SAJ HEMS
Use Zerofy as your SAJ HEMS. Monitor solar production, optimize self-consumption, and automatically control EV chargers, heat pumps, and smart plugs.
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SAJ HEMS: TL;DR
Zerofy transforms your SAJ PV system into a complete Home Energy Management System (HEMS). Monitor production, optimize self-consumption, and control your connected devices – all from one app. No additional hardware required.
About SAJ
SAJ (Guangzhou Sanjing Electric) is an inverter maker from Guangzhou, China. Homes usually have the H2 hybrid inverter with B2 battery or the HS2, HS3 or AS2 all-in-one storage systems; the eManager unit and the Caro wallbox tie them together. Its monitoring app is Elekeeper.
What is a Home Energy Management System?
A HEMS (Home Energy Management System) helps you get the most out of your solar installation. It monitors your PV production in real-time and automatically steers connected devices like EV chargers, heat pumps, and smart plugs to maximize self-consumption.
With Zerofy as your SAJ HEMS, you can:
- Monitor real-time solar production and home consumption
- Optimize self-consumption through intelligent device control
- Save on electricity bills with dynamic tariff integration
- Track your energy independence and CO₂ savings
Key Features
Real-time Monitoring
See live data from your SAJ inverter: current production, consumption, grid feed-in, and battery status.
Smart Autopilot
Automatically control EV charging, heat pumps, and appliances based on solar surplus.
Dynamic Tariffs
Integrate electricity spot prices (Tibber, aWATTar, etc.) to optimize for cost savings.
What SAJ offers on its own
Before connecting SAJ to Zerofy, it helps to know what SAJ offers on its own:
- EV charging: SAJ’s Caro wallbox (7 kW, 6–32 A, or 11 kW, 6–16 A) can charge from solar and supports OCPP 1.6J. The manual says PV charging needs an SAJ H2+B2, HS2, AS2 or HS3 storage system plus the eManager.
- Heating: The SAJ eManager has two dry-contact (DO) outputs for a heat pump, switched by tasks you set up in the app. SAJ says Elekeeper supports heat pumps and water heaters but doesn’t list compatible models.
- Other loads: SAJ says Elekeeper can also connect smart sockets but doesn’t name the supported models.
How It Works
- Connect your SAJ system – Zerofy reads your plant from the SAJ cloud: you add Zerofy as a developer in the Elekeeper app and then enter your Plant ID in Zerofy.
- Add your devices – Connect your EV, charger, heat pump, or smart plugs
- Enable Autopilot – Let Zerofy automatically optimize for solar self-consumption
- Track your savings – Monitor your energy independence and cost savings
Good to know: How fresh the data is depends on how often the SAJ cloud updates. For the battery, Zerofy supports forced charging but not switching the battery mode.
Why Choose Zerofy for SAJ HEMS?
| Zerofy HEMS | Hardware-based HEMS | |
|---|---|---|
| Hardware cost | None | €500-1000+ |
| Installation | App download, 5 minutes | Professional electrician |
| Monthly cost | Free or €7/month (Plus) | Varies |
| Device support | 60+ brands | Limited selection |
| Updates | Automatic, free | Manual/paid |
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