9.04 kWh home battery with backup power, 3-phase

A Sigen Energy Controller of 8 kW, one battery module of 9.04 kWh, the 3-phase Power Sensor and the Sigen Energy Gateway HomePro TP. The TP is the 3-phase gateway of 30 kW.

The difference with the single-phase version isn't in the battery but in what stays up during an outage. A single-phase gateway serves one phase. This one serves three, and in a house with three phases that's the difference between a working meter cupboard and half of one.

What you can do with it

During a grid outage this system delivers 4.6 kW continuous, limited by what the battery module can handle. The gateway can switch much more, but that only helps once there's more battery behind it. With 4.6 kW spread over three phases: fridge, freezer, heating, lighting and some small appliances.

One module is the starting point

This is deliberately the smallest setup. It can be expanded to six modules under the same controller, and every module you add later increases both the storage and the power until the controller hits its limit. Starting with one module and expanding later costs you nothing in lost investment.

Honest about the price

The 3-phase gateway costs 1,299 euros against 649 for the single-phase version. On a system of this size that's a substantial part of the bill. If you have three phases but everything that matters during an outage hangs on one circuit, consider whether you can simply put that circuit on the single-phase version. That saves 650 euros, and we'd rather say up front that it's possible than after the fact.

Installation

Fitting the backup power circuits costs 500 euros extra on top of the normal installation package.