27.12 kWh home battery with backup power, single-phase

Three battery modules of 9.04 kWh, a Sigen Energy Controller of 6 kW, the Power Sensor and the Sigen Energy Gateway HomePro SP. Together 27.12 kWh of storage with backup power.

This is the size where backup power stops being a nice extra and becomes a real reason. An average Dutch household uses roughly 7 to 8 kWh a day of base load. With 27 kWh and a bit of sun on the roof, you get days ahead without the grid.

Where the limit lies

The controller delivers 6 kW continuous. That doesn't change if you add more modules, because the limit sits in the inverter, not the battery. What you gain with a third module is runtime, not power. If you want more power during an outage, you need a heavier controller, and that's a different package.

An honest note

At 27 kWh on one phase you run into something few people realise beforehand: charging also happens at only 6 kW. From empty, a full charge takes just over four and a half hours at full power, and in winter you'll rarely get that power from your panels. For anyone charging cheaply overnight on a dynamic contract, that's fine. For anyone who wants to fully cycle the battery every day on solar power alone, three modules is on the generous side.

The gateway

The HomePro SP can switch 12 kW and works with full or partial backup power. It weighs 25 kg, is IP54 rated and hangs on the wall. Without this box, nothing switches over during an outage, however big your battery is.

Installation

Budget 500 euros on top of the normal installation package for fitting the backup power circuits.