question

martghh avatar image

unexpected Inverter shutdown

Hi,

after running several months with no issue at all, the MP II swicthed off and no message appeared on the GX not the VRM alarm log. Later i discovered irregular behaiviour of the SOC coming from the BYD BMS (a call to EFT is already opened) - nevertheless, i would expect some sort of logging from the MultiPlus II about that - any other location/source i could look at ? The only change within the last 2 weeks was updating the GX to 2.60.

best regards,

Martin

Multiplus-IIBYD
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@martghh

Is this still an issue?

The BYD may not have reported an issue to the gx at all. Is there a way to interface with the BYD at all maybe find out if there was a weak cell and the battery shut down?

The other thing to check is if the multi's own battery monitor is checked and configured. I have had systems when the multi has noticed an issue on ve bus voltage but the batteries say nothing yet have a weak cell and shut it off obviously dropping the voltage of the system and causing a shutdown.

martghh avatar image martghh Alexandra ·

Hi Alexandra,


meanwhile one of the two batteries have been detected as bad, it takes more than 5 days to get the technical support responding and few more days to finally come to the conclusion that one is out of order. Since then (nearly 2 weeks ago) i wait for the replacement to arrive. Regarding the symptoms, interesting was that the BMU reports a SOC between 0% and 100% (jumping back and forth) which finally leads the MultiPlus to shut down immediatly, what i still do not fully understand.

best regards,

Martin

Well you are on the way to fixing your system so that is good. Sorry it has taken so long.

The are possibly some faulty circuit boards or connections inside the batteries that are 'switching off' and so contact is lost with the cells and the bmu can shut down for safety reasons. It happens across quite a few lithium based battery brands from what I have seen. Not convinient at all though.

Does the battery voltage fluctuate as well? On some batteries you can run the lithiums as 'dumb' untill the computer part is sorted out, using the settings on the multi with it's internal monitor.

Just check in the battery manual if it is allowed. Some manufacturers will void the warranty.

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