Bms Bestway 20s 30A 72V pack

[marce002]

Hi

i fixed a 72v 30a pack made of 240 inr 26E 2600mah 12x20 array.pack.... where an entire row of 12 cells were at 0v and remaining cells were fine at 4.09v...output was not present due to bad cells ... replaced all 12 with new ones but i forgot to charge all 12 leaving them at 3.7v each.... mounted and ckosed the case and tested volt an were at 81v and tested in scooter amd motor spins... so far so good 81v total...

my Q is will a full charge balance the pack? will the bms take cate of new cells imbalance? or will need to dismantle the thing and charge the cell separatedly....or maybe empty the pack to 70% or similar doing some kms 20 for eg then fully charge...View attachment 368650 sorry to ask bms behaviour...tks

 

[docw009]

I believe a good balance BMS will correct that kind of imbalance, but balance chargibg is slow. If you are in a hurry, it would be faster to charge the one group by itself up to the level of the others. You can do that if you have a suitable 4.2V lithium charger and can be done w/o disconnecting the cells. Might want to pull off the balance connector.

My guess is it would take a BMS at least a few days to balance a 20P that's off 1/2 volt on one group.,

 

[marce002]

thanks doc ... i will wait some days and use it normally... because i do not want to reopen package case and imax charge that 12cell which for sure would be the best option.hope this BESTWAY 20S bms can handle the balance...i dont have any info regarding if someone has documentation of this please share.