I'm looking at the eletronics now. I can't for 100% certain say what it is but ..
It has plugs that connect to the battery jig the cells were in. This is DEFINATLY part of the cell balacing. perhaps discharge protection cell balance as well. It does have a thermocouple on the unit, naturally for cut off due to over heat. I don't have a charging base to check thing out. I suspect the charger is may only be a Constant voltage supply. The unit in the battery is pretty substantial and heavy.
There is still a substatial voltage advantage over NiMh. Even at 20C They will probably hold 2.5v(speculating on the 40A