Connecting a plug-in battery: 800 watts, own circuit, P1 meter

The 800-watt limit

Plug-in batteries are limited to a power of 800 watts, NOS reports. If you want more power, you have to put the battery on its own circuit. Some batteries can deliver much more: Anker gives 3,500 watts for the Max AC. That power is meant for a circuit of its own, not for a socket shared with other appliances.

Why a circuit of its own

A circuit in the fuse box is protected by a fuse. Normally all power on that circuit comes from the grid, and the fuse trips when too much flows. With a plug-in battery, power can reach the same circuit from two sides: from the grid and from the battery. Milieu Centraal warns that the wiring can then get too hot without the fuse tripping, especially if a washing machine or dryer is on the same circuit. That is why Milieu Centraal does not yet recommend plug-in batteries.

Installers connect home batteries to a separate circuit in the fuse box, following the Dutch standard NEN 1010. The fire service also advises a separate circuit for a plug-in battery where possible, and at most one home battery per circuit. Make sure the circuit the battery is on is not overloaded.

Not sure which sockets are on which circuit? Switch one circuit off and see which sockets lose power. Have an electrician fit an extra circuit.

Connecting to the socket

• Plug the battery straight into an earthed socket, without an extension cord or power strip (fire service).
• Never connect two batteries to one socket through a power strip; the fire service named that as a concern to NOS.
• Do not put heavy appliances such as a washing machine or dryer on the same circuit.

The P1 meter

A P1 meter plugs into the P1 port of your smart meter. The battery then sees whether your home is feeding power in or drawing it. When your home feeds in, it charges; when you draw, it discharges.

Some batteries come with the meter, such as the Hoymiles HB-4020-AC incl. P1 meter and the TSUN 5 kWh. The Hoymiles HB-4020-AC without that addition in its name, the Zendure 3000mix and the Zendure SolarFlow 4000 Mix AC+ need a separate meter. Which meter works is in the battery's manual.

Where to put it

The fire service advises:

• a dry, well-ventilated room the fire service can reach easily;
• not in an escape route or under the stairs;
• a working smoke and/or carbon monoxide detector in the same room.

Milieu Centraal adds that a cupboard is not a well-ventilated place. If you want to put the battery in a shed or garage, check the manual for the temperatures the maker allows. The Consumentenbond found that many plug-in batteries worked almost as well at 5 °C as at 23 °C, but advises against a shed or garage for some models. CONOW gives IP65 for the Lyra 2500 AC and the Atlas 6000: protection against dust and rain.

Upkeep and checks

• Check the plug, the cables and the housing for damage, wear or discolouring, preferably twice a year (fire service).
• Keep the battery and the room around it clean and free of dust.
• Check now and then for software updates in the app.
• If the cables or the battery are damaged, contact the supplier.

Rented homes

You take a plug-in battery with you when you move, and the socket needs no building work. If you want a circuit of its own, you are changing the fuse box. Discuss that with your landlord first. Also check whether your P1 meter and your solar panels are yours or the landlord's.

Which battery suits your use is in the guide choosing a home battery. All models are under home batteries.