Battery help

[Skyline5709]

Hi all a quick question,probably a daft one but I have a 48v 30ah battery, I was wondering will it be OK to use on my 750w bafang bbs02 as the controller is 25 amp thanks

 

[Benjahmin]

It depends on the maximum current output rating of the battery. With a 25A controller ot needs to be at least 30A. Don't confuse this with the 30ah rating, that's the capacity.

 

[Nealh]

Depends on the battery BMS continuous rating.

 

[harrys]

You need a battery that can put out 30A. That's relatively easy with a 30Ah pack if the seller is honest. Not going to bore you with the math, but as long as they use high current cells, you'll get the current..
.
Back in 2015, I bought a 48V12ah pack that was rated for 30A for my BBS02 Also have a tiny 52V6AH pack also rated for 30A. Both will deliver 25A.

 

[Skyline5709]

You need a battery that can put out 30A. That's relatively easy with a 30Ah pack if the seller is honest. Not going to bore you with the math, but as long as they use high current cells, you'll get the current..
.
Back in 2015, I bought a 48V12ah pack that was rated for 30A for my BBS02 Also have a tiny 52V6AH pack also rated for 30A. Both will deliver 25A.

thanks for the replies it's got a 35a continuous bms is that ok

 

[harrys]

I've never seen more than 25A measuring with an peak current wattmeter from my first BBS02 from 2015. I believe Bafang has lowered the max current too on newer motors. I think a 35A BMS is more than enough.

 

[Benjahmin]

35A bms is fine. However are the cells themselves up to it? Do you know what cells are installed in the battery, or at least what the manufacturer says they are?
I would suspect that a battery with 35A bms and a controller with 25A max demand you should be OK. Thing to look out for is voltage sag when drawing maximum power. There's bound to be some but too large/quick a sag can indicate long term damage being done.

 

[Skyline5709]

35A bms is fine. However are the cells themselves up to it? Do you know what cells are installed in the battery, or at least what the manufacturer says they are?
I would suspect that a battery with 35A bms and a controller with 25A max demand you should be OK. Thing to look out for is voltage sag when drawing maximum power. There's bound to be some but too large/quick a sag can indicate long term damage being done.

They cells are samsung 21700 the sag seems normal compared to my other batteries

 

[Nealh]

thanks for the replies it's got a 35a continuous bms is that ok

Yes it is ok.

 

[harrys]

Samsung 21700 cells in a 48V30AH battery would mean a 13x6 cell matrix assuming 5AH cells. A very nice battery,

At 25A, each cell needs to provide only 4.1A, which is well within capability.

 

[Benjahmin]

There ya go.