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Willem Louw avatar image
Willem Louw asked

Multiplus II not charging battery if BMS CAN connected

Hi Everyone

I recently installed the following system:

  • Multiplus II 48/500/70
  • Cerbo GX
  • ET112 Energy meter
  • Greenrich UP5000 5kWh LiFePo4 battery (reports as a Pylontech, so either a clone or a rebrand)
    1674231574543.png


The purpose of the system is to act as an UPS for the time being and later be upgraded to a solar system.

The problem: The battery does not charge from the grid when the CAN comms are connected. Disconnecting the comms starts the battery charging, but the Multiplus reports "Battery Low Voltage" faults, even when at >70% SoC.

I've configured a ESS Assistant to "Keep Batteries Charged", but no dice.

Could anybody maybe spot my error, please?

1674232240201.png


Thanks in advance.

battery charging
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1674232240201.png (92.7 KiB)
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Willem Louw avatar image Willem Louw commented ·

Thanks @Matthias Lange - DE

In desperation I did try implement the workaround provided by Thomas Raabo in the link you provided, but alas I see no change.

1674241489628.png

So, I reverted it back.
Should I rather then just unplug the CAN from the BMS? (make it a "Dumb" battery)

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1 Answer
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

Pylontech is 15S your battery is 16S.

The GX device loads some kind of 15S protocol if a "Pylontech" is detected and with that it doesn't charge above 52V.

https://community.victronenergy.com/questions/178050/very-slow-charging-ess-2-multiplus-2.html?childToView=178155#answer-178155

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