Although this FAQ is for the Powerwall, this applies to any good single-phase battery.
The Powerwall 2 can be installed on one phase of your 3 phase supply as long as you don't want 'whole house' backup.
There are 3 things you need to ensure:
1. The Tesla Gateway monitoring system has a Current Transformer (CT) on all 3 consumption phases.
2. The Powerwall is configured to discharge enough power on the battery phase to make up for the other 2 phases' consumption. i.e. it adds together all the phases (this is the default behaviour).
Then your 3-phase meter simply nets out the consumption.
You get all the self-consumption benefits as if the battery were on all 3 phases - as explained here:
How does a single-phase inverter on a 3 phase supply affect my self-consumption?
3. Any loads you want to be backed up need to be on the same phase as the Powerwall.
Comments
2 comments
Is there an issue with charging a PW2 with 3 Phase from PV?
I have 3 Phase power and I'm not sure if I should get a Single or 3 Phase inverter with my PW2
I've read that if I get a 3 Phase Inverter then the Powerwall 2 will only charge from 1 phase and the PV from the other 2 phases will be lost to the grid
I understand the PW2 will only provide backup to the Single Phase but are there limitations on the charging side?
The PW2 can only be coupled into one AC phase. So - if you have a 3 phase inverter the PW2 can only be physically connected to one of the output phases of the 3 phase inverter.
But - this should not be an issue in regular use because of the way 3 phase net metering works.
Say you are generating 6kW of solar across all 3 phases (2kW per phase) and the PW2 is connected to only one phase. The Powerwall can still charge at 6kW without any imported electricity being billed. 2kW of the charging power will come from the solar directly. The other 4kW will be imported from the grid on the PW2's phase, but will be immediately offset in the 3 phase net-meter by the 4kW of solar being exported on the other 2 phases. So you won't be billed for any grid energy.
Where a 3 phase solar inverter is a disadvantage with a PW2 is when you want to operate off grid. The 3 phase solar inverter can't fire up the solar without seeing 230V on all 3 phases. The PW2 cannot provide this on all 3 phases when the grid is down, so you won't be able to charge from the solar at all without the grid.
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