Lime scooter battery balanced early

Ghz24

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Apr 9, 2022
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I just acquired a couple of 10s3p lime scooter bateries.
They were a real good deal but they had been in storage for a bit. When I got them the individual sets were 0.25 volts out of balance running from 3 to 2.75.
I plugged it into a cheap bulk charger to see if the bms would wake up, figuring it would take a long time to finish balancing.
A few hours later I had to leave so I disconnected the charger and put a meter to it to see how it was going.
The cell sets were perfectly balanced but at 3.98v not 4.2.
I was wondering if lime built the bms to balance first realizing the juicers wouldn't ever leave the battery on the charger long enough to top balance the cells.
Anyone else seen this happen?
 
Is it a resistive shunt balancing BMS, or is it a capacitive charge-shuffling type?

The former typically has a bunch of identical small parts (transistors, resistors, etc) on each "channel". The latter may only have a single big chip, or a few smaller identical ones, but not one per channel.

If it's the latter, it could be balancing the entire time it is charging, and if the charge pumps are good enough they could fix a fair imbalance relatively quickly. (though cost likely means they wouldn't be).


It could also be that the cells are all just of the right properties that make it balanced well near the top, but possibly far out at the bottom.
 
I've also bought surplus scooter packs, and sometimes a few groups will be sitting as low as 2.5V-2.7V when the majority were at 3V. It seems to me the cells charge really fast when they're low like that, like they'll make up a 1/2 volt in less than a minute and catch up to the rest.
 
Well, it's quite old, isn't it? I had some in the streets, and the first under water in Paris.
There's a special tiny BMS, and I found everything ok.Not really 10 cables, maybe only 9, that's only that I noticed.
No so good with 13S3P, (Samsung 21700), impossible to charge correctely.
 
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