If I give a BMS slightly lower volts, will it still balance?

[marka-ee]

I have a new kaabo scooter that seems to want to charge to 4.2 volts per cell, something I really don't like at all, as I value cell life over maximum capacity.

My question is: I see some charger being sold that supposedly charge to 90% or 80% by switch , for these types of scooters. Can you really feed a BMS a slightly lower voltage and still expect it to do it's balance function ? It's probably a generic type 48 volt BMS, built into pack.

 

[marka-ee]

Thanks for the detailed answer. On my bike I have been charging to 4.1V per cell, and only rarely discharge to 3.4 V per cell, with no BMS at all. It's been ok for 3 years now. But these are higher quality cells.
For the scooter, what if I do similar to your suggestion and charge to a voltage of about 4.1 by pulling the charger early and once in a while let it do a full charge to allow the bms to balance the battery? Maybe a good compromise?
Hacking a programmable bms into the pack would be ideal but would invalidate the 1 year warranty.

 

[marka-ee]

On the bike, which is 36 volt (10s) I charge with an rc charger but bulk charge. Now and then I check the cell to cell voltages, and they are remarkably close. But my main concern is the scooter, which is new. If I pull the charger off when it hits 4.1 x 13 volts but once every 10th charge I let it do it's full 4.2V balancing would that be sufficient?
Yes, batteries are a consumable, but non-toy EV's like cars absolutely do not charge to 100%. They have warranty claims and reputations to uphold a bit more than smallish china scooter companies who have to rely on off the shelf china bms's and packs. Virtually no engineering department or English user manual translators My old scooter, a m365, did only charge to 4.1 and has a bms that communicates to the motor controller as well as an app or i2c bus to let you read out cell voltages. Anyways, full charge every 10th a good strategy?

 

[john61ct]

If you want good longevity and proper balancing

buy an active balancer that will do the job in a short time (at a decent current rate) and at any SoC/voltage point you desire.