iabeck avatar image
iabeck asked

Two phase system changing to 1 phase in power outage

I have a very specific system in mind. I want to replace a tri-phase 240v connection to the house because it is 3 times as expensive as single phase power and have a backup power source. But there is an issue, there is a 2 phase 9kVA appliance in the house that is used sometimes. The 9kVA appliance is in two of the phases, and the whole house is in the other. My options are to move the house into the two phases provided by the victron and let them manage the incoming single phase grid somehow (which I think is not possible), or have two victrons run the 9kVA in an off grid type bi-phase system when grid power is functional, and switch one of them or the two of them when the grid goes down to power the house which would be in another circuit.

system designmulti phase
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1 Answer
shaneyake avatar image
shaneyake answered ·

It is possible to run a bi-phase system with 1 phase grid-tied.
You only connect to ac input on one inverter L1 and you disable switch as group setting.
The L2 power will then come via the L1 inverter to the DC bus and then be generated by the L2 inverter. You would want to minimize this by having sufficient solar array and batteries to limit phase to phase conversion.

In a power outage the L1 inverter will disconnect from grid and the system will run as off-grid.

You currently can not run ESS in this config, possibly could run in Mode3 but I haven't tested it.

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iabeck avatar image iabeck commented ·

What would no ESS mean? You mentioned batteries, but I don't understand quite well de difference.

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shaneyake avatar image shaneyake iabeck commented ·

ESS allows you to use PV power and Export power to the grid.

If the default config, phase 2 will also be on battery so not really a problem there.
But Phase 1 will just pass grid through to loads and charge battery so the system won't prioritize Solar but rather Grid.

You should be able to do solar first when running in ESS mode 3 but not sure if will work.

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