LiFePo4 pack configuration and charging

[sharkmobil]

Looks like I got a decent deal on 48 3.2x4900mAh cells. I would like to build a 36v/20Ah pack out of them.

Couple of questions:

1. They are rated at 2C. Does it mean I can expect to get 10A from each cell safely? Would I be better off paralleling them in groups of 4 and then serializing in 12 (vs 4 of 36v packs)? Is it alright to let BMS manage 4 parallel cells on each string?

2. Can I use a Li-ion charger with a corresponding resistor to charge my 4p pack? Something like that perhaps: http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=4470 ?

Thanks in advance, this is a great place to learn.

 

[sharkmobil]

I guess nothing to take away or add to the aforementioned?

 

[K-ray]

Hey Sharkmobil,

Yes you should configure it as one 36V 20Ah pack. Build the 4 cell parallel blocks then series them.
Get one of Gary's soon to be released BMS /CMS boards It WILL deal with the parallel groups.
It will be in kit form so you'll have to assemble /solder.
You'll need a good quality 36V lead acid charger, or a variable power supply rated up to at least 45V
(5-15 amps at that voltage would be preferred for your capacity).
I'm no expert but that's what I'm doing.
Good Luck

Kevin

 

[fechter]

Right about the grouping. Parallel first, then series.

The charger in the link looks like it's for Lithium cobalt cells. Not sure what chemistry your cells are.