question

Eran Rundstein avatar image
Eran Rundstein asked

Multiplus continues to charge even if disconnected from Cerbo GX

Hello everyone!

I have a REC BMS Q connected to my Cerbo GX, which is also connected to a Multiplus 3000. I have enabled DVCC/SVS/STS like the REC BMS manual suggests and I am running an unexpected problem: when I disconnect the BMS from the Cerbo, or when I disconnect the Multiplus from the Cerbo, the Multiplus continues charging.

I would've expected that if there is loss of communication the Multiplus will abort charging. Going over an Orion BMS manual, which is also Victron-CAN compatible, they do indicate that loss of communication should prevent the Multiplus from turning on.

The Cerbo GX manual also indicates that should be the case - in the section where they describe what happens if you power up the CerboGX from the Multiplus AC ouput. But in my setup for whatever reason if I power up the Multiplus with the Cerbo turned off, it is still happy to charge - which is unacceptable for safety reasons...

Does anyone have any idea what I am missing?

I'm attaching some photos of the information displayed on the Cerbo.

Thank you!


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MultiPlus Quattro Inverter Chargercerbo gxmultiplus ve.bus
img-1752-copy.jpg (1.5 MiB)
img-1753-copy.jpg (1.5 MiB)
img-1755-copy.jpg (1.5 MiB)
img-1756-copy.jpg (1.5 MiB)
img-1757-copy.jpg (1.3 MiB)
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1 Answer
mvader (Victron Energy) avatar image
mvader (Victron Energy) answered ·

Its like that indeed. Not perfect, but is what it is. For best safety, make the BMS control a relay.

I can’t remember where, but a long time ago I wrote the same, but then more verbose, and end conclusion: for a safe system with 3rd party battery, have the safety features (relay) built into the battery/bms and controlled by the battery/bms.

Just like all the professionals do: BYD, Pylon, Battleborn, Freedomwon, and so forth.

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Eran Rundstein avatar image Eran Rundstein commented ·
Thank you. The BMS does have a relay, but I was hoping for a more elegant solution given all these fancy buses. Oh well :/
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