2 phase power with PV and battery storage.

[sbm74]

We've had to install a second single phase in order to be able to run  2x ASHP and 2x EVCP. We're also installing a 4kW PV array and are considering battery storage. We're getting a lot of conflicting advice about how this  would work in practice. Am I correct to assume that I'd need a separate inverter and battery for each phase or is there a way of being able to use one battery across both phases? 

 

Thanks for the advice as ever. Also posting this in the PV forum.

[JohnMo]

4 minutes ago, sbm74 said:

run  2x ASHP and 2x EVCP

Obvious question - why?

 

Do really mean 2 phase or just two meters so you can have 200A available? So 44kW

[sbm74]

Yes, UKPN have provided 2 single phase supplies.  2 ASHP as it's a big house and the demand is greater than one heat pump can provide. 

[sharpener]

Presumably UKPN have put in two cables, supply heads and meters. In which case there is no way you can have any equipment which is connected to both supplies at once. So you are a bit stuck as to what you can do. Maybe have the HPs on one supply and the PV/batteries/EV on the other, then you could have different tariffs which are optimised for each use pattern.

[Dillsue]

On 09/11/2023 at 19:16, sbm74 said:

Yes, UKPN have provided 2 single phase supplies.

Do you know if this is 2 supplies off differing phases with 400 volts between them, or 2 supplies off the same phase with 0 volts between them?

 

With a 4kwp array/battery you'll do well to power 1 ASHP and 1 EVC so a single inverter/battery on one supply would likely use everything the array can provide for most of the time.

 

If you want to charge the battery(s) on a TOU tariff you could have a single battery and a pair of contractors switching the battery between the 2 supplies as required or a battery on each supply.

 

If you've got 2 differing phases coming into the house you may get a 3 phase inverter to run on 2 phases but youd need to speak to the manufacturer to confirm