PowerOptimal Elon® Smart thermostat specification V1.15
INTRODUCING THE
PowerOptimal Elon® Smart Thermostat
The Elon Smart Thermostat transforms standard electric geysers into smart, solar PV-ready green appliances. Android & iOS apps allow monitoring and management with your smartphone, including water temperature and grid & solar energy use. Real-time monitoring and communication deliver actionable data. Early alerts for leak detection, element failure and other geyser faults reduce cost, damage and inconvenience. Simple installation with plug- and-play solar PV enables cost savings and reduced reliability on fossil fuels, improving quality of life.
Document Version: 1.15
SPECIFICATIONS
Rated input voltage | 230V AC, 230V DC |
Rated input current | 18A AC, 15A DC |
Mains (AC) voltage range | 230V +10% -15% |
System power supply | Solar PV DC or 230V AC mains |
Power consumption | 3W on either AC or DC (solar) power |
Data retention on device | 2 weeks for high-resolution server data, 1 year for mobile app data |
Solar voltage | 30 – 230 V DC |
Thermostat | Electronic thermostat with 0.5 °C accuracy |
Safety | Electromechanical thermal cutout |
Reverse polarity protection | For solar PV connections |
Lightning protection | 8 kA |
Self-tests | Component failure, wiring failure, element failure, insulation failure, hot connection |
Enclosure ingress protection rating | IP40 |
Radiated immunity | IEC 61000-4-3 Level 3, 10 V/m |
Annual energy production compared to inverter-based system | > 90% when solar PV array and geyser element are matched correctly |
Standards conformance | SANS 60730-1, SANS 60730-2-9, SANS / EN 301 489-1, SANS / EN 301 489-17, ICASA Type Approval, LoA from NRCS |
Dimensions & weight | 23 x 12 x 11 cm, 0.3 kg. Box dimensions: 27.6 x 17.5 x 13.5 cm |
Patents | Granted: ZA2019/02129, GB2583814B, ZA2022/08516, EP 4100979, US 12,122,914, GB2618349, ZA2024/08399, EP4519612 Pending: PCT/ZA2024/050065, CN2023800381161, US 18/861,142, AU2023265634, ZA2023/11726, ZA2024/08845, PCT/ZA2025/050066 |
Registered Designs | ZA F2022/00962, F2022/00963 |
Communications link | Wi-Fi Client, Wi-Fi Hotspot (2.4 GHz) |
Measurements | AC energy, voltage, current (5%) DC energy, voltage, current (5%) Temperature: water & ambient |
Data logging | 15-second data retained for 14 days 5-minute data retained for 366 days |
Other features | Mobile app for installers and users Full installation self-check Remote firmware upgrades 50 000+ switching operations on thermostat Cloud backend for remote monitoring & alerts Estimation of water use |
Advanced features scheduled for external availability in H2 2026 | Leak detection (software-based) Anode condition monitoring |
It is important to match the solar PV array and heating elements for maximum power transfer efficiency. Refer to the table below for the recommended AC heating element power rating for different solar panel specifications and configurations.
TABLE 1. GUIDE: PV ARRAY AND GEYSER (WATER HEATER) ELEMENT MATCHING
Solar PV array size (kWp) | Best matching geyser element size (kW) | 2nd choice geyser element size* (kW) | Geyser (water tank) size (litres) |
1 – 1.6 | 4 | 3 | 100 - 200 |
1.6 – 2 | 3 | 4 or 2 | 100 - 200 |
2 – 3 | 3 | 4 | 150 – 300 |
* Second choice element size would reduce efficiency by 10 – 20%.
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 < 15A Voc < 230V Power < 3 kWp
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.