55

4.26

72 or 144

360

1.08

1.44

1.8

2.16

2.88

3.6

4.32

72 or 144

365

1.095

1.46

1.825

2.19

2.92

3.65

4.38

72 or 144

370

1.11

1.48

1.85

2.22

2.96

3.7

4.44

72 or 144

375

1.125

1.5

1.875

2.25

3

3.75

4.5

72 or 144

380

1.14

1.52

1.9

2.28

3.04

3.8

4.56

72 or 144

385

1.155

1.54

1.925

2.31

3.08

3.85

4.62

72 or 144

390

1.17

1.56

1.95

2.34

3.12

3.9

4.68

72 or 144

395

1.185

1.58

1.975

2.37

3.16

3.95

4.74

72 or 144

400

1.2

1.6

2

2.4

3.2

4

4.8

72 or 144

405

1.215

1.62

2.025

2.43

3.24

4.05

4.86

72 or 144

410

1.23

1.64

2.05

2.46

3.28

4.1

4.92

72 or 144

415

1.245

1.66

2.075

2.49

NOT ALLOWED

(exceeds maximum rated Elon® 100 voltage)

3.32

4.15

4.98

72 or 144

420

1.26

1.68

2.1

2.52

3.36

4.2

5.04

NOT ALLOWED

(exceeds maximum rated Elon® 100 voltage)

72 or 144

425

1.275

1.7

2.125

2.55

3.4

4.25

5.1

72 or 144

430

1.29

1.72

2.15

2.58

3.44

4.3

NOT ALLOWED

(exceeds maximum Elon® 100 power rating)

5.16

72 or 144

435

1.305

1.74

2.175

2.61

3.48

4.35

5.22

72 or 144

440

1.32

1.76

2.2

2.64

3.52

4.4

5.28

72 or 144

445

1.335

1.78

2.225

2.67

3.56

4.45

5.34

72 or 144

450

1.35

1.8

2.25

2.7

3.6

4.5

5.4

72 or 144

455

1.365

1.82

2.275

2.73

3.64

4.55

5.46

Examples:

An array of 4 x 325 Wp modules in series will have a total peak power (at STC) of 1.3 kWp.

An array of 2 parallel strings of 5 modules of 280 Wp each (10 modules of 280 Wp in total) will have a total peak power (at STC) of 2.8 kWp.

Installation & User Manuals

Installation & User Manuals

PowerOptimal Elon® 100 Quick Reference User Guide v2.08


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PowerOptimal Elon® 100 Quick Reference User Guide v2.08 p2.png

Image result for play button orange

Online user instruction video: www.poweroptimal.com/elon100

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Full user manual: www.poweroptimal.com/manuals

V 2.08

Installation & User Manuals

PowerOptimal Elon® 100 User Manual v2.20

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PowerOptimal Elon® 100 User Manual

Version number: 2.20

Version date: 2025/12/28

Address: Postnet Suite 21, Private Bag X21, Tyger Valley, 7536

Patented: ZA2019/02129

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SAFETY WARNING

Refer to the PowerOptimal website for the following:

img-004.png Elon® 100 Installation Guide & Quick Reference User Guide

www.poweroptimal.com/manuals

img-005.png Online User Instructions Video

www.poweroptimal.com/elon100

img-006.pngOnline Elon® Basic Training Course

https://moolmaninstitute.com/p/elon-course

Table of Contents

Table of Contents

1. Introduction

1.1 System overview

1.2 Main system components

1.3 Deciding on size of Elon® system (basic guide)

2. Operation

2.1 Elon® 100 controller

2.2 Mains and solar indicator lights

2.3 Control dial settings

2.4 Holiday settings

2.5 How to maximise your savings

3. Maintenance

3.1 Solar PV module maintenance

4. What to expect in terms of performance

4.1 Hot water production

4.2 Impact of location and seasons

4.3 Payback period

5. Troubleshooting

5.1 Troubleshooting Guide for Users

5.2 Troubleshooting Guide for Electricians

Appendix A. IEC/SANS and EMC Test Certificates: Elon® 100

Appendix B. Warranty

Appendix C. Terminology

Notes

1. Introduction

Thank you for buying the PowerOptimal Elon® 100 solar PV water heating unit! You can look forward to many years of savings and free energy from the sun.

1.1 System overview

The PowerOptimal Elon® 100 operates on a very simple principle: it enables you to connect solar PV modules directly to a standard geyser with alternating current (AC) heating element and AC thermostat, with no need for an inverter. It uses the water in your geyser as a battery to store solar energy in the form of heat.

You can connect the system completely off-grid or connect it to your existing grid AC power supply. Connecting the system to the existing grid supply allows for grid power backup in case of cloudy / overcast days, or where you use more hot water than your solar PV array can generate.

Note: the system is designed in such a way that there is no possibility of solar array-produced electricity feeding back into the grid. For municipal registration purposes it is classified as "off-grid".

Below is a simplified layout of the main components of the water heating system.

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An array of solar modules (a string of 3 to 6 solar modules connected in series, or two parallel strings of 4, 5 or 6 solar modules each) is connected to the Elon® 100. Grid electricity is also connected to the Elon® 100.

The Elon® 100 is connected to the geyser element and thermostat.

When the solar modules are producing electricity, the Elon® 100 feeds this into the geyser element to heat water, until the water reaches the temperature setting on the thermostat.

The Elon® 100 controller dial setting (see Section 2.3) will determine if or when the Elon® 100 will boost the water heating with grid electricity.

1.2 Main system components

The main components of the system are as follows:

1.3 Deciding on size of Elon® system (basic guide)

The table below provides a basic guide to selecting the size of your Elon® system based on number of people in the household and/or hot water use. The Installation Manual (which you can download from www.poweroptimal.com/manuals) contains a more detailed guide.

HOW MANY SOLAR PV MODULES DO I NEED?

PowerOptimal Elon® 100 kit easy selection guide V2.13 - slide 2.png

WHAT SIZE GEYSER ELEMENT IS THE BEST MATCH?

PowerOptimal Elon® 100 kit easy selection guide V2.13 - slide 1.png

2. Operation

Refer to our easy-to-understand instruction video on how to use the Elon 100.

img-061.png Instruction video: www.poweroptimal.com/elon100

2.1 Elon® 100 controller

El0n 100 control dial guide.png

Your Elon® 100 has a controller that is typically installed next to your DB (distribution board). The controller has two main functions:

1. INDICATING ACTIVITY AND STATUS: 

Indicating heating activity and status through the mains (red) & solar (green) indicator lights (Section 2.2)

2. CONTROL TIMING: 

Setting the timing on the control dial (Section 2.3)

2.2 Mains and solar indicator lights

The Mains & solar indicator lights indicate the following conditions:

El0n 100 mains & solar indicator lights.png

2.3 Control dial settings

Elon 100 control dial settings.png

Think of the water in your geyser as a battery that can store energy in the form of hot water. To charge the battery (or heat the water) with solar energy during the day, it must cool down a bit in the morning. In other words, the water must be below its setpoint temperature by the time the sun comes up.

The Elon® achieves this by switching off mains power at some time in the morning, while you are still using hot water from the geyser. The table above indicates approximate switching times for different dial settings.

As you can see, as you turn the control dial from “MAINS ONLY” to “SOLAR ONLY”, the time period during which mains power is allowed to heat the water decreases to zero.

When the control dial is set to "MAINS ONLY", your geyser will use mains power 24 hours a day (in other words, it will never switch to solar power). The geyser will behave the same as any standard geyser.

Why would I ever want to set the control dial to “MAINS ONLY”?

Here are some example reasons why you might want to set the control dial to “MAINS ONLY”:

If you only use hot water early morning and in the evenings, you can set it just outside the “SOLAR ONLY” zone (around the “3” mark) to benefit from a longer solar energy heating period (and save more money).

When the control dial is set to “SOLAR ONLY”, the Elon® 100 will ONLY use solar power to heat water.

If you set the control dial to “SOLAR ONLY”, you can increase the geyser thermostat temperature to 60 ºC to get maximum benefit from your solar array installation. We do not recommend setting the thermostat temperature above 60 °C. Remember to reduce the thermostat temperature again if you reduce the efficiency setting.

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Warning: Do not set thermostat temperature above 65 ºC due to increased scalding risk. Be careful when opening hot water taps located close to your geyser. You can install a thermostatic mixing valve to reduce the risk of scalding – ask your plumber.

Please note: DO NOT install a separate timer on the AC side to try and regulate mains power use. Use only the Elon’s control dial to control mains power use. If you install a second timer, it will work at cross-purposes with the Elon and you will reduce performance and hot water availability.

Can I boost the water temperature with a single grid heating cycle whilst on “SOLAR ONLY” or any of the other settings?

The answer is YES. To boost water temperature to setpoint with a single grid heating cycle, turn the dial into “MAINS ONLY” until the red light starts flashing. Then turn the dial back to whatever previous setting it was on (or whatever setting you wish it to be on after the single grid heating cycle). The Elon will complete the single grid heating cycle (in other words, heat the water with grid power until it reaches the temperature set point) and then return to whatever setting you leave the control dial on.

2.4 Holiday settings

What setting should I use when I go on holiday?

You can either switch off both solar and mains power OR you can switch off mains power.

Setting

How to set it

Benefits & comments

Mains power off

Turn dial to SOLAR ONLY

You will have hot water on your return, and it will cost you nothing. It will also prevent Legionella growth in your geyser.

Both Mains & Solar power off

Turn dial to MAINS ONLY and switch off geyser at distribution board

Remember to switch system on when you return.

2.5 How to maximise your savings

Control dial

The best way to maximise your savings is to set the Elon® control dial to “SOLAR ONLY”. This will ensure that the unit will never use grid (mains) power for heating water. You can still boost with mains power (for example on a cloudy day) by turning the dial to "MAINS ONLY" if needed.

However, the "SOLAR ONLY" setting will only be feasible if you have enough solar PV modules for your household (see the table in Section 1.3 above).

For most people, setting the dial at "3" will yield the most savings whilst maintaining hot water availability mornings and evenings.

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Please note: The water in your geyser should be heated to 60 °C at least once a week to prevent Legionella bacterial growth[1]. If you have heavily overcast weather for more than a week on the SOLAR ONLY setting, turn the dial clockwise outside of the SOLAR ONLY zone for a day in order to supplement the solar water heating with grid electricity to reach the thermostat temperature setting.

When is the best time to shower?

If the control dial is set to “SOLAR ONLY”, it is best for people in the household to shower either in the morning or in the evening, but not both. (If you shower in the evening, cold water will mix with the remaining warm water overnight, and you will have cold water the next morning. If you do not shower again in the morning, the water will be heated during the day.)

If the control dial is set to any setting outside “SOLAR ONLY” or "MAINS ONLY", it is best to shower in the morning for maximum savings.

General hot water energy saving tips

South Africa is a water-scarce country – reducing hot water use saves both energy and water!

3. Maintenance

The Elon® 100 has been designed to last for a very long time and has no moving parts aside from three electrical relays. No maintenance is required on the Elon® 100.

3.1 Solar PV module maintenance

  1. At least once a week, check whether the indicator lights are flashing rapidly. (This indicates an isolation fault – call your electrician.)
  2. Perform regular visual checks (at least once a year). Check for soiling or any visible damage to any of the modules.
  3. If the modules have been soiled by dirt, dust, debris, bird droppings or any other materials, use water only and a sponge or soft cloth to clean them. Do the cleaning early in the morning or late in the afternoon, as the modules are hot during the day. Avoid using a water jet that may leave streaks on the modules.
  4. Visually inspect cables for any degradation or loose fittings.
  5. Look for any shading problems, such as trees that may have grown.
  6. An electrician can check solar power production on a sunny day to ensure that the system is still producing power at expected levels. A thermal imaging camera can be used to inspect modules for hot spots.
  7. Follow any specific maintenance instructions from the solar PV module manufacturer.

