Ok to repair 18650 pack with potentially mismatched cells?

[nomad85]

I have a 48v scooter battery with a dead group of cells (1s6p) rendering the scooter useless. I have a some 18650 cells of forgotten origin that all hold voltage well. I figure its worth a shot to try to use them to fix the battery? Any huge concerns if I use older potentially different capacity cells?

There is a balancing BMS in the pack, and the existing cells are 2200mah.
I was just going to scrap the pack and see about buying a replacement, but you can get a mini spot welder for ~$40 so it seems worth a shot to me..

 

[leffex]

It is not easy to do and If you do it prepare for it to be a little difficult and take more time than you estimated it to take

 

[999zip999]

A battery 48v we need more info about the kind of battery. If and a group of cells always use as good or better cells. No laptop cellsq

 

[nomad85]

A battery 48v we need more info about the kind of battery. q

It's the stock battery that came with the scooter, just a generic 18650 pack with BMS 13s6p. What additional info would you need?

If and a group of cells always use as good or better cells. No laptop cells

Say I did use laptop cells (I cant recall if these extra ones are from a power tool or laptop battery..), would that damage the remaining good cells, or just result in mediocre performance/range (still better than the next to no range I have now) I see it as a good opportunity to practice a repair and maybe I get lucky and it works for a year or 2 before needing replaced with better cells (if I can find them). But I don't want to mess up the remaining good cells in the pack.

Do you know of a good source for 2200mah 18650 cells? All the ones I can find look dubious. Would it be bad to use 2500mah or 2600mah cells, aliexpress has some LG's/Samsungs in those capacities.

 

[eMark]

It's probably as likely (as unlikely) that the (?faulty?) BMS may have caused the 1s6p group to die.

 

[999zip999]

Yes you can use a cell with more mah but not less. My go to guy is battery hookup.. yes a bleed resistor can be stuck on ?

 

[nomad85]

It's probably as likely (as unlikely) that the (?faulty?) BMS may have caused the 1s6p group to die.

Hmm good point, is there a way I could test for that (I have basic tools? I know the channel/wire the cells were connected to.
Also seems like a good reason to try the repair with the questionable cells before buying new ones.

Yes you can use a cell with more mah but not less. My go to guy is battery hookup.. yes a bleed resistor can be stuck on ?

Thanks!