My VictronMultiPlus-II 48/5000/70 occasionally trips my BMS (Overcurrent) under light load.

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tony-from-west-oz asked Sep 13, '23

My VictronMultiPlus-II 48/5000/70 occasionally trips my BMS (Overcurrent) under light load.

I have a problem with my Victron inverter. Occasionally, at low load (overnight usually) it trips off the BMS due to "Overcurrent". The BMS shows a current of 352.2A.The 100A Battery fuses are not affected, The FETs in the BMS are faster than the battery HRC fuses.

When reset, the BMS has a charge delay to prevent excessive inrush current into loads, but after this delay, the BMS may trip on "Overcurrent" again. After a while, the inverter will start normally with no problems from the BMS protection system when reset.

I was advised that some Victron inverters had a similar issue which was a common issue for that production batch..
How can I check if my inverter is part of that batch, so I can get it repaired/replaced?

Thanks in advance.

fault

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Answer 1 · 2023-09-14T02:19:03Z

tony-from-west-oz answered · Sep 14, 2023 at 02:19 AM

Just to aid investigation,here is a photo of the ID sticker on the inverter.

20230914-1007571.jpg (2.5 MiB)

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Answer 2 · 2023-09-14T02:45:35Z

snoobler answered · Sep 14, 2023 at 02:45 AM

Do you have anything with high surge like a well pump?

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tony-from-west-oz commented · Sep 17, 2023 at 01:57 PM

No high surge loads. No heavy loads when it trips off. Usually in the early morning 3-5am. I wake up because my CPAP machine stops working.

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Answer 3 · 2023-10-18T14:05:43Z

tony-from-west-oz answered · Oct 18, 2023 at 02:05 PM

After getting help from a local Perth member, I now have the generator able to connect and carry the load / recharge the battery.

It is interesting to note that the BMS over current trip has not occurred since this intervention.
No changes were made to the 48V system or the inverter, other than limiting the generator current to the inverter, then relaxing it to allow the full generator output ( 7.5KVA) to be used by the inverter/charger.

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