4. What to expect in terms of performance

4.1 Hot water production

Heating water takes a LOT of energy. A household geyser can use up to 40% of a house’s electricity. Heating a single 200 litre geyser from 15 °C to 60 °C will use over 10 kWh. This is about the same amount of energy burnt by a person running a distance of over 100 km at 10 km/hr, or enough energy to watch more than 120 hours of TV[2].

The more solar panels you have on your roof, the faster the Elon® 100 system will heat your water. Typically, the number of panels has been selected to heat water over most of the sunlight hours (from morning to afternoon). This will be slower than heating water using grid electricity. So you can expect a gradual temperature rise from morning to afternoon.

img-076.png

As one would expect, hot water production increases with increase in number of solar panels. Keep in mind that these numbers are averages over the year. This means that you should expect a lower number in winter and a higher number in summer.

4.2 Impact of location and seasons

The amount of energy from the sun depends on your location, the time of year as well as the orientation of your solar panels. The best direction for panels in South Africa is to face north, at an angle of about 25 to 35° from horizontal.

img-077.png

Although Gauteng (Johannesburg / Pretoria) & Cape Town may seem quite similar in terms of total solar energy per year, Cape Town has winter rainfall and Gauteng has summer rainfall. This leads to Cape Town having much lower solar electricity production than Gauteng in winter (see the below graph).

img-078.png

4.3 Payback period

img-079.png

As can be seen from the graph above, payback period decreases as number of solar panels increases, and is also different for Johannesburg, Cape Town and Durban[3].

The reason that payback period improves (decreases) as number of solar panels increases, is because there are some fixed costs (such as engineering design & safety components) and some costs that do not scale linearly with array size (such as labour, wiring, mounting kit costs, etc.).

5. Troubleshooting

5.1 Troubleshooting Guide for Users

img-080.png

Below you can find the same information with some further detail in table format. If you cannot resolve the problem using the diagram or table, please contact your installer.

Issue

Possible causes

What to do

Water temperature too low
  1. High hot water usage levels
  2. Cloudy or rainy day
  3. Dirty solar modules
  4. Mains circuit breaker has tripped
  5. Thermostat connection or thermostat defective
  1. Turn control dial clockwise (2.3) OR Reduce hot water use (2.5) OR Add additional solar modules to your solar installation (first consult with your installer)
  2. See 1 above
  3. Inspect solar modules. If they are soiled, clean them with water and sponge (4.1)
  4. Check mains circuit breaker
  5. Call electrician for inspection

Water temperature remains low after turning dial to "MAINS ONLY". (Note: the red LED light should start flashing once dial is turned to “MAINS ONLY”, indicating that the water is being heated.)
  1. Sufficient time has not been provided for water to be heated after dial has been turned
  2. It is a cloudy day and there is a mains power failure
  3. There is an electrical fault or the Elon® 100 is defective
  4. Thermostat connection or thermostat or element defective
  1. Wait for 2 hours after turning the dial to “MAINS ONLY”.
  2. You will have to wait until either the solar or grid power returns to heat the water
  3. Check if the mains light on the Elon® 100 controller starts flashing after you turn the dial to "MAINS ONLY". If it does not and your water remains cold, call your electrician to inspect the installation for any electrical fault.
  4. Call electrician for inspection

Water temperature too high
  1. Thermostat temperature setting is high and you are using hot water from a tap close to the geyser
  2. Thermostat connection or thermostat defective
  1. Reduce thermostat temperature set point OR Open the cold water tap first OR Install a thermostatic mixing valve
  2. Call electrician for inspection.

Hot water production is lower than it used to be
  1. Dirty solar modules
  2. Trees / plants have grown and are causing shaded areas on solar modules
  3. Damage to solar modules
  1. Inspect solar modules. If they are soiled, clean them with water and sponge (4.1)
  2. Trim trees and plants
  3. Installer or electrician should test solar array power production in sunny conditions and compare with specifications. If one or more modules are damaged and they are still under warranty, contact manufacturer for replacement

Both indicator lights off
  1. There is a power failure and it is overcast or night-time
  2. Geyser breaker at DB board switched off and it is overcast or night-time
  3. Mains power is over- or under-voltage
  1. Wait until power or sun returns and check if any indicator light comes on.
  2. Switch on breaker at DB board.
  3. If actions in a. and b. above do not resolve the issue, call your electrician.

Red or green indicator light flashing very fast
  1. Isolation fault
  1. Please call your electrician.

5.2 Troubleshooting Guide for Electricians

NOTE: This Troubleshooting Guide is intended for electricians and not general users. Users should please refer to Section 5.1.

Things to Remember

Troubleshooting Steps

  1. 🞏 Confirm correct wiring and polarity to Elon®. Also confirm test meter wires are connected correctly, black to common!
  2. 🞏 Confirm correct voltages and currents of all connections through the following steps:
    • Confirm open / closed thermostat voltages (11 – 14 V DC open, 0 V DC closed).
    • Confirm controller wire is connected properly. The connections should “click” into place and appropriate LEDs should indicate (be active).
    • With solar power to element switched on (green LED flashing), confirm same DC voltage to element as measured at solar terminals.
    • With DC clamp meter confirm that there is an active current through element.
    • With mains power to element switched on (red LED flashing), confirm same AC voltage to element as measured at mains terminals (should be approx. 230V AC).
    • With AC clamp meter confirm active current through element of between 9 and 18 Amps depending on element rating.
  3. 🞏 If you used a test controller for troubleshooting, remember to plug the wire from the installed controller back into the Elon® and check functioning. Set thermostat back to original setting.

 

Appendix A. IEC/SANS and EMC Test Certificates: Elon® 100

img-081.png

img-082.png

img-083.png

img-084.png

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Appendix B. Warranty

If the PowerOptimal Elon® 100 (“the Product”) is found to be defective, you will be entitled to a repair or replacement within 2 (two) years of the date of delivery of the Product to you. Please keep your receipt as proof of purchase. If you are a consumer as defined in the Consumer Protection Act No. 68 of 2008 (“the CPA”), you will be entitled to such remedies as are made available under the CPA in relation to the return of goods.

PowerOptimal will not have any liability or obligation to you where the Product has been subjected to abuse, misuse, improper use, improper testing, negligence, accident, alteration, tampering or repair by a third party.

To the maximum extent permitted by applicable law, in no event shall PowerOptimal be liable for any special, incidental, indirect, or consequential damages whatsoever, including, without limitation, damages for loss of business profits or business interruption, arising out of the use or inability to use this product.

Please note that this unit must be installed by an electrical contractor registered with the Department of Labour. Failure to do so may invalidate this warranty. Please keep the CoC (Certificate of Compliance) issued by the electrical contractor on completion of the installation.

Appendix C. Terminology

AC Alternating Current – an electric current that reverses its direction many times a second at regular intervals, with voltage typically varying in the form of a sine wave.

CoC Certificate of Compliance – to be issued by the electrician installing your Elon® 100 system

CPA Consumer Protection Act No. 68 of 2008

DB Distribution board – the main electrical distribution board / panel in your home, containing circuit breakers and switches.

DC Direct Current – an electric current flowing in one direction only. Solar PV modules produce direct current electricity.

Geyser South African term for a water heater

IEC International Electrotechnical Commission

kWh A derived unit of energy equal to 3.6 MJ (megajoules). The amount of energy used by a 1 kW electrical device over a period of 1 hour.

kWp or Wp The peak power rating in kilowatt (kW) or watt (W) of a solar module or array – i.e. the output power achieved under full solar radiation. This is usually reported at STC and NOCT.

PV Photovoltaic – referring to the production of electric current at the junction of two materials exposed to light.

SANS South African National Standards

Notes

  1. See for example: http://www.eskom.co.za/sites/idm/Documents/‌Legionaires_Fact_sheet‌_hot_water‌_bacteria‌_simple_facts.pdf and http://standards.nsf.org/apps/group_public/download.php/‌30413/How%20to%20Avoid%20LD%20at%20Home.pdf ↑

  2. 46” OLED TV at 82W. ↑

  3. Calculations based on actual Elon performance, assuming a 20% reduction due to non-optimal user behaviour, an initial electricity tariff of R3/kWh and an annual electricity price increase of 8%. ↑

Installation & User Manuals

PowerOptimal Elon® 100 Installation Manual v2.30

img-002.png

Version date: 2025/12/28

Enquiries: info@poweroptimal.com

Address: Postnet Suite 21, Private Bag X21, Tyger Valley, 7536

Patented: ZA2019/02129

img-003.png

SAFETY WARNING

Refer to the PowerOptimal website for the following:

img-004.png Elon® 100 User Manual

 

www.poweroptimal.com/manuals

img-005.png Training videos for electricians

 

www.poweroptimal.com/elon-100-training

img-006.png Online User Instructions Video

 

www.poweroptimal.com/elon100

img-007.png Online Elon® Basic Training Course

 

https://moolmaninstitute.com/p/elon-course

Table of Contents

Table of Contents

1. Required tools

2. Basic wiring diagram

3. Solar PV array installation

4. Elon® 100 installation

5. Element installation (retrofit)

Appendix A. Basic Troubleshooting Guide for Electricians 

Appendix B. Solar yield 

B1. Solar irradiance levels 

B2. Geographic features 

B3. Azimuth / horizontal angle 

B4. Inclination or tilt angle 

B5. Shading 

B6. Ambient temperature 

B7. Minimum distance from roof edges

Appendix C. Deciding on Size of Solar Array

Appendix D. PV array and geyser (water heater) element matching

Appendix E. Technical Specification Summary: Elon® 100

Appendix F. Surge Protection Device (SPD) Recommendations

F1. SANS 10142-1 The wiring of premises Part 1: Low-voltage installations

F2. Draft standard SANS 10142-3 Proposed Interim Guideline for the wiring of LV grid-embedded PV installations not exceeding 1000kVA in South Africa

Appendix G. IEC/SANS and EMC Test Certificates: Elon® 100 

Appendix H. Warranty

Appendix I. Terminology 

Notes

1. Required tools

The following tools are required for the installation. Use insulated tools wherever applicable.

2. Basic wiring diagram

img-008.png

Note 1: Both AC & DC circuit breakers or isolators must be installed within 1.5m of the geyser (water heater), line of sight.

Note 2: Surge Protection Device (SPD) only required in higher lightning strike density areas (such as parts of Gauteng and Mpumalanga), or where the DC cables are long. See Appendix F.

img-010.png

Wiring detail: Elon 100 with wiring kit

Wiring kit for Elon 100:

img-016.png

Wiring diagram for Elon 100 with wiring kit:

img-009.png

Note: Surge Protection Device (SPD) only required in higher lightning strike density areas (such as parts of Gauteng and Mpumalanga), or where the DC cables are long. See Appendix F.

Wiring detail: Elon 100 with element adapter

Element adapter side view and front view:

img-014.pngimg-015.png

Wiring diagram: Elon 100 with element adapter:

img-011.png

Note: Surge Protection Device (SPD) only required in higher lightning strike density areas (such as parts of Gauteng and Mpumalanga), or where the DC cables are long. See Appendix F.

