60v 40A li ion battery with 2A charger

[heavylildude]

Hello again all,

So I was ordering a local supplier a custom 60v 40A li ion battery with 50A BMS, the battery itself is pretty nice, but the thing is he only provided me with 2A charger.. Pardon my noobness but does it mean a full charge will require 20 hours? Should I look for higher amp charger?

 

[amberwolf]

40A, or 40Ah?

world of difference:

A is just how much current hte pack can supply.

Ah is the capacity of the pack.

If the latter, then it will take more than 20hours at 2A if you charge from empty, because it will taper current off as it approaches full, *and* there will be hours (at least) of balancing time, if it is not balanced at that point.

BTW, if it's a 40Ah pack, it must be quite large, perhaps up to (or over) 35-40lbs. I have two 20Ah packs on the trike, and each just about fills a 50cal ammocan.

 

[heavylildude]

Hi, thanks for replying.. yep.. 40Ah, do you think I should find charger with bigger current or better split my bms (so I just charge using 2 charger) ? This is the fuel for a 60v 1500w motor..

*) Measured about 30x30cm, 7cm thickness, at around 13kg

 

[amberwolf]

I'd find a better charger, as long as the BMS's charging port is designed for higher currents, and the pack is designed to charge at higher rates (depends on the cells).

The Satiator by Grin Tech http://ebikes.ca can do up to 8A for a "48v" pack (full charge at 58.4v); I don't know what your full charge voltage is on that pack. If it's higher, they have a higher voltage version but it doesn't do as high a current at the higher voltages.

There are also other high-current chargers, but as the voltage also goes up the cost goes up.

Paralleling chargers doesn't usually seem to work very well; though you can probably series a few low-voltage high-current chargers (or rather, one charger and several fixed-voltage power supplies), with the limiting factor being hte lowest-current unit.

 

[dogman dan]

Chances are good your bms can handle up to 8 amps, and nearly all should handle 5 amps. Long time to charge, even at 8 amps.

There should be a specification for max charging amps on the page you bought from. Or just ask the seller.

 

[wesnewell]

Standard charge rates for many 18650's is =<0.5C. Higher charge rates swill shorten life. Still, with a 40ah pack, 10A would only be 0.25C charge rate, so if your bms can take it, then, well you can do the math. I wouldn't go over 20A even if the bms can take it if you want a long life.