Smart Solar Surplus Control for Electric Water Heaters | IAMMETER
Maximize Solar Surplus with IAMMETER: Use WPC3700 + WEM3050T to Power Your Electric Water Heater Smartly
As residential solar PV systems become more popular, maximizing solar surplus (PV surplus) usage has become a top priority for many homeowners. IAMMETER offers a smart and efficient solution that combines the WEM3050T 3-phase Wi-Fi energy meter and the WPC3700 adjustable power controller to intelligently divert surplus solar power to resistive loads like electric water heaters. This not only increases self-consumption but also improves the overall return on your solar investment.
What Is Solar Surplus (PV Surplus)?
When your solar PV system generates more electricity than your household currently consumes, the excess energy is usually exported to the grid. This extra energy is called "solar surplus" or "PV surplus". Since the grid feed-in tariff is often lower than the purchase price of electricity, using surplus solar energy directly within your home is more cost-effective.
System Architecture and Working Principle
1. WEM3050T: Real-Time Monitoring of Solar Generation and Grid Flow
The WEM3050T is a powerful three-phase Wi-Fi energy meter from IAMMETER that provides accurate real-time data on:
- Solar power generation;
- Household power consumption;
- Exported or imported power to/from the grid.
2. WPC3700: Smart Power Control of the Electric Water Heater
The WPC3700 is a Wi-Fi adjustable power controller designed for resistive loads such as electric water heaters. It supports 0–100% continuous power output adjustment and can be controlled via:
- IAMMETER Cloud API,
- MQTT,
- Local automation platforms like Home Assistant.
3. Cloud-Based or Local Automation Logic
The system works by:
- Continuously monitoring solar surplus using WEM3050T;
- Calculating the available excess power;
- Dynamically adjusting the WPC3700 output to match the surplus;
- Ensuring the electric water heater absorbs the excess solar energy instead of exporting it.
The logic can run either on IAMMETER Cloud or be fully integrated into a local smart home platform like Home Assistant.
Key Benefits and Energy-Saving Effects
| Advantage | Description |
|---|---|
| Maximize solar self-consumption | Use your solar power directly instead of sending it to the grid |
| Reduce grid export | Automatically absorb surplus solar into high-power devices like heaters |
| Save on electricity bills | Especially effective in regions with time-of-use pricing |
| Automation-friendly | No manual switching needed – completely automated based on real-time data |
| Platform compatibility | Supports IAMMETER Cloud, MQTT, API, and Home Assistant |
Typical Applications
- Solar-powered water heating systems
- Electric space heaters
- Other high-power resistive loads
(Note: Not suitable for inductive loads such as motors.)
Expand Capabilities with Home Assistant Integration
For users seeking local, private, and customizable automation, IAMMETER offers native integration with Home Assistant. With this setup, users can:
- Monitor PV surplus in real-time;
- Automatically control WPC3700 output;
- Link with other devices and sensors;
- Visualize energy flow and consumption.
This makes it easy to build a DIY solar energy management system tailored to your needs.
Conclusion: An Intelligent Solar Surplus Control Solution by IAMMETER
If you already have a home solar PV system and want to better utilize the daytime solar surplus to heat water or power other high-consumption devices, IAMMETER’s solar surplus control solution is an affordable and scalable option.
By integrating the WEM3050T energy meter and WPC3700 power controller, you can:
- Divert excess solar energy to useful loads;
- Increase the self-use ratio of your solar system;
- Lower your utility bills and boost your return on investment.
👉 Learn more: Solar Water Heater Control Using PV Surplus