3. Solar PV array installation

Modules should ONLY be installed by a trained solar PV installation technician. Array position and orientation have a major impact on power production (see Appendix B).

Review the instructions from your solar PV module supplier / manufacturer on installation.

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Please note: Your installer should comply with SANS 10142-1 (Standard for low voltage installations) and SANS 60364-7-712 when doing your solar PV installation. If they are not well familiar with these standards, you should look for a different solar PV installer.

SAPVIA (South African Photovoltaic Industry Association) has made available an excellent guide to solar PV installations. See:

https://www.pvgreencard.co.za/Solar%20PV%20Guidelines%20-%20Digital%20‌Spread%20High-res.pdf

NB: Refer to Appendices C & D for guidelines on selecting the right size solar PV array for the user requirements, and for correctly matching the solar PV array and the geyser element.

The below installation steps are a general guide only – compliance with the abovementioned standards is compulsory.

  1. A critical starting point is safety gear: ensure that all installers wear a helmet and insulated safety gloves, as well as fall protection safety gear if work will be done on a roof or elevated area.
  2. The solar PV array should only consist of one string of 2 to 6 modules in series, or two parallel strings 2 to 5 modules each. Do not exceed the DC voltage or current ratings of the Elon® 100 (240V DC and 20A DC) under any circumstances. Do not exceed the maximum power rating of 4 kWp.
  3. Attach bracket / mounting structure to roof. Use mounting structure recommended by solar module supplier for roof type and size of solar modules.
  4. Fix the solar PV modules to the mounting structure whilst connecting the module cables to each other.
  5. If practical, cover the modules to ensure that there is no potential for electric shock whilst installing the system.
  6. Ground the mounting structure only.
  7. Install the wiring from the solar PV array to the Elon® 100 unit in the ceiling space. Ensure circuit breakers / isolators are in the “Open” position. Installation of a Surge Protective Device (SPD) between the solar PV array and the Elon® 100 is required in high lightning strike areas, such as parts of Gauteng and Mpumalanga. See Appendix F for more information.
  8. Last step is to connect the array to the rest of the wiring, making sure that both the positive and negative wires are fully isolated from ground and keeping circuit breakers / isolators in the “Open” position.

Some “DO’s & DON’T’s” when installing solar PV arrays:

Your solar PV installer should not make any of these basic mistakes, but they are listed here just in case.

  1. DO earth the PV array structure.
  2. DO isolate the wires from the PV array structure.
  3. DON’T use different sizes, types or specifications of modules together in the same string or array.
  4. DON’T install solar arrays where they will be partially shaded during any season of the year if it can be avoided at all.
  5. DO install the arrays so that there is space for inspection or maintenance when needed.
  6. DO use cabling of the correct size for your solar array.
  7. DON’T install the solar array flush with your rooftop. Use struts / brackets that ensure an unrestricted air gap of at least 40 mm between the roof and the modules.
  8. DON’T walk on the modules.
  9. DO ensure that connectors are kept clean and away from water.
  10. DON’T leave exposed modules in short circuit.
  11. DO ensure that all connectors are securely fastened.
  12. DON’T exceed the voltage ratings of any components.
  13. DO properly route and secure all cables.
  14. DON’T coil cables.

4. Elon® 100 installation

A note on poor geyser installations

Poor geyser installations can cause excessive heat loss, which increases electricity cost with no benefit. Check for the following:

  1. Isolate the geyser – switch off the geyser circuit breaker at the main electrical distribution board (DB) AND switch off the geyser isolator at the geyser.
  2. Confirm with a multimeter that there is no voltage across the wires.
  3. Install circuit breaker (or isolator and fuse) for solar PV (DC) supply. Also install AC supply isolator / circuit breaker if there is none. NB Ensure that the DC circuit breaker is rated for the DC voltage and current of the installed solar PV array.
  4. The circuit breakers / isolators must be installed within 1.5m of the geyser AND must be line of sight / visible (i.e. do not install them at the back of the geyser).
  5. The DC wires must not be earthed – i.e. they must be fully isolated from earth. Do NOT test with a Megger.
  6. Keep the DC wires as short as possible.
  7. Avoid any coils in DC wires.
  8. Recommended wiring size is at least 2.5 mm². Use panel wire for all connections to the Elon® 100.
  9. Install the Elon® 100 unit according to wiring diagram (see Section 2).
    1. Mount the Elon® 100 unit close to the geyser and protect from outside elements. The maximum wire length between Elon® 100 and geyser is 3 m.
    2. It is recommended to install the Elon® 100 oriented with wiring exiting downward to minimise the risk of water ingress. The enclosure is IP65, but the glands and wires represent a potential water ingress point if not installed correctly.
    3. Mount the controller (the small black remote control) inside or next to the main DB in the house or in another convenient and accessible location (for example the garage). Double-sided mounting tape and Genkem contact adhesive work well for most surfaces. When inserting the controller wire into the Elon® 100 unit, make sure the connector clicks into place.

Note: if installing the controller outside or in a humid or corrosive area (such as by the coast), install the controller in a weatherproof box, such as a weather proof plug box. Apply silicon at the bottom (cable entry point).

10. Connect the Elon® 100 and thermostat last.

You will have been provided with either a wiring kit (FOLLOW INSTRUCTIONS 10A) OR an element adapter (FOLLOW INSTRUCTIONS 10B). See also the training videos on how to install either of these here: https://www.poweroptimal.com/elon-100-training/.

10A WIRING KIT INSTRUCTIONS (follow these if you have the wiring kit as per Section 2)

Note: As per the wiring diagram, the thermostat and element should be connected to the Elon® SEPARATELY (independently).

img-017.pngimg-018.png

10A-1 For TSE and Thermowatt (RTS) thermostats, connect the connectors marked “thermostat” on the Elon® directly to the two screw terminals on the thermostat and short the two male terminals at the bottom of the thermostat together, using the bridging wire with female connectors supplied with the Elon® 100 (see the photos above). (Less than 20 mA DC current will flow through this wire – it is a sensing current only.) There must be no connection between the thermostat and the element.

img-019.pngimg-020.png

10A-2 Connect the two element terminals directly to the connectors marked “element” on the Elon®. For flange-type elements, use the supplied wiring with element connector (photos above). Make sure that the element connector fits tightly into the element and that the two male spade terminals of the connector are slotted correctly into the female terminals of the element. Crimp both terminals (you can do this through the plastic cover) to ensure a tight fit on both sides.

10A-3 Slide the thermostat (with bridging wire installed) into the thermostat pocket in the element as deep as it can go. (Slide it in rotated 180 ° from its normal orientation.)

10A-4 Continue with instructions from STEP 11.

10B ELEMENT ADAPTER INSTRUCTIONS (follow these if you have the element adapter as per Section 2)

img-022.pngimg-021.png

10B-1 Plug the thermostat into the element adapter as per photo above, ensuring a snug fit. Check that spade terminals enter female terminals correctly.

10B-2 Plug the thermostat + element adapter into the element as per Figure 4.8, ensuring a snug fit. Tug on each side to confirm correct fit.

10B-3 Wire the thermostat screw terminals directly to the connectors marked “Thermostat” on the Elon.

10B-4 Wire the element adapter directly to the connectors marked “Element” on the Elon.

10B-5 Continue with instructions from STEP 10.

11. Set the thermostat to the desired temperature (60 °C maximum). Note that vertically installed geysers have higher temperatures at the top than the bottom (this is called thermal stratification). The temperature difference is about 3 °C per meter. Reduce the setpoint temperature in vertically installed geysers to about 5 °C lower than for a horizontally installed geyser.

12. Attach labels included with the Elon 100 (see Figure 4.9 on next page):

    1. Attach "Dual Supply" labels to the AC isolator and the DC circuit breaker (or isolator).
    2. Attach "Warning – Photovoltaic Power Source" label to the DC wiring conduit in a clearly visible position.
    3. Attach "Installation Diagram" label close by the geyser in a clearly visible position – for example on a rafter. (Do not attach it directly to the geyser, as it will disappear if the geyser is replaced.)

13. Once installation is complete, do the following:

    1. Turn the control dial to "SOLAR ONLY".
    2. Switch on the AC & DC circuit breakers or isolators.
    3. Remove the covering from the solar modules.
    4. Switch on the geyser circuit breaker at the main DB.

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Label positions (see step 12)

14. Check that the Elon® 100 unit is operational (refer to LED lights on controller – see next page).

    1. Confirm solar PV array supply voltage and DC power to geyser when thermostat is closed. The Elon® 100 will switch DC power to the geyser approximately 10 to 15 seconds after DC power to the Elon® has been switched on (if there is enough sunlight). (If thermostat is not closed, open hot water tap in house until thermostat closes.)
    2. Test mains power supply by turning the dial to "MAINS ONLY". The red light should start flashing (except if geyser is already at thermostat setpoint temperature). NOTE THAT THE ELON® WILL ONLY SWITCH TO MAINS 5 MINUTES AFTER MAINS POWER SWITCH-ON OR RECONNECTION. This is to allow grid power to stabilize after a power failure.
    3. Confirm that no power is supplied to geyser element when thermostat is open (turn thermostat set point to lowest setting).
    4. Set thermostat back at desired temperature (60 °C maximum).

15. Set control dial to setting “2” (the 6 o' clock position). (For new property development installations, you can set the control dial to setting “1” (the 9 o’clock position). This ensures that new residents can settle in before deciding on the setting that suits their habits best.)

Note: if doing any maintenance, rewiring or disconnecting the Elon® 100 or geyser element for any reason, it is good practice to first switch off both the AC & DC circuit breakers / isolators, and then disconnect one of the wires between the Elon® 100 and thermostat before disconnecting the rest of the wires.

Please note: DO NOT install a separate timer on the AC side to try and regulate mains power use. Use only the Elon’s control dial to control mains power use. If you install a second timer, it will work at cross-purposes with the Elon and you will reduce performance and hot water availability.

Final step: hand over the laminated Quick Reference User Guide (included in the box) to the household (or leave it in a prominent place for them to find such as the kitchen counter).

The Mains & Solar indicator lights indicate the following conditions:

El0n 100 mains & solar indicator lights.png

The control dial sets the mains & solar times as follows:

Elon 100 control dial settings.png

5. Element installation (retrofit)

If you need to exchange the element on an existing geyser, please follow the instructions provided by the element supplier.

There are two main types of geyser heating elements: screw-in and flange type. There are three main types of thermostats: VKF-11, TSE and Thermowatt (the TSE and Thermowatt thermostats are quite similar). The below table provides a guide to Elon® compatibility with the different elements and thermostats.

Element type

Compatible thermostat type

Comments

Screw-in element:

 

img-036.jpg

VKF-11 thermostat:img-037.jpgimg-038.jpg

Element & thermostat have separate electrical connections, so each can be connected (wired) separately to the Elon®. Thus, this element-thermostat combination is directly compatible with the Elon®. (No need to use the bridging wire or element adapter supplied with the Elon® unit.)

The thermostat pocket in the element is the right size for the VKF-11 thermostat.

Do not connect the thermostat in line with the element. Connect the two thermostat wires to the two terminals marked “thermostat” on the Elon 100 unit. Connect the element separately to the two terminals marked “element” on the Elon 100 unit.

Spiral element (flange type) with smaller diameter thermostat pocket:

img-039.pngimg-040.pngimg-041.png

TSE thermostat: Thermowatt (RTS) thermostat:

img-042.png

The spiral element generally has a smaller thermostat pocket than the screw-in element. The TSE and Thermowatt (RTS) thermostats fit into this smaller pocket. The VKF-11 thermostat requires a larger pocket and does not fit into standard spiral element pockets.

