Jan Olšaník avatar image
Jan Olšaník asked

Generator, ESS, Charging


I have a question about backing up with a power station versus ESS assistant.

In our system we have three Multiplus II 48/5000 inverters, Pylontech US 5000 battery, Cummins three phase diesel generator 22kW.

Once we connect the generator (and set the generator for AC in and set the ESS to keep the batteries charged), the inverters connect to the generator and start charging, but after a while (approx 2 minutes) one of the inverters (one phase) stops charging. Then the next inverter stops charging and eventually all inverters stop charging. They try to charge again and the same thing repeats. After several attempts, the inverters disconnect from the generator.

I tried each step according to the instructions on this page:
I set Dynamic current limiter, Power assist, weak ac, disabled UPS function, set grid code to Others with and without LOM. None of this helped.

Here's a setting that didn't work, even when there was no LOM.






I finally found out that this phenomenon does not happen and everything works properly if I remove ESS assistant from the inverters or set grid code to none. So it is obvious that it has something to do with the ESS assistant.

Strange thing is, that when I set the ESS assist, it automatically de-enables the dynamic current limiter and power assist, which are appropriate for generator operation. It seems, that ESS is not fully suitable with generators, am I right?

Since this is a power plant normally connected to the grid, we cannot remove ESS assist from the inverters. We actually need ess to control the flow of enrgy into the grid.

How do we do this so that we can back up with a generator and still have the ESS assistant in the inverters?

Thanks so much for the suggestions and advice!


Multiplus-IIbattery chargingESSGenerator
settings-general.jpg (257.5 KiB)
settings-grid.jpg (260.9 KiB)
settings-inverter.jpg (277.3 KiB)
settings-charger.jpg (270.5 KiB)
settings-ess.jpg (297.9 KiB)
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2 Answers
Jason - UK avatar image
Jason - UK answered ·

@Jan Olsanik I dont think ESS is intended for use with off-grid / generator fed systems.

ESS - Start page

An Energy Storage System (ESS) is a specific type of power system that integrates a power grid connection with a Victron Inverter/Charger, GX device and battery system. It stores solar energy into your battery during the day, for use later on when the sun stops shining.

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ejrossouw avatar image
ejrossouw answered ·

Have a look at the link for the LOM aspect as highlighted in the ESS manual.


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