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tilo avatar image
tilo asked

Multiplus-II with grid injection - how to avoid injection in case of generator backup?

Planned: Multiplus-II + MPPT + Venus GX in ESS mode with grid feed-in. The house has a backup generator in case the grid fails which can be started manually, switching also manually from the grid to the generator.

Once the house is connected to the generator, can it be avoided that the Multiplus-II injects towards the generator?

I have not found an assistant or any other means to disable grid injection (towards the generator) and disable LOM (Loss Of Mains) detection based for example on a signal to AUX1 input. The signal can come from the same switch that selects grid or generator (with an additional circuit).

Is there a way to make this work with Victron-gear only? Of course without having to modify the ESS/Multiplus-II configuration manually before and after using the generator.

Can an external control (Raspberry) disable grid feed-in when the generator is connected?

Can the LOM detection be changed/disabled by an external control?

Or better bypass the Multiplus-II when the generator runs (and not charge batteries)?

A Quattro is not an option because of grid feed-in regulations.



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2 Answers
Paul B avatar image
Paul B answered ·

Hi Lilo

you could install two relays to isolate the MPII and connect the Gen to the house

if you put a cut off contactor on the generator and the AC1 out line and used the small NC/NO contacts on the contactors

you could isolate the MP2 and connect the Gen direct to the loads automatically with just the start of the generator. plus you do away with the change over switch and also no feedback to the gen being posable. as per your option #3

ie you start the generator and the gen contactor closes and thus opens the N/C switch on that contactor that would then turn off the contactor coil connecting the MP2 to the loads. and when the Gen stoped the loads would be reconected to the MP2.

down side you may get a change over pulse to the loads.

dont know if this is of any help but it should work ???

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tilo avatar image tilo commented ·

Thank you for the detailed answer.

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hochgattererjohann avatar image
hochgattererjohann answered ·

I plan to build nearly the same configuation but with 3 Multiplus II (to have 3-phase output).

I have an 1-phase generator.

Is it possible to connect this 1 phase to the Input of the 3 Multiplus II and get on the OUT side 3-phase to run a heat pump.

Thank you for an answer



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