The TSE and Thermowatt thermostats normally clip directly into the element, but this won’t be the case when the Elon® is connected.

Use the wiring kit or element adapter supplied with the Elon® (see Figures 4.1 and 4.2 above) to connect the Elon® to these thermostats and elements.

 

Appendix A. Basic Troubleshooting Guide for Electricians

NOTE: This Troubleshooting Guide is intended for electricians and not general users. Users should please refer to the User Manual, which can be found at www.poweroptimal.com/manuals.

Things to Remember

Troubleshooting Steps

  1. 🞏 Confirm correct wiring and polarity to Elon®. Also confirm test meter wires are connected correctly, black to common!
  2. 🞏 Confirm correct voltages and currents of all connections through the following steps:
    • Confirm open / closed thermostat voltages (11 – 14 V DC open, 0 V DC closed).
    • Confirm controller wire is connected properly. The connections should “click” into place and appropriate LEDs should indicate (be active).
    • With solar power to element switched on (green LED flashing), confirm same DC voltage to element as measured at solar terminals.
    • With DC clamp meter confirm that there is an active current through element.
    • With mains power to element switched on (red LED flashing), confirm same AC voltage to element as measured at mains terminals (should be approx. 230V AC).
    • With AC clamp meter confirm active current through element of between 9 and 18 Amps depending on element rating.
  3. 🞏 If you used a test controller for troubleshooting, remember to plug the wire from the installed controller back into the Elon® and check functioning. Set thermostat back to original setting.

 

Appendix B. Solar yield

Note: only basic information is provided here. Your solar PV installation design engineer or technician should advise on the best configuration for your specific location, roof structure, etc.

The yield produced by solar PV modules depends on several factors:

B1. Solar irradiance levels

img-043.pngThe map below shows the general solar irradiance levels (GHI or Global Horizontal Irradiance) in South Africa[1]:

You can expect the following approximate energy generation from solar modules for various locations[2]:

Location

Electricity generated kWh/kWp per year

Bloemfontein

2055

Cape Town

1762

Durban

1570

Johannesburg / Pretoria

1871

Mbombela

1766

Gqeberha / Port Elizabeth

1698

Upington

2075

B2. Geographic features

Major geographical features (such as hills or mountains) can reduce the total solar yield.

B3. Azimuth / horizontal angle

img-044.png

The azimuth refers to the horizontal orientation of the modules – in the Southern Hemisphere, by how many degrees they are oriented away from north

Due north is best in the Southern hemisphere. Modules should preferably not be oriented more than 15º away from due north.

B4. Inclination or tilt angle

The tilt angle refers to the vertical orientation of the modules – a rough guide is that the modules should be tilted at the site’s latitude. For example, Musina is 22º S, Pretoria & Johannesburg are 26º S, Bloemfontein is 29º S, Durban is 30º S and Cape Town & Port Elizabeth are 34º S.

To optimise winter performance, one can add 15º to the tilt angle. (Note: as long as you are within about 15º of the optimal latitude, the loss in efficiency is not substantial.)

B5. Shading

Solar modules lose a lot of efficiency if even a small part of the module is shaded. For example, just 3% shading can cause a 25% loss in power! Shaded cells on a module also causes hotspots, which will reduce module lifetime.

It is thus important to place the solar modules on a rooftop area that is free from shading for as much as possible of the day (and throughout the year).

B6. Ambient temperature

Solar PV modules’ performance decreases with increasing temperature. Wind will reduce the temperature of the solar array and will thus improve performance. Thus, it is important to install rooftop solar modules with an air gap of at least 40 mm between the modules and roof[3].

B7. Minimum distance from roof edges

Your solar PV design engineer should prescribe minimum clearance from roof edges that should be maintained for your area based on climatic and wind conditions. Typically, a minimum clearance of 20 to 30 cm should be maintained.

 

Appendix C. Deciding on Size of Solar Array

Terminology used

img-045.jpg

Solar power is generated by solar cells, which are arranged in framed modules, typically of 60 or 72 cells each. The total set of solar PV modules installed is referred to as a solar PV array[4].

The table below provides a basic guide to selecting the size of the solar PV array based on number of people in the household and/or hot water use. Minimum recommended size is 1 kWp. Read on for a more detailed guide.

PowerOptimal Elon® 100 kit easy selection guide V2.13 - slide 2.png

TABLE C1. ANNUAL AVERAGE LITRES OF WATER HEATED PER DAY

The below example table indicates the average number of litres of water per day that the system will heat from 15 to 60 °C over a year period for different solar array peak power ratings. (The amount of water heated will vary with weather conditions, by geographic location and by season. Water heated per day will be significantly lower in winter and significantly higher in summer. These numbers indicate heating capacity – i.e. if no hot water is used on a given day, there will be less water heated on that day. This is only an approximate guide.)

Installation manual Table C1.png

Example:

For a solar array of 1.2 kWp, an installation in Johannesburg would yield about 1724 kWh/kWp/yr, or 1724 x 1.2 kWp = 2069 kWh/yr. This would be sufficient to heat on average 109 litres of water per day. For a family of 2 each using 80 litres of hot water per day, this would provide about 109 ÷ (80 x 2) or 68% of the annual hot water requirement.

TABLE C2. ANNUAL AVERAGE NUMBER OF SHOWERS PER DAY

The below table indicates the average number of showers per day for which the system will supply hot water over a year period for different solar array peak power ratings. (The amount of water heated will vary with weather conditions, by geographic location and by season. Water heated per day will be significantly lower in winter and significantly higher in summer. These numbers indicate heating capacity – i.e. if no hot water is used on a given day, there will be less water heated on that day. This is only an approximate guide.)

Installation manual Table C2.png

The table is based on 6-minute showers at 40 °C and 8 litres/min low flow showerheads. Old showerheads can use up to 15 litres/min and would substantially reduce the number of showers.

Example:

For a solar PV array of 2.5 kWp, an installation in Johannesburg would yield about 1724 kWh/kWp/yr, or 1724 x 2.5 kWp = 4 310 kWh/yr. This would be sufficient for about 6 to 7 showers per day.

TABLE C3. PERCENTAGE OF ANNUAL HOT WATER REQUIREMENT

The below example table indicates what % of the annual hot water requirement will on average be supplied by the system for 2 people each using 80 litres of hot (60 °C) water per day. (The amount of water heated will vary with weather conditions, by geographic location and by season. Water heated per day will be significantly lower in winter and significantly higher in summer. These numbers indicate heating capacity – i.e. if no hot water is used on a given day, there will be less water heated on that day. This is only an approximate guide.)

Installation manual Table C3.png

Examples:

An array of 1.2 kWp will provide approximately 64% of the annual hot water requirement for a family of two people in Cape Town.

An array of 2 kWp will provide approximately 124% x (2 people / 4 people) = 62% of the annual hot water requirement for a family of four people in Bloemfontein.

Appendix D. PV array and geyser (water heater) element matching

It is important to match PV array specifications and heating elements for maximum power transfer efficiency. See the below table for the recommended heating element power rating for different solar array sizes.

Contact PowerOptimal for advice on module-element matching if module properties are significantly different to typical values or for advice on bifacial, high current & high voltage modules.

TABLE D1. GUIDE: PV ARRAY AND GEYSER (WATER HEATER) ELEMENT MATCHING

PowerOptimal Elon® 100 kit easy selection guide V2.13 - slide 1.png

DO NOT DEVIATE FROM THE RECOMMENDED MODULE-ELEMENT MATCHING CONFIGURATIONS WITHOUT CONSULTING POWEROPTIMAL.

Maximum allowed solar PV array specifications at Standard Test Conditions (STC):

Isc < 20A Voc < 250V Power < 4 kWp

Appendix E. Technical Specification Summary: Elon® 100

Refer to the PowerOptimal website for the full Technical Specification www.poweroptimal.com/specifications

Rated input voltage

250V AC, 250V DC

Rated input current

25A AC, 20A DC

Mains (AC) voltage range

-50% to +100% (but will disconnect all loads when breach is greater than +/- 15%)

System power supply

Solar or 230V AC mains

Power consumption

<3W on mains power; <0.5W on solar power

Shutdown

Sufficient power supply capacity to manage processor, switching and data storage if both mains and solar supply fail

Solar voltage (Voc at STC)

20 – 250 V DC

Solar energy availability

Automatically determines availability of sufficient solar energy before supplying load from solar modules

Controller settings

Can be adjusted to run from “solar only” (100% solar energy use) to "mains only" (no solar energy use)

Thermostat

Uses the standard normally open thermostat switch associated with the geyser element as a sensor only, with less than 10mA sense current, to control power to the element

Reverse polarity protection

Protected against reverse connection of solar array

Enclosure ingress protection rating

Elon 100 main unit: IP65

Elon 100 remote control: IP40 (install indoors or in waterproof enclosure)

Maximum distance Elon® unit to controller

10 m

Annual energy production compared to inverter-based system

> 90% when solar array and geyser element are matched correctly

Standards conformance

IEC / SANS 60669-1, 60669-2-1, 60730-1, 60335-1, 60335-2-21, CISPR 11 & IEC 61000-6-1

Dimensions & weight

Elon® 100 main unit: 200 x 150 x 60 mm (LxWxH), 1.75 kg. Controller: 50 x 72 x 41 mm (LxWxH)

Patents

ZA 2019/02129

It is important to match modules and heating elements for maximum power transfer efficiency. See the tables in Appendix D for the recommended heating element power rating for different solar module specifications and array configurations.

Appendix F. Surge Protection Device (SPD) Recommendations

This Appendix outlines under which circumstances a Surge Protection Device should be installed as part of a solar PV system installation such as the Elon® 100.

F1. SANS 10142-1 The wiring of premises Part 1: Low-voltage installations

Please note: compliance with SANS 10142-1 is compulsory for all electrical installations as per the Occupational Health & Safety Act.

SANS 10142-1 states the following with regards to surge protection:

6.7.6 Surge protection

6.7.6.1 Surge protective devices (SPDs) may be installed to protect an installation against transient overvoltages and surge currents such as those due to switching operations or those induced by atmospheric discharges (lightning). NOTE A risk assessment may be performed in accordance with annex Q. The Installation of SPDs is necessary where structures are equipped with external lightning protection systems (LPS) as in accordance with SANS 10313.

As can be seen above, surge protection is optional and based on a risk assessment as per Annex Q.

The risk assessment is as per the following table from SANS 10142-1 (2020):

img-099.png

Note that the “Service Line” referred to above is the incoming (AC) line for the house.

Here is a lightning density map for South Africa as provided in SANS 10142-1:

img-100.png

F2. Draft standard SANS 10142-3 Proposed Interim Guideline for the wiring of LV grid-embedded PV installations not exceeding 1000kVA in South Africa

Please note: this is only a draft standard and compliance with this standard is not compulsory. It is only provided for information purposes.

The draft standard SANS 10142-3 requires a Surge Protection Device to be installed where the length (L) of the DC cables (from PV array to Elon® 100 or inverter) exceeds the critical length Lcrit as follows:

A Surge Protection Device is required where L ≥ Lcrit

The critical length Lcrit depends on the type of PV installation and is calculated according to the following table:

Type of installation

Individual residential premises

Terrestrial production plant

Service / Industrial / Agricultural Buildings

Lcrit (in meter)

115/Ng

200/Ng

450/Ng

where Ng = lightning strike density (number of strikes/km²/yr)

The length of DC cables L is the sum of:

For the Elon® 100, distance L is the length of DC cables from PV array to the Elon® 100.

