Swagtron EB-5, 5A charger ok?

[Skate Daddy]

I have a Swagtron EB-5 commuter bike.
It takes forever to charge with the 42V 2A charger that comes with it.
Would there be any harm in using a 42V 5A charger to speed up charge times? (It's a 36V 8ah battery)
Thank you

 

[amberwolf]

Depends on the battery's design and cells.

A couple of the possible problems you may encounter:

If it has a BMS, higher current will heat up it's charge FETs more, which may cause problems either immediately or eventually.

If the cells aren't made for higher current charging, they too will heat up, and age faster. If any cells have problems, those may be exacerbated by it.


FWIW, an 8Ah battery that is well-balanced will take only about 5 hours to recharge on a 2A charger, from completely empty.

If it takes much longer than that, it's probably unbalanced from either age or defects (or both), and so the BMS is having to rebalance it which may take a very long time (hours to days + ).

IF that's the case, a higher current charger wont' change that--it may even make it worse as the already-problematic cells age faster from the higher currents. It'll only speed up the initial charging portion.

 

[Skate Daddy]

Thank you. I guess I'll stick with the current charger, I don't want to fry the BMS. I wanted to change it so that it would charge as fast as my 36v 14ah battery, but that one handles 5A. Thanks again.

 

[amberwolf]

Thank you. I guess I'll stick with the current charger, I don't want to fry the BMS. I wanted to change it so that it would charge as fast as my 36v 14ah battery, but that one handles 5A. Thanks again.

It's possible your other battery will, too, but you'd have to find out what it's capable of from the manufacturer (since it's unlikely to have markings on the BMS that will tell you much of anything; the cells *might* be marked with their brand/model, but no guarantee the marking is correct since cells get rewrapped/marked too often, to make them look better than they are).


A 14Ah battery at 5A should charge in around 4 hours or a bit less, not including balancing, from completely empty. So it's not that much faster than your 8Ah battery at 2A taking around 5 hours or so.

 

[Skate Daddy]

Thanks again. The thing I noticed between my Sondors and the Swagtron was the difference in the time to get the battery back up to full after riding. If my wife and I ride for an hour and come back and put them on the charger, the Swagtron takes at least 2X as long to get back up to full. This difference only matters to me because I take the bikes to Burning Man and charge them from a generator, so that extra hour of charges is an hour on the generator. At home, it matters not. I think I'm just going to consider the extra time as the fact of the matter, and work on other things. Thank you!