PowerOptimal Elon® 100 User Manual v2.20

PowerOptimal Elon® 100 User Manual

Version number: 2.20

Version date: 2025/12/28

Enquiries: info@poweroptimal.com

Address: Postnet Suite 21

Private Bag X21

Tyger Valley

7536

Please note: Always check the PowerOptimal website for the latest version of this manual.

Patented: ZA2019/02129

SAFETY WARNING

• Installation of the Elon® 100 should ONLY be performed by an electrical contractor registered with the Department of Labour (the so-called “wireman’s licence”) and strictly according to the installation instructions in this manual. The electrician should provide you with a Certificate of Compliance (CoC) once installation is completed.
• We strongly recommend that you use a reputable and experienced solar photovoltaic (PV) system installer to install your solar PV modules.
• Solar PV modules exposed to the sun are live (i.e. will produce electricity) and can give an electric shock. Special care should be taken and only trained solar PV installers should install the modules.
• Do not attempt to alter or service the electrical installation, or open the Elon® 100 unit or controller for any purpose.
• Use the Elon® 100 only for its intended purpose.
• Always make sure that every wiring connection is properly tightened.
• Do not earth either of the solar module wires (but do earth the frames).
• All installation wiring should be at least 2.5mm².
• Avoid coiling, since DC switching can create damaging spikes.
• Keep all wires as short as possible.

Refer to the PowerOptimal website for the following:

Table of Contents

Table of Contents 3

1. Introduction 4

1.1 System overview 4

1.2 Main system components 5

1.3 Deciding on size of Elon® system (basic guide) 5

2. Operation 6

2.1 Elon® 100 controller 6

2.2 Mains and solar indicator lights 7

2.3 Control dial settings 8

2.4 Holiday settings 9

2.5 How to maximise your savings 10

3. Maintenance 11

3.1 Solar PV module maintenance 11

4. What to expect in terms of performance 12

4.1 Hot water production 12

4.2 Impact of location and seasons 13

4.3 Payback period 14

5. Troubleshooting 15

5.1 Troubleshooting Guide for Users 15

5.2 Troubleshooting Guide for Electricians 18

Appendix A. IEC/SANS and EMC Test Certificates: Elon® 100 19

Appendix B. Warranty 24

Appendix C. Terminology 25

Notes 26

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.

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:

• Solar modules with struts, brackets and cabling
• PowerOptimal Elon® unit with controller
• Existing or new water heater or geyser (hot water tank with AC heating element and AC thermostat)
• Isolators for grid and solar connections

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?

Solar PV array size (kWp)	Showers per day*	50%+ of daily hot water use provided for how many people?	How many people off-grid for hot water?	Typical number of solar PV modules
1 – 1.6				2 - 3 modules
1.6 – 2				3 - 4 modules
2 – 3				4 - 5 modules
3 – 4 (two parallel PV strings)				6 - 8 modules

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

WHAT SIZE GEYSER ELEMENT IS THE BEST MATCH?

* Second choice element size would reduce efficiency by 10 – 20%.

2. Operation

Instruction video: www.poweroptimal.com/elon100

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

2.3 Control dial

2.2 Mains & solar indicator lights

2.1 Elon® 100 controller

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)

1. 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:

2.3 Control dial settings

* Times are approximate – will vary slightly with season and location

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”:

• You have a large number of guests, and you want to ensure hot water for everyone at all times;
• You want to do maintenance on the DC (solar) side, but still want hot water;
• There is a problem on the DC side (e.g. an insulation fault), but you still want hot water;
• You are going away for a long time and don't want the water in the geyser to be heated up whilst you are away. (Then you would set the switch to "MAINS ONLY" and switch off the geyser at the main house DB – see Section 2.4 Holiday Settings).
• Any other reason you might want to turn the geyser heating off completely.

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.

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.

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.

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

• Shower, don’t bath
• Install water-saving / low flow shower heads (these also save energy because of reduced hot water use!)
• Reduce shower duration
• Check that your geyser is well insulated

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

It is recommended that a qualified electrician inspect your solar PV installation at least once a year.

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.

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.

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).

4.3 Payback period

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

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.

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

• The red mains LED will only start functioning once stable mains voltage between 160 and 260 V AC is present for more than 4 minutes. (In other words, the Elon® will only allow mains power to the element 4 minutes after mains connection or switch-on.)
• Solar power is only recognised 40 seconds after active solar panels are connected to Elon®.
• An open thermostat (water at correct temperature) measures between 11 and 14 V DC across the “thermostat” terminals on the Elon®. Polarity across these terminals is not important.
• A closed thermostat (cold water) measures 0 V across the “thermostat” terminals on the Elon®.
• How to switch on solar power to element: With enough solar energy (check at solar terminals), solar power will be routed to the element within 15 seconds after the thermostat closes and the controller dial is set to “SOLAR ONLY”. A green flashing LED indicates this condition.
• How to switch on mains power to element: Turn control dial to “MAINS ONLY” and, if the thermostat is closed, mains power will be directed to the element indicated by a red flashing LED.
• Note: Once the dial has been turned to “MAINS ONLY”, it will complete a full mains heating cycle (until the thermostat opens). Turning the control back to “SOLAR ONLY” at this point will not immediately switch the unit back to solar power. It will only switch back again after the mains heating cycle is completed (i.e. the thermostat opens) and the thermostat then closes again. You can finish the mains heating cycle faster by reducing the thermostat temperature setting until the thermostat opens. Test solar power first.
• Fast flashing red / green LEDs indicate a short between a PV (photovoltaic) lead and earth OR a partial short of the element to earth. Wait at least 20 seconds after any disconnection or other correction step for the LEDs to stop flashing.
• If you are having DC power supply issues, check if the DC circuit breaker or isolator is faulty by measuring the voltage across the DC circuit breaker or isolator whilst DC power is being supplied to the element. If there is a voltage drop across the disconnect switch, it is faulty and needs to be replaced. Also check all DC fuses if installed.

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

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.

kW_p or W_p 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%. ↑