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pedaaa asked

Feature Idea: Multiplus II ESS -> use AC-Out 2 as Generator Input?

I just came across this idea. And it should be possible with just a Software change.


Usually the AC-Out 2 is dropped of, if grid fails.

But why not do it the other way round and use it as a Generator Input?!


-> connect a Generator to AC-Out 2

-> install a EM24 meter between Generator and AC-Out 2, so that Victron knows about it

-> if Grid is available on AC-in, AC-Out 2 must be disconnected

-> if Grid fails, AC-in is disconnected, and AC-Out 2 should be connected

-> Generator start/stop signal should start the Genset

-> if Grid comes back again, Generator must be stopped and AC-Out 2 disconneced

-> then reconnect Grid


this would be a perfect feature to be able to use the Multis in an ESS with a generator as an backup system. Also it would solve the issue having Generator Connection issues because of Grid Codes.


There are other Chinese Manufaturers that exactly support this scenario.

(e.g. Deye SUN Hybrid)

I see no reason, why Victron woulnd´t also be able to do that also?!


Generatorac out 2
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wald avatar image wald commented ·
Do you think is possible to use AC output 2 as AC input 2 for generator ?
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Kevin Windrem avatar image Kevin Windrem wald commented ·
See my post from Dec 2022. No, it is not possible.
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Kevin Windrem answered ·

Great idea but not just software unfortunately. In order for the Muti to use an AC source, it must synchronize it's inverter/charger core with the incoming AC (voltage, frequency and phase) BEFORE closing the AC input relay. The necessary circuitry to monitor the generator and sync to it is not present on the AC 2 output. A grid meter doesn't provide the phase information necessary to synchronize with the AC.

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pedaaa avatar image pedaaa commented ·

I am not talking about any synchronizing. Why would you need that?

Its not necessary.

No need for Generator and Grid to work at the same time:


The AC-Out 2 MUST NOT be connected if AC-in is connected for this application!

Grid and AC-In must be disconnected BEFORE AC-Out2 with the generator could ever be active.

Also the other way round:

AC-Out2 and generator must be disconnected in any case BEFORE AC-in or Grid can be connected again.


By using this logic it should work, isn´t it?

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pedaaa avatar image pedaaa pedaaa commented ·

or do you mean the internal Charger/Inverter itself would needs to synchronize with the Generator, so it wont work because of that... ?!

Ahh, too bad.

So its only able to sense that from AC-In?!

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Kevin Windrem avatar image Kevin Windrem pedaaa commented ·
Yes and yes.
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Related Resources

Additional resources still need to be added for this topic

MultiPlus Generator FAQ

GX - Generator auto start/stop

Automatic Generator start/stop

 Hybrid Generators

Virtual switch - Generator start/stop

Additional resources still need to be added for this topic