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flokstra avatar image
flokstra asked

Lithium superpack 100ah discharge

Hi there!

Been searching the forum for an answer, but no luck so far.

I've got a setup with a Lithium Superpack 12v 100Ah, mppt solar, orion-tr smart, multiplus 1200 and a bmv-712. Everything functioned fine over the last two months. I've put away the van for a few days now. When i came back, the bmv was sounding the alarm and reads only 9,8V. All dc loads are disengaged or turned off. Only the bmv is connected.

How can the voltage drop that low? As I understood the internal bms of the superpack should've disconnected the load long before reaching 9,8V! And on top of that, the bmv is the only (tiny) load connected. How is this possible?

All help is very much appreciated!

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BMSSuperPack
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2 Answers
Alexandra avatar image
Alexandra answered ·

@flokstra

Don't know if this is the case for you as I have never used a victron superpack. but I did have some lihtiums go into a low power mode in storage, also reading 9.8V had to use the bms wake up procedure in the manual for the product. So the batteries were charged the bms had shut down due to inactivity.

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flokstra avatar image flokstra commented ·

Hi @Alexandra !
Thank you for your answer. I searched around this storage mode a bit, but didn't find anything. It's supposed to shut off at 10V, and then After sind me time of storage i can understand the bms taking it down to 9,8. But within a few days is crazy. And it also didn't even shut down yet as the bmv was still up. I'll take the multimeter to the superpack tomorrow and check if there's any voltage difference between what the bmv reads and what's actually there.

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Alexandra avatar image Alexandra ♦ flokstra commented ·

Hi @flokstra

There is also a possibility that one cell drew down lower then it should. It happens with small power draws. Alot of bms are not sensitive enough to pick it up and protect against it.

I am only guessing as i do not know what SOC you left it at. But you are right in a few days at most 1 or 2 AH is drawn so not enough to make it discharge much. Was everything except the bms removed, including wiring all other wiring for loads or just the loads. The other possibility is the wiring has been draining it somehow.

I guess you will only see when you get there.

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Paul B avatar image
Paul B answered ·

WAS it full in the first place it was it at 14.2 volts when on charge - before you disconnected it. or were you looking at the SOC and seeing 100% so presuming it was full . Voltage is always a better indicator of charge level

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Related Resources

Victron VE.Bus BMS product page

Victron 3rd party BMS compatibility page

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