Making packs from Lipo cells which already have protection boards.

[robinb3141]

Hi Folks,
I'm looking at making a battery pack from six of these cells:

http://docs-europe.electrocomponents.com/webdocs/141b/0900766b8141bf6b.pdf

I need either 2 x (3 in series) in parallel or 3 x (2 in parallel) in series , to give a nominal 11.1V 4Ah.

If they were unprotected cells then I understand I'd need to be using protection / balance boards like this:

http://www.all-battery.com/pcb-11-1V-13A-32051.aspx

However these cells already have an overcharge / undercharge protection circuit built in (details are in data sheet above) and I'm unclear about how they might interact. Can I just wire up the packs (after a topping up charge of all cells to balance them)? If so, Which topology of (3 Serial )x 2 Parallel or (2 Parallel ) x 3 Series is preferable?
All info welcome!

Cheers,
Robin.

 

[hadoo]

The best topology for battery cells is to parallel them first and then make them series. If your cells have electronics which can not been removed, you may have some problem such as tolerances of voltage measurements or even more leakage current. Preferably it is better to use cell with no protections, parallel them ,and use a protection for all of them as one cell.

Hadoo

Design Eng at

http://www.lianinno.com