Possible to use a BMS to charge individual cells?

[James340]

I was thinking of using a 13s BMS to charge 13 cells at a time.My crappy little charger is very slow

 

[neptronix]

No reason that a BMS plus a charger to feed it wouldn't work!

 

[chuyskywalker]

As long as they are all roughly the same voltage, it should be much quicker.

If they are not, then you could end up going slower. For instance, if you rigged up 13 cell spots and slapped in 12 4.0v batteries and 1 3.0v battery, the BMS is going to dramatically reduce charging amperage because most of those cells will quickly fill up and you'll be stuck with the amps the bleed resistors can handle, which is likely a lot lower than what you could charge single cell at.

Otherwise, though, a totally valid strat.

 

[BlueSwordM]

I was thinking of using a 13s BMS to charge 13 cells at a time.My crappy little charger is very slow

That will work.

Alternatively, if you want to do it quickly, you could acquire an active balancer.

 

[amberwolf]

I was thinking of using a 13s BMS to charge 13 cells at a time.My crappy little charger is very slow

Since you'd be charging a battery normally at that point, it should work if the cells are good.

The cells should equal in voltage to start with, and you must wire them all in series just like in a battery, and then connect your 13s charger (54.6v for the typical 13s pack) to the BMS charge port.

Then the BMS will manage the charging for you just like a regular batter, because it now *is* a regular battery.


If the cells are not equal in voltage, then whenever the first one reaches full the BMS will turn off charging to equalize that one down enough to let charging resume, and from that point on charging will be slow. If the votlage differences are large, it could take hours, days, to weeks, to finish the charge / balance process. Just like a regular battery.

 

[James340]

That will work.

Alternatively, if you want to do it quickly, you could acquire an active balancer.

I have a 13s active balancer.I didn't think of using it for this.

 

[James340]

Since you'd be charging a battery normally at that point, it should work if the cells are good.

The cells should equal in voltage to start with, and you must wire them all in series just like in a battery, and then connect your 13s charger (54.6v for the typical 13s pack) to the BMS charge port.

Then the BMS will manage the charging for you just like a regular batter, because it now *is* a regular battery.


If the cells are not equal in voltage, then whenever the first one reaches full the BMS will turn off charging to equalize that one down enough to let charging resume, and from that point on charging will be slow. If the votlage differences are large, it could take hours, days, to weeks, to finish the charge / balance process. Just like a regular battery.

I had not thought of in series but of course it would need to be.