Can I use a 58.8v charger on a 13S pack

Hello,

My home built pack is 13S3P using ncr-b cells and a bms off ebay. I can't get my cells past 4.09v.

I am wondering if this could be a function of the bms?

I have two separate chargers - one at home and one at work - so don't think the charger is the issue.

Separate but related, I am wondering can I use a 58.8v charger if I keep an eye on things - even if it has to be down at each individual series?

Mario

Best to check your chargers outputs first with a multimeter, or monitor the voltage during charging to see why your not getting a full charge.

Voltage on charger should be the 54.6v expected. As I said, I have two different chargers - they are two different visual models as well.

I had the pack open and was watching. Most cells were at 4.14 while charging, but one was topped out at 4.19. After the charger turned green, and I unplugged all series settled to 4.09.

Mario

Sounds like you are disconnecting the charger too soon. If one series is high it shuts off the BMS and the charger. Have you tried letting the charger on longer and watching if the high cells discharge and the bms turns the charger on again? Other option is to drain the high series down to the lower voltage of the others. Then you plug the charger in and watch the voltages. If the same series tops out first, you might have a bad cell in that series.

Yes you could use a higher voltage charger but the BMS should shut it down the same way as the other. If the BMS doesn't shut off the charger the cells will over charge and possibly destroy them. A good BMS will stop the charger but a weak/bad BMJS will not!

Dan

Thanks Dan.

I will try those options tonight with the battery opened up.

I have some 58.8v chargers to charge up 52v batteries...

If you don't keep an eye on things.



It might be possible to tune the charger down to 54.6v, and then you have a proper 13s charger. Look for a pot with a tiny screw, very close to where the DC wire comes out of the board on the charger. (inside it)

Re the 4.9v, if the cells suck, that is full for them. They do charge to 4.2v, then immediately lose some voltage instantly when the charger is removed. If you wan to make your battery catch fire, try overcharging it to force the pack into balance. Seriously, DONT go past 55v on that thing!!!! 4.3v on any of those cells and they are fire starters.

if it takes a half hour to lose that .1v, then its the bms balancing a very out of balance pack.