Here is a national lightning ground stroke density map for South Africa[5].

img-101.png

From Evert & Gijben (2017).

From this map, the lightning strike density (Ng) range for major cities are as follows:

Installation manual lightning strike density per city.png

 

Appendix G. IEC/SANS and EMC Test Certificates: Elon® 100

img-102.png

img-103.png

img-104.png

img-105.png

img-106.png

Appendix H. Warranty

If the PowerOptimal Elon® 100 (“the Product”) is found to be defective, you will be entitled to a repair or replacement within 2 (two) year of the date of delivery of the Product to you. Please keep your receipt as proof of purchase. If you are a consumer as defined in the Consumer Protection Act No. 68 of 2008 (“the CPA”), you will be entitled to such remedies as are made available under the CPA in relation to the return of goods.

PowerOptimal will not have any liability or obligation to you where the Product has been subjected to abuse, misuse, improper use, improper testing, negligence, accident, alteration, tampering or repair by a third party.

To the maximum extent permitted by applicable law, in no event shall PowerOptimal be liable for any special, incidental, indirect, or consequential damages whatsoever, including, without limitation, damages for loss of business profits or business interruption, arising out of the use or inability to use this product.

Please note that this unit must be installed by an electrical contractor registered with the Department of Labour. Failure to do so may invalidate this warranty. Please keep the CoC (Certificate of Compliance) issued by the electrical contractor on completion of the installation.

Appendix I. Terminology

AC Alternating Current – an electric current that reverses its direction many times a second at regular intervals, with voltage typically varying in the form of a sine wave.

CoC Certificate of Compliance – to be issued by the electrician installing your Elon® 100 system

CPA Consumer Protection Act No. 68 of 2008

DB Distribution board – the main electrical distribution board / panel in your home, containing circuit breakers and switches.

DC Direct Current – an electric current flowing in one direction only. Solar PV modules produce direct current electricity.

Geyser South African term for a water heater

IEC International Electrotechnical Commission

Impp The solar module current at maximum power point (MPP). Manufacturers usually report two Impp values: one at STC and one at NOCT.

kWh A derived unit of energy equal to 3.6 MJ (megajoules). The amount of energy used by a 1 kW electrical device over a period of 1 hour.

kWp or Wp The peak power rating in kilowatt (kW) or watt (W) of a solar module or array – i.e. the output power achieved under full solar radiation. This is usually reported at STC and NOCT.

MPP Maximum power point. This is the point on a solar cell, module or array’s power or I-V (current-voltage) curve that has the highest power output.

NOCT Nominal Operating Cell Temperature (also sometimes referred to as NMOT or Nominal Module Operating Temperature). This refers to the temperature that open circuited solar PV modules will reach under conditions that more closely match actual field operational conditions than STC. The modules are tested at 800 W/m² simulated solar irradiance, 20 °C ambient temperature, 1 m/s wind velocity and open back side mounting. Depending on the quality of the cell / module design, the NOCT can reach anything from 33 to 58 °C[6]. Since solar PV cell power output reduces with increase in temperature, a lower NOCT is better.

PV Photovoltaic – referring to the production of electric current at the junction of two materials exposed to light.

SANS South African National Standards

STC Standard Test Conditions for solar cells – 1000 W/m² simulated solar irradiance and 25 °C solar cell temperature, and an air mass 1.5 spectrum (AM1.5).

Vmpp The solar module voltage at maximum power point (MPP). Manufacturers usually report two Vmpp values: one at STC and one at NOCT.

Notes

  1. CRSES (Centre for Renewable and Sustainable Energy Studies). Website: http://www.crses.sun.ac.za/files/research/publications/SolarGIS_GHI_South_Africa_width15cm_300dpi.png. Last accessed: 07/04/2017. ↑

  2. Urban Energy Support. Website: http://www.cityenergy.org.za/uploads/resource_274.pdf. Last accessed: 07/04/2017. ↑

  3. D’Orazio M et al. 2013. Performance assessment of different roof integrated photovoltaic modules under Mediterranean Climate. ↑

  4. Image source: http://ohioline.osu.edu/factsheet/AEX-652-11. ↑

  5. Evert CR, Gijben M. 2017. Official South African Lightning Ground Flash Density Map 2006 to 2017. ↑

  6. Source: http://pveducation.org/pvcdrom/modules/nominal-operating-cell-temperature. ↑

Installation & User Manuals

PowerOptimal Elon 100 Installation Manual v1.40 (Elon 100 units pre-2019)

A black and yellow text Description automatically generated

PLEASE NOTE: This manual is for old Elon® 100s up to August 2019.

See https://poweroptimal.com/manuals/ for manuals & guides for new Elons from September 2019 onwards.

(How do I know if I have an old or new Elon® 100? The controller for the old version says “Efficiency” below the dial (knob), whilst the controller for the new version has “Turn anticlockwise to increase solar hours” below the dial.)

Version date: 2019/09/19

embedded-image-abwgjrpu.png

SAFETY WARNING

embedded-image-1019sxlz.pngRefer to the PowerOptimal website for the Elon 100 User Manual: www.poweroptimal.com/manuals

Table of Contents

1. Required tools 

2. Basic wiring diagram

3. Solar PV array installation

4. Elon 100 installation

5. Element installation (retrofit) 

Appendix A. Solar yield 

A1. Solar irradiance levels 

A2. Geographic features 

A3. Azimuth / horizontal angle 

A4. Inclination or tilt angle

A5. Shading 

A6. Ambient temperature 

Appendix B. Deciding on Size of Solar Array 

Appendix C. PV array and geyser (water heater) element matching 

Appendix D. Technical Specification Summary: Elon 100

Appendix E. IEC/SANS Test Certificate: Elon 100 

Appendix F. Warranty 

Appendix G. Terminology

Notes 

1. Required tools

The following tools are required for the installation. Use insulated tools wherever applicable.

2. Basic wiring diagram

embedded-image-6d7wmwvm.png

Note: Both AC & DC circuit breakers should be installed within 1.5m of the geyser (water heater), line of sight.

3. Solar PV array installation

Modules should only be installed by a trained solar PV installation technician. Array position and orientation have a major impact on power production (see Appendix A).

Review the instructions from your solar PV module supplier / manufacturer on installation.

embedded-image-bzfu0toa.png

Please note: A South African standard for low voltage embedded generation installations is being developed (SANS 10142:3). In the absence of this standard, your solar PV installation technician should follow SANS 10142:1 (Standard for low voltage installations) as always, and can refer to interim guidelines in anticipation of the SANS 10142:3 standard – see for example the document provided by PQRS:

http://pqrs.co.za/wp-content/uploads/2016/01/PV-System-Interim-Guidelines-Good-Practice-for-Solar-PV-Installations-South-Africa-.pdf

SAPVIA (South African Photovoltaic Industry Association) has made available an excellent guide to solar PV installations. See:

https://www.pvgreencard.co.za/Solar%20PV%20Guidelines%20-%20Digital%20‌Spread%20High-res.pdf

NB: Refer to Appendices B & C for guidelines on selecting the right size solar PV array for the user requirements, and for correctly matching the solar PV array and the geyser element.

The below installation steps are a general guide only – refer to the abovementioned standards and guidelines.

  1. A very important starting point is safety gear: ensure that all installers wear a helmet and insulated safety gloves, as well as fall protection safety gear if work will be done on a roof or elevated area.
  2. The solar PV array should only consist of one string of 3 to 6 modules (60-cell) or 3 to 5 modules (72 cell) in series, or two parallel strings of 8 (2 x 4) or 10 (2 x 5) modules. Do not exceed the DC voltage or current ratings of the Elon 100 (220V DC and 20A DC) under any circumstances.
  3. Attach bracket / mounting structure to roof. Use mounting structure recommended by solar module supplier for roof type and size of solar modules.
  4. Fix the solar PV modules to the mounting structure whilst connecting the module cables to each other.
  5. If practical, cover the modules to ensure that there is no potential for electric shock whilst installing the system.
  6. Ground the mounting structure only.
  7. Install the wiring from the solar PV array to the Elon 100 unit in the ceiling space. Ensure circuit breakers / isolators are in the “Open” position. Installation of a Surge Protective Device (SPD) between the solar PV array and the Elon 100 is recommended.
  8. Last step is to connect the array to the rest of the wiring, making sure that both the positive and negative wires are fully isolated from ground and keeping circuit breakers / isolators in the “Open” position.

Some “DO’s & DON’T’s” when installing solar PV arrays:

Your solar PV installer should not make any of these basic mistakes, but they are listed here just in case.

  1. DO earth the PV array structure.
  2. DO isolate the wires from the PV array structure.
  3. DON’T use different sizes, types or specifications of modules together in the same string or array.
  4. DON’T install solar arrays where they will be partially shaded during any season of the year if it can be avoided at all.
  5. DO install the arrays so that there is space for inspection or maintenance when needed.
  6. DO use cabling of the correct size for your solar array.
  7. DON’T install the solar array flush with your rooftop. Use struts / brackets that ensure an unrestricted air gap of at least 40 mm between the roof and the modules.
  8. DON’T walk on the modules.
  9. DO ensure that connectors are kept clean and away from water.
  10. DON’T leave exposed modules in short circuit.
  11. DO ensure that all connectors are securely fastened.
  12. DON’T exceed the voltage ratings of any components.
  13. DO properly route and secure all cables.
  14. DON’T coil cables.

4. Elon 100 installation

  1. Isolate the geyser – switch off the geyser circuit breaker at the main electrical distribution board (DB) AND switch off the geyser isolator at the geyser.
  2. Confirm with a multimeter that there is no voltage across the wires.
  3. Install circuit breaker (or isolator and fuse) for solar PV (DC) supply. Also install AC supply isolator / circuit breaker if there is none. NB Ensure that the DC circuit breaker is rated for the DC voltage and current of the installed solar PV array.
  4. The circuit breakers / isolators must be installed within 1.5m of the geyser, and must be line of sight / visible (i.e. do not install them at the back of the geyser).
  5. The DC wires must not be earthed – i.e. they must be fully isolated from earth. Do NOT test with a Megger.
  6. Keep the DC wires as short as possible.
  7. Avoid any coils in DC wires.
  8. Recommended wiring size is at least 2.5 mm². Use panel wire for all connections to the Elon 100.
  9. Install the Elon 100 unit according to wiring diagram (see Section 2).
    1. Mount the Elon 100 unit close to the geyser and protect from outside elements.
    2. Mount the controller (remote control) inside or next to the main DB in the house or in another convenient and accessible location (for example the garage). Double-sided mounting tape and Genkem contact adhesive work well for most surfaces.
    3. Connect the Elon 100 and thermostat last.

embedded-image-lh6e2ocy.pngembedded-image-dcnzfjqn.png

Note: As per the wiring diagram, the thermostat and element should be connected to the Elon SEPARATELY (independently). For TSE and Thermowatt (RTS) thermostats, connect the Elon directly to the two screw terminals and short the two male terminals at the bottom together, using the bridging wire with female connectors supplied with the Elon 100 (see photos above). (Less then 20 mA DC current will flow through this wire – it is a sensing current only.) There must be no connection between the thermostat and the element.

10. Connect the two element terminals directly to the connectors marked “element” on the Elon. For flange-type elements, use the supplied wiring with element adapter (see photos below). For many elements, the female terminals are sunk too deep in the plastic cover, leading to poor connectivity. If this is the case, trim the tops of the plastic cover on the element so that it is flush with the tops of the female terminals. Make sure that the element adapter fits tightly into the element and that the two male connectors of the adapter are slotted correctly into the female terminals of the element. Crimp both terminals (you can do this through the plastic cover) to ensure a tight fit on both sides.

