question

blip15 avatar image
blip15 asked

Stacked Multiplus II Humming on ESS/Pylontech and then overload

I have three Multiplus II 5000 inverters stacking in a single phase senario, linked to a Cerbo GX, powered by 20 Pylontech Us3000 batteries and an LV Hub.

When the Batteries are set to charge the system works correctly.
When the system is disconnected to the grid, the system works correctly.
When the Grid is active, the battery SOC is above the ESS SOC, the three inverters hum in a half second duty cycle. It seems like the inverters are fighting each other. The battery begins charging and after a few minutes begins discharging but a lot slower than expected, and the ESS reaction time is much slower than expected.

All DC Cables are the Same Lengths, All AC Cables are the Same Lengths, The Comms Cables are isolated from AC and DC so no interference. The Cerbo GX reads the Pylontech batteries perfectly.

After leaving the system in this state for a while an overload warning comes up a few times before an overload fault and the inverter system switched off.

What could be causing this?

cerbo gxESSPylontechfault
2 |3000

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1 Answer
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

Hi @Blip15,

What you are describing sounds like an issue with the Loss of Mains (LOM) detection system.

Please read this:

https://www.victronenergy.com/live/ve.bus:grid-codes-and-loss-of-mains-detection

And also read through some of these other cases - ESS, LOM and Overload.

2 |3000

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