Installing a Solar PV & Battery Storage System to a 3-Phase Home.

Electricity is supplied to homes and business across the country in either single phase or three phase supply. Most homes are supplied with single phase electricity but larger homes or homes with a higher demand may have a three phase supply. This could also be for powering an air source heat pump or another high demand item such as an elevator.

If your home is supplied with three phase the electrician who installed your electrical system would have designed it so that the phases are balanced. This will mean that your power sockets, lighting and kitchen appliances are spread out evenly across the 3 phases.

When we come to design a solar PV system we must also consider this and install a suitable 3phase inverter which will send solar generated power to all 3 phases so that you can use this power where ever it is required in the home.

This is where the correct design for a solar panel and battery storage system becomes essential. A solar PV system on its own will generate and distribute power evenly to all three phases but if you are not using power in your home evenly across all three phase then the system can become inefficient.

At Solarbility we can supply 3 phase hybrid inverter and battery storage systems that will work for your 3 phase home. Any power that is generated by your solar panels will be distributed across the phases but only when and where it is required, any surplus power will be stored in the battery for later use.

For example: Your solar panels are generating 3kW of live power, your home is using 3kW of power but mostly in the kitchen which is on phase 2. Our intelligent battery storage system will detect this and deliver the 3kW that is required to phase 2 to support that demand.

Other things to consider with 3 phase supplies: A few years back a customer asked us to install an electric car charging point for them and instructed us that their single phase supply had been upgraded to three phase at a cost of a couple of thousand pounds.

The ambition was to charge his electric car at a faster rate, 3 times faster than with single phase but this turned out not to be the case. Although a 3ph EV charge point can technically charge at 3 times the rate of a 1ph charger, it is the electric vehicle itself that determines what rate it can receive the charge from an AC power source.

Electric cars can be charged at fast charging stations at ultra fast speeds but this charging is done with DC electricity. The vehicle’s lithium ion battery is charged and stores DC electricity, in order to charge from an AC power source the car has an on board inverter to convert the AC power to DC for the battery. It is the size of this inverter that determines the rate of charge, and most are rated at 11kW per hour, just slightly more than a single phase charge point which is 7kW.