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11. Slide the thermostat (with bridging wire installed) into the pocket in the element as deep as it can go.

12. Set the thermostat to the desired temperature (55 °C maximum).

13. Attach installation diagram sticker (as provided) close by the geyser in a clearly visible position. (Do not attach it directly to the geyser, as it will disappear if the geyser is replaced.)

14. Once installation is complete, do the following:

    1. Turn the control dial to "SOLAR ONLY".
    2. Switch on the AC & DC circuit breakers or isolators
    3. Remove the covering from the solar modules
    4. Switch on the geyser circuit breaker at the main DB.

15. Check that Elon 100 unit is operational (refer to LED lights on controller – see below).

    1. Confirm solar PV array supply voltage and DC power to geyser when thermostat is closed. The Elon 100 will switch DC power to the geyser approximately 10 to 15 seconds after DC power to the Elon has been switched on (if there is enough sunlight). (If thermostat is not closed, open hot water tap in house until it closes.)
    2. Test mains override by pressing and holding the override button for 5 seconds. The red light should start flashing (except if geyser is already at thermostat setpoint temperature). NOTE THAT THE ELON WILL NOT SWITCH TO MAINS WITHIN 5 MINUTES OF MAINS POWER SWITCH-ON OR RECONNECTION. This is to allow grid power to stabilize after a power failure.
    3. Confirm that no power is supplied to geyser element when thermostat is open (turn thermostat set point to lowest setting).

16. Set controller dial to desired control position (6 o’clock is good for an initial setting).

Note: if doing any maintenance, rewiring or disconnecting the Elon 100 or geyser element for any reason, it is good practice to first switch off both the AC & DC circuit breakers / isolators, and then disconnect one of the wires between the Elon 100 and thermostat before disconnecting the rest of the wires.

The Mains & solar indicator lights indicate the following conditions:

Installation manual v1-40 controller lights.png

Controller settings for switching off solar or grid power to electric geyser

Installation manual v1-40 controller dial settings.png

5. Element installation (retrofit)

If you need to exchange the element on an existing geyser, please follow the instructions provided by the element supplier.

There are two main types of geyser heating elements: screw-in and flange type. There are also two main types of thermostats: VKF-11 and TSE. The below table provides a guide to Elon compatibility with the different elements and thermostats.

Element type

Compatible thermostat type

Comments

Screw-in element:

 

Image result for screw-in geyser element

VKF-11 thermostat:

Image result for vkf11 thermostatImage result for vkf11 thermostat

Element & thermostat have separate electrical connections, so each can be connected (wired) separately to the Elon. Thus, this element-thermostat combination is directly compatible with the Elon. (No need to use the bridging wire or element adapter supplied with the Elon unit.)

The thermostat pocket in the element is the right size for the VKF-11 thermostat.

Spiral element (flange type) with smaller diameter thermostat pocket:

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TSE thermostat: Thermowatt (RTS) thermostat:

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The spiral element generally has a smaller thermostat pocket than the screw-in element. The TSE and Thermowatt (RTS) thermostats fit into this smaller pocket. The VKF-11 thermostat requires a larger pocket and does not fit into standard spiral element pockets.

The TSE and Thermowatt thermostats normally clip directly into the element, but this won’t be the case when the Elon is connected.

Use the bridging wire and element adapter supplied with the Elon (see Figures 4.1 to 4.4 above) to connect the Elon to these thermostats and elements.

 

Appendix A. Solar yield

Note: only basic information is provided here. Your solar PV installation technician should advise on the best configuration for your specific location, roof structure, etc.

The yield produced by solar PV modules depends on a number of factors:

A1. Solar irradiance levels

SolarGIS_GHI_South_Africa_width15cm_300dpi (CRSES)The map below shows the general solar irradiance levels (GHI or Global Horizontal Irradiance) in South Africa[1]:

You can expect the following approximate energy generation from solar modules for various locations[2]:

Location

Electricity generated kWh/kWp per year

Bloemfontein

2055

Cape Town

1762

Durban

1570

Johannesburg / Pretoria

1871

Mbombela

1766

Port Elizabeth

1698

Upington

2075

A2. Geographic features

embedded-image-xgbybevx.pngMajor geographical features (such as hills or mountains) can reduce the total solar yield.

A3. Azimuth / horizontal angle

The azimuth refers to the horizontal orientation of the modules – in the Southern Hemisphere, by how many degrees they are oriented away from north

Due north is best in the Southern hemisphere. Modules should preferably not be oriented more than 15º away from due north.

A4. Inclination or tilt angle

The tilt angle refers to the vertical orientation of the modules – a rough guide is that the modules should be tilted at the site’s latitude. For example, Musina is 22º S, Pretoria & Johannesburg are 26º S, Bloemfontein is 29º S, Durban is 30º S and Cape Town & Port Elizabeth are 34º S. To optimise winter performance, one can add 15º to the tilt angle. (Note: as long as you are within about 15º of the optimal latitude, the loss in efficiency is not substantial.)

A5. Shading

Solar modules lose a lot of efficiency if even a small part of the module is shaded. For example, just 3% shading can cause a 25% loss in power! Shaded cells on a module also causes hotspots, which will reduce module lifetime.

It is thus important to place the solar modules on a rooftop area that is free from shading for as much as possible of the day (and throughout the year).

A6. Ambient temperature

Solar PV modules’ performance decreases with increasing temperature. Wind will reduce the temperature of the solar array and will thus improve performance. Thus, it is important to install rooftop solar modules with an air gap of at least 40 mm between the modules and roof[3].

Appendix B. Deciding on Size of Solar Array

Terminology used

http://ohioline.osu.edu/sites/ohioline/files/AEX_652_11.pdf-1_13.jpg

Solar power is generated by solar cells, which are arranged in framed modules, typically of 60 or 72 cells each. The total set of solar PV modules installed is referred to as a solar PV array[4].

The table below provides a basic guide to selecting the size of the Elon system based on number of people in the household and/or hot water use. Read on for a more detailed guide.

PowerOptimal Elon® 100 kit easy selection guide V2.13 - slide 2.png

TABLE B1. ANNUAL AVERAGE LITRES OF WATER HEATED PER DAY

The below example table indicates the average number of litres of water per day that the system will heat from 15 to 60 °C over a year period for different solar array peak power ratings. (The amount of water heated will vary with weather conditions, by geographic location and by season. Water heated per day will be significantly lower in winter and significantly higher in summer. These numbers indicate heating capacity – i.e. if no hot water is used on a given day, there will be less water heated on that day. This is only an approximate guide.)

Installation manual Table C1.png

Example:

For a solar array of 1.2 kWp, an installation in Johannesburg would yield about 1724 kWh/kWp/yr, or 1724 x 1.2 kWp = 2069 kWh/yr. This would be sufficient to heat on average 109 litres of water per day. For a family of 2 each using 80 litres of hot water per day, this would provide about 109 ÷ (80 x 2) or 68% of the annual hot water requirement.

TABLE B2. ANNUAL AVERAGE NUMBER OF SHOWERS PER DAY

The below table indicates the average number of showers per day for which the system will supply hot water over a year period for different solar array peak power ratings. (The amount of water heated will vary with weather conditions, by geographic location and by season. Water heated per day will be significantly lower in winter and significantly higher in summer. These numbers indicate heating capacity – i.e. if no hot water is used on a given day, there will be less water heated on that day. This is only an approximate guide.)

Installation manual Table C2.png

The table is based on 6-minute showers at 40 °C and 8 litres/min low flow showerheads. Old showerheads can use up to 15 litres/min and would substantially reduce the number of showers.

Example:

For a solar PV array of 2.5 kWp, an installation in Johannesburg would yield about 1724 kWh/kWp/yr, or 1724 x 2.5 kWp = 4 310 kWh/yr. This would be sufficient for about 6 to 7 showers per day.

TABLE B3. PERCENTAGE OF ANNUAL HOT WATER REQUIREMENT

The below example table indicates what % of the annual hot water requirement will on average be supplied by the system for 2 people each using 80 litres of hot (60 °C) water per day. (The amount of water heated will vary with weather conditions, by geographic location and by season. Water heated per day will be significantly lower in winter and significantly higher in summer. These numbers indicate heating capacity – i.e. if no hot water is used on a given day, there will be less water heated on that day. This is only an approximate guide.)

Installation manual Table C3.png

Examples:

An array of 1.2 kWp will provide approximately 64% of the annual hot water requirement for a family of two people in Cape Town.

An array of 2 kWp will provide approximately 124% x (4 / 2) = 62% of the annual hot water requirement for a family of four people in Bloemfontein.

TABLE B4. PEAK POWER OUTPUT FOR VARIOUS SOLAR MODULES AND ARRAY SIZES

The peak power production (Wp) of the modules at STC (Standard Test Conditions) and at NOCT (Nominal Operating Cell Temperature) are provided by the solar PV module manufacturer. The below table indicates the peak power at STC for a range of solar module power ratings and array sizes.

No. of cells per module

Module STC power rating (Wp)

Total peak power at STC in kWp for an array of X modules

3 modules

4 modules

5 modules

6 modules

2 x 4 (8) modules

2 x 5 (10) modules

2 x 6 (12) modules

60

250

0.75

1.00

1.25

1.50

2.00

2.50

3.00

60

255

0.77

1.02

1.28

1.53

2.04

2.55

3.06

60

260

0.78

1.04

1.30

1.56

2.08

2.60

3.12

60

265

0.80

1.06

1.33

1.59

2.12

2.65

3.18

60

270

0.81

1.08

1.35

1.62

2.16

2.70

3.24

60

275

0.825

1.10

1.375

1.65

2.20

2.75

3.30

60

280

0.84

1.12

1.40

1.68

2.24

2.80

3.36

60

285

0.855

1.14

1.425

1.71

2.28

2.85

3.42

60

290

0.87

1.16

1.45

1.74

2.32

2.90

3.48

72

295

0.885

1.18

1.475

1.77

2.36

2.95

3.54

NOT ALLOWED

(exceeds maximum rated Elon 100 voltage)

72

300

0.90

1.20

1.50

1.80

2.40

3.00

3.60

72

305

0.915

1.22

1.525

1.83

NOT ALLOWED

(exceeds maximum rated Elon 100 voltage)

2.44

3.05

3.66

72

310

0.93

1.24

1.55

1.86

2.48

3.10

3.72

72

315

0.945

1.26

1.575

1.89

2.52

3.15

3.78

72

320

0.96

1.28

1.60

1.92

2.56

3.20

3.84

72

325

0.975

1.30

1.625

1.95

2.60

3.25

3.90

72

330

0.99

1.32

1.65

1.98

2.64

3.30

3.96

72

335

1.005

1.34

1.675

2.01

2.68

3.35

4.02

72

340

1.02

1.36

1.70

2.04

2.72

3.40

4.08

Examples:

An array of 4 x 300 Wp modules in series will have a total peak power (at STC) of 1.2 kWp.

An array of 2 parallel strings of 5 modules of 280 Wp each (10 modules of 280 Wp in total) will have a total peak power (at STC) of 2.8 kWp.

Appendix C. PV array and geyser (water heater) element matching

TABLE C1. PV ARRAY AND GEYSER (WATER HEATER) ELEMENT MATCHING

It is important to match PV array specifications and heating elements for maximum power transfer efficiency. See the below table for the recommended heating element power rating for different solar module power ratings and array sizes.

PowerOptimal Elon® 100 kit easy selection guide V2.13 - slide 1.png

DO NOT DEVIATE FROM THE RECOMMENDED ARRAY-ELEMENT MATCHING CONFIGURATIONS WITHOUT CONSULTING POWEROPTIMAL.

Appendix D. Technical Specification Summary: Elon 100

Refer to the PowerOptimal website for the full Technical Specification www.poweroptimal.com/specifications

Rated input voltage

250V AC, 220V DC

Rated input current

25A AC, 20A DC

Mains (AC) voltage range

-50% to +100% (but will disconnect all loads when breach is greater than +/- 15%)

System power supply

Solar or 230V AC mains

Shutdown

Sufficient power supply capacity to manage processor, switching and data storage if both mains and solar supply fail

Solar voltage

20 – 220 V DC

Solar energy availability

Automatically determines availability of sufficient solar energy before supplying load from solar modules

Efficiency control

Can be adjusted to run from “solar only” to substantial AC mains power usage

Override switch

A request (override) switch to force the managed load to use AC mains for one heating cycle is provided

Thermostat

Uses the standard normally open thermostat switch associated with the geyser element as a sensor only, with less than 10mA sense current, to control power to the element

Reverse polarity protection

Protected against reverse connection of solar array

Switching timing

Built-in random numbers generation staggers switching times where more than one Elon 100 is deployed

Enclosure ingress protection rating

IP65

Annual energy production compared to inverter-based system

> 90% when solar array and geyser element are matched correctly

It is important to match modules and heating elements for maximum power transfer efficiency. See the tables in Appendix C for the recommended heating element power rating for different solar module specifications and array configurations.

Appendix E. IEC/SANS Test Certificate: Elon 100

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Appendix F. Warranty

If the PowerOptimal ElonTM 100 (“the Product”) is found to be defective, you will be entitled to a repair or replacement within 2 (two) years of the date of delivery of the Product to you. Please keep your receipt as proof of purchase. If you are a consumer as defined in the Consumer Protection Act No. 68 of 2008 (“the CPA”), you will be entitled to such remedies as are made available under the CPA in relation to the return of goods.

PowerOptimal will not have any liability or obligation to you where the Product has been subjected to abuse, misuse, improper use, improper testing, negligence, accident, alteration, tampering or repair by a third party.

To the maximum extent permitted by applicable law, in no event shall PowerOptimal be liable for any special, incidental, indirect, or consequential damages whatsoever, including, without limitation, damages for loss of business profits or business interruption, arising out of the use or inability to use this product.

Please note that this unit must be installed by an electrical contractor registered with the Department of Labour. Failure to do so may invalidate this warranty.

Appendix G. Terminology

AC Alternating Current – an electric current that reverses its direction many times a second at regular intervals, with voltage typically varying in the form of a sine wave.

CoC Certificate of Compliance – to be issued by the electrician installing your Elon 100 system

CPA Consumer Protection Act No. 68 of 2008

DB Distribution board – the main electrical distribution board / panel in your home, containing circuit breakers and switches.

DC Direct Current – an electric current flowing in one direction only. Solar PV modules produce direct current electricity.

Geyser South African term for a water heater

IEC International Electrotechnical Commission

Impp The solar module current at maximum power point (MPP). Manufacturers usually report two Impp values: one at STC and one at NOCT.

kWh A derived unit of energy equal to 3.6 MJ (megajoules). The amount of energy used by a 1 kW electrical device over a period of 1 hour.

kWp or Wp The peak power rating in kilowatt (kW) or watt (W) of a solar module or array – i.e. the output power achieved under full solar radiation. This is usually reported at STC and NOCT.

MPP Maximum power point. This is the point on a solar cell, module or array’s power or I-V (current-voltage) curve that has the highest power output.

NOCT Nominal Operating Cell Temperature. This refers to the temperature that open circuited solar PV modules will reach under conditions that more closely match actual field operational conditions than STC. The modules are tested at 800 W/m² simulated solar irradiance, 20 °C ambient temperature, 1 m/s wind velocity and open back side mounting. Depending on the quality of the cell / module design, the NOCT can reach anything from 33 to 58 °C[5]. Since solar PV cell power output reduces with increase in temperature, a lower NOCT is better.

PV Photovoltaic – referring to the production of electric current at the junction of two materials exposed to light.

SANS South African National Standards

STC Standard Test Conditions for solar cells – 1000 W/m² simulated solar irradiance and 25 °C solar cell temperature, and an air mass 1.5 spectrum (AM1.5).

Vmpp The solar module voltage at maximum power point (MPP). Manufacturers usually report two Vmpp values: one at STC and one at NOCT.

Notes

  1. CRSES (Centre for Renewable and Sustainable Energy Studies). Website: http://www.crses.sun.ac.za/files/research/publications/SolarGIS_GHI_South_Africa_width15cm_300dpi.png. Last accessed: 07/04/2017. ↑

  2. Urban Energy Support. Website: http://www.cityenergy.org.za/uploads/resource_274.pdf. Last accessed: 07/04/2017. ↑

  3. D’Orazio M et al. 2013. Performance assessment of different roof integrated photovoltaic modules under Mediterranean Climate. ↑

  4. Image source: http://ohioline.osu.edu/factsheet/AEX-652-11. ↑

  5. Source: http://pveducation.org/pvcdrom/modules/nominal-operating-cell-temperature. ↑

Installation & User Manuals

PowerOptimal Elon 100 User Manual v1.40 (Elon 100 units pre-2019)

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PLEASE NOTE: This manual is for old Elon® 100s up to August 2019.

See https://poweroptimal.com/manuals/ for manuals & guides for new Elons from September 2019 onwards.

(How do I know if I have an old or new Elon® 100? The controller for the old version says “Efficiency” below the dial (knob), whilst the controller for the new version has “Turn anticlockwise to increase solar hours” below the dial.)

Version date: 2019/07/02

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SAFETY WARNING

Refer to the PowerOptimal Elon 100 Installation Guide at www.poweroptimal.com/manuals for detailed installation information.

embedded-image-uymcyorv.pngYou can find an easy-to-understand Quick Reference User Guide for download from: www.poweroptimal.com/manuals

You can also watch an online instruction video for instructions on how to use the PowerOptimal Elon® 100:

Image result for play button orange

www.poweroptimal.com/elon100

Table of Contents

Table of Contents

1. Introduction

1.1 System overview

1.2 Main system components

1.3 Deciding on size of Elon system (basic guide)

2. Operation

2.1 Elon 100 controller

2.2 Mains / solar indicator lights

2.3 Efficiency dial

2.4 Override button

2.5 Controller settings for switching off solar or grid power to electric geyser

2.6 How to maximise your savings

3. Maintenance

3.1 Solar PV module maintenance

4. What to expect in terms of performance

4.1 Hot water production

4.2 Impact of location and seasons

4.3 Payback period

5. Troubleshooting

Appendix A. IEC/SANS Test Certificate: Elon 100

Appendix B. Warranty

Appendix C. Terminology

Notes 21

1. Introduction

Thank you for buying the PowerOptimal ElonTM 100 solar PV water heating unit! You can look forward to many years of savings and free energy from the sun.

1.1 System overview

The PowerOptimal Elon 100 operates on a very simple principle: it enables direct current (DC) electricity produced by solar PV modules to be used directly for water heating using a standard geyser with alternating current (AC) heating element and AC thermostat, with no need for an inverter. It uses the water in your geyser as a battery to store solar energy in the form of heat.

You can connect the system completely off-grid, or connect it to your existing grid AC power supply. Connecting the system to the existing grid supply allows for grid power backup in case of cloudy / overcast days, or where your hot water use exceeds the generation capacity of your solar PV array.

Note: the system is designed in such a way that there is no possibility of solar array-produced electricity feeding back into the grid.

Below is a simplified layout of the main components of the water heating system.

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An array of solar modules (a string of 3 to 6 solar modules connected in series, or two parallel strings of 4, 5 or 6 solar modules each) is connected to the Elon 100. Grid electricity is also connected to the Elon 100.

The Elon 100 is connected to the geyser element and thermostat.

When the solar modules are producing electricity, the Elon 100 feeds this into the geyser element to heat water, until the water reaches the temperature setting on the thermostat.

Depending on the Elon 100 efficiency setting (see Section 2.3) or when the user presses the override button, the Elon 100 will boost the water heating with grid electricity.

1.2 Main system components

The main components of the system are as follows:

1.3 Deciding on size of Elon system (basic guide)

The table below provides a basic guide to selecting the size of your Elon system based on number of people in the household and/or hot water use. The Installation Manual (which you can download from www.poweroptimal.com/manuals) contains a more detailed guide.

PowerOptimal Elon® 100 kit easy selection guide V2.13 - slide 2.png

2. Operation

Image result for play button orange

Instruction video: www.poweroptimal.com/elon100

Refer to our easy to understand instruction video on how to use the Elon 100.

2.1 Elon 100 controller

User manual v1-40 controller aspects.png

Your Elon 100 has a controller that is typically installed next to your DB (distribution board). The controller has three main functions:

  1. Indicating heating activity through the mains (red) & solar (green) indicator lights (Section 2.2)
  2. Setting the timing on the efficiency dial (Section 2.3)
  3. Forcing the system to use grid (mains) electricity for one heating cycle using the override button. (Section 2.4)

2.2 Mains / solar indicator lights

The Mains & solar indicator lights indicate the following conditions:

Installation manual v1-40 controller lights.png

2.3 Efficiency dial

User manual v1-40 efficiency dial.png

Turn the dial on the controller to set how much of the day the unit will run on solar power only (see the diagram above). It is generally best to just leave it pointing straight down.

The best setting for you will be determined by your hot water use habits and the number of solar PV panels installed.

At all dial settings except “Solar only”, the Elon 100 will switch off grid power to the geyser early in the morning. You will start with hot water in the geyser, but as you use it, the temperature will gradually drop, so that the geyser is ready to be heated by the sun during the day.

The dial determines at approximately what time the Elon will switch back to grid power, as shown in the diagram above.

At the “MINIMUM” efficiency setting, the Elon 100 will switch back to grid power around 11 am or 12 pm. As you turn the dial anti-clockwise, the time that the Elon 100 will switch back to grid power moves later and later in the day. This will give the solar power supply more time to heat the water before boosting with grid power.

So if you only use hot water early morning and in the evenings, you can set it close to “Solar only” to benefit from a longer solar energy heating period.

When the efficiency dial is set to “SOLAR ONLY”, the Elon 100 will ONLY use solar power to heat water.

Note that the override button is still functional at the “SOLAR ONLY” setting, in case you need to boost water heating on a cloudy day or when using a lot of hot water.

If you set the Elon efficiency setting to “SOLAR ONLY” (highest efficiency), you can increase the geyser thermostat temperature to 60 ºC to get maximum benefit from your solar array installation. We do not recommend setting the thermostat temperature above 60 °C. Remember to reduce the thermostat temperature again if you reduce the efficiency setting.

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Warning: Do not set thermostat temperature above 65 ºC due to increased scalding risk. Be careful when opening hot water taps located close to your geyser. You can install a thermostatic mixing valve to reduce the risk of scalding – ask your plumber.

2.4 Override button

If you would like to override the functioning of the Elon 100 and force it to use grid power for water heating (for example in case of prolonged cloudy weather, or having used a lot of hot water), press and hold the override button for 5 seconds.

This will force the Elon 100 to switch to grid (mains) power for one heating cycle (in other words, it will the water with grid electricity to the thermostat set point from whatever temperature it is at the time of pressing the override button).

Only the red mains light on the controller should start flashing at this point. (If both red and green lights are flashing (alternating), the water is already at the thermostat set point, and pressing the override button will have no effect.)

To switch off solar power completely, press and hold the override button for 15 seconds. The red mains light will come on permanently. This means that the system is heating water with mains power 24 hours a day. To switch the solar power back on, again press and hold the override button for 15 seconds.

2.5 Controller settings for switching off solar or grid power to electric geyser

Desired state

Actions

DB board geyser switch

Controller dial position

Lights

✓ Solar ON

✓ Grid ON

This is the default state.

ON

Anywhere outside the “Solar Only” zone

Normal operation (green and/or red flashing or both alternating)

✓ Solar ON

🗶 Grid OFF

Turn controller dial anti-clockwise to the “Solar Only” zone indicated on the controller. Note: can still boost with grid power for one heating cycle by pressing the Override button for 5s.

ON

In the “Solar Only” zone

Green flashing or both lights alternating. Red would flash if override button has been used.

🗶 Solar OFF

✓ Grid ON

Press Override button for 15s until the red light switches on permanently. Grid power is now always ON (24 hours per day).

ON

Anywhere outside the “Solar Only” zone

Red light on

🗶 Solar OFF

🗶 Grid OFF

Turn efficiency dial all the way anti-clockwise into the "Solar Only" zone. Press Override button for 15s until the red light switches on permanently.

ON

In the “Solar Only” zone

Red light on

2.6 How to maximise your savings

Efficiency dial

The best way to maximise your savings is to set the Elon efficiency dial to “SOLAR ONLY”. This will ensure that the unit will never use grid (mains) power for heating water. You can still override / boost with mains power (for example on a cloudy day) using the override button as described above.

If you do not have enough solar power for the number of people and overall level of hot water use in the household, you might not reach the desired water temperature with the “SOLAR ONLY” setting, and might need to reduce the efficiency setting, or reduce your hot water use.

Please note: The water in your geyser should be heated to 60 °C at least once a week to prevent Legionella bacterial growth[1]. If you have heavily overcast weather for more than a week, use the override button to supplement the solar water heating with grid electricity to reach the thermostat temperature setting.

When is the best time to shower?

If the efficiency dial is set to “SOLAR ONLY”, it is best for people in the household to shower either in the morning or in the evening, but not both. (If you shower in the evening, cold water will mix with the remaining warm water overnight, and you will have cold water the next morning. If you do not shower again in the morning, the water will be heated during the day.)

If the efficiency dial is set to lower efficiency than “SOLAR ONLY”, it is best to shower in the morning for maximum savings.

Going on holiday

If you are going on holiday, you don’t need to switch off the solar power supply to your geyser. It will continue to maintain water temperature and prevent or minimize Legionella bacteria growth. As a plus you will have hot water in your geyser when you return from holiday!

You can switch off the mains power supply to the geyser in one of two ways: (1) turn the Elon 100 efficiency dial to solar only (anti-clockwise to end position); OR (2) switch off the geyser circuit breaker in your electrical distribution board (DB). We recommend option 1.

If you do want to switch off both the solar and mains power supply to your geyser, turn the Elon 100 efficiency dial to solar only (anti-clockwise to end position), then press and hold the override button for 15 seconds (until the red light comes on permanently). Don’t switch off the circuit breaker at the DB board. (When you return, set the efficiency dial in its normal position, then press and hold the override button for 15 seconds until the red light switches off or starts flashing.)

General hot water energy saving tips

South Africa is a water-scarce country – reducing hot water use saves both energy and water!

3. Maintenance

The Elon 100 has been designed to last for a very long time, and has no moving parts aside from two electrical relays. No maintenance is required on the Elon 100.

3.1 Solar PV module maintenance

  1. At least once a week, check whether any of the indicator lights are flashing rapidly. (This indicates an isolation fault – refer to Section 3.2.)
  2. Perform regular visual checks (at least once a year). Check for soiling or any visible damage to any of the modules.
  3. If the modules have been soiled by dirt, dust, debris, bird droppings or any other materials, use water only and a sponge or soft cloth to clean them. Do the cleaning early in the morning or late in the afternoon, as the modules are hot during the day. Avoid using a water jet that may leave streaks on the modules.
  4. Visually inspect cables for any degradation or loose fittings.
  5. Look for any shading problems, such as trees that may have grown.
  6. An electrician can check solar power production on a sunny day to ensure that the system is still producing power at expected levels. A thermal imaging camera can be used to inspect modules for hot spots.
  7. Follow any specific maintenance instructions from the solar PV module manufacturer.

4. What to expect in terms of performance

4.1 Hot water production

Heating water takes a LOT of energy. A household geyser can use up to 40% of a house’s electricity. Heating a single 200 litre geyser from 15 °C to 60 °C will use over 10 kWh. This is about the same amount of energy burnt by a person running a distance of over 100 km at 10 km/hr, or enough energy to watch more than 120 hours of TV[2].

The more solar panels you have on your roof, the faster the Elon 100 system will heat your water. Typically, the number of panels has been selected to heat water over most of the sunlight hours (from morning to afternoon). This will be slower than heating water using grid electricity. So you can expect a gradual temperature rise from morning to afternoon.

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As one would expect, hot water production increases with increase in number of solar panels. Keep in mind that these numbers are averages over the year. This means that you should expect a lower number in winter and a higher number in summer.

4.2 Impact of location and seasons

The amount of energy from the sun depends on your location, the time of year as well as the orientation of your solar panels. The best direction for panels in South Africa is to face north, at an angle of about 25 to 35° from horizontal.

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Although Gauteng (Johannesburg / Pretoria) & Cape Town may seem quite similar in terms of total solar energy per year, Cape Town has winter rainfall and Gauteng has summer rainfall. This leads to Cape Town having much lower solar electricity production than Gauteng in winter.

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4.3 Payback period

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As can be seen from the graph above, payback period decreases as number of solar panels increases, and is also different for Johannesburg, Cape Town and Durban[3].

The reason that payback period improves (decreases) as number of solar panels increases, is because there are some fixed costs (such as engineering design & safety components) and some costs that do not scale linearly with array size (such as labour, wiring, mounting kit costs, etc.).

5. Troubleshooting

Below is a table with basic troubleshooting tips. If you cannot resolve the problem using the below table, please contact your installer.

Issue

Possible causes

What to do

Water temperature too low
  1. High hot water usage levels
  2. Cloudy or rainy day
  3. Dirty solar modules
  4. Mains circuit breaker has tripped
  5. Thermostat connection or thermostat defective
  1. Press override button (3.3) OR

Reduce efficiency setting (3.2) OR

Reduce hot water use (3.5) OR

Add additional solar modules to your solar installation (first consult with your installer)

  1. See a. above
  2. Inspect solar modules. If they are soiled, clean them with water and sponge (4.1)
  3. Check mains circuit breaker
  4. Call electrician for inspection

Water temperature remains low after mains power boost
  1. Sufficient time has not been provided for water to be heated after override button has been pressed
  2. It is a cloudy day and there is a mains power failure
  3. There is an electrical fault or the Elon 100 is defective
  4. Thermostat connection or thermostat defective
  1. Wait for 2 hours after pressing the override button
  2. You will have to wait until either the solar or grid power returns to heat the water
  3. Check if only the mains light on the Elon 100 controller starts flashing after you press the override button for 10 seconds. If it does not and your water remains cold, call your electrician to inspect the installation for any electrical fault.
  4. Call electrician for inspection

Water temperature too high
  1. Thermostat temperature setting is high and you are using hot water from a tap close to the geyser
  2. Thermostat connection or thermostat defective
  1. Reduce thermostat temperature set point OR

Open the cold water tap first

OR

Install a thermostatic mixing valve

  1. Call electrician for inspection.

Hot water production is lower than it used to be
  1. Dirty solar modules
  2. Trees / plants have grown and are causing shaded areas on solar modules
  3. Damage to solar modules
  1. Inspect solar modules. If they are soiled, clean them with water and sponge (4.1)
  2. Trim trees and plants
  3. Installer or electrician should test solar array power production in sunny conditions and compare with specifications. If one or more modules are damaged and they are still under warranty, contact manufacturer for replacement

Both indicator lights off
  1. Power failure and overcast / night-time
  2. Geyser breaker at DB board switched off
  1. Wait until power or sun returns and check if any indicator light comes on.
  2. Switch on breaker at DB board.

Red or green indicator light flashing very fast
  1. Isolation fault
  1. Please call your electrician.

 

Appendix A. IEC/SANS Test Certificate: Elon 100

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Appendix B. Warranty

If the PowerOptimal ElonTM 100 (“the Product”) is found to be defective, you will be entitled to a repair or replacement within 2 (two) years of the date of delivery of the Product to you. Please keep your receipt as proof of purchase. If you are a consumer as defined in the Consumer Protection Act No. 68 of 2008 (“the CPA”), you will be entitled to such remedies as are made available under the CPA in relation to the return of goods.

PowerOptimal will not have any liability or obligation to you where the Product has been subjected to abuse, misuse, improper use, improper testing, negligence, accident, alteration, tampering or repair by a third party.

To the maximum extent permitted by applicable law, in no event shall PowerOptimal be liable for any special, incidental, indirect, or consequential damages whatsoever, including, without limitation, damages for loss of business profits or business interruption, arising out of the use or inability to use this product.

Please note that this unit must be installed by an electrical contractor registered with the Department of Labour. Failure to do so may invalidate this warranty.

Appendix C. Terminology

AC Alternating Current – an electric current that reverses its direction many times a second at regular intervals, with voltage typically varying in the form of a sine wave.

CoC Certificate of Compliance – to be issued by the electrician installing your Elon 100 system

CPA Consumer Protection Act No. 68 of 2008

DB Distribution board – the main electrical distribution board / panel in your home, containing circuit breakers and switches.

DC Direct Current – an electric current flowing in one direction only. Solar PV modules produce direct current electricity.

Geyser South African term for a water heater

IEC International Electrotechnical Commission

kWh A derived unit of energy equal to 3.6 MJ (megajoules). The amount of energy used by a 1 kW electrical device over a period of 1 hour.

kWp or Wp The peak power rating in kilowatt (kW) or watt (W) of a solar module or array – i.e. the output power achieved under full solar radiation. This is usually reported at STC and NOCT.

PV Photovoltaic – referring to the production of electric current at the junction of two materials exposed to light.

SANS South African National Standards

Notes

  1. See for example: http://www.eskom.co.za/sites/idm/Documents/‌Legionaires_Fact_sheet‌_hot_water‌_bacteria‌_simple_facts.pdf and http://standards.nsf.org/apps/group_public/download.php/‌30413/How%20to%20Avoid%20LD%20at%20Home.pdf ↑

  2. 46” OLED TV at 82W. ↑

  3. Calculations based on actual Elon performance, assuming a 20% reduction due to non-optimal user behaviour, an initial electricity tariff of R2/kWh and an annual electricity price increase of 8%. ↑

Installation & User Manuals

PowerOptimal Elon® 100 Commissioning Checklist V1.02

Installation & User Manuals

PowerOptimal Elon® 100 Installation Checklist V1.03

Troubleshooting Guides

Troubleshooting Guides

Elon® 100 first line support checklist V2.4

Troubleshooting Guides

PowerOptimal Elon® 100 Troubleshooting Basics for Technicians v2.3

Troubleshooting Guides

PowerOptimal Elon® 100 Troubleshooting Guide for Electricians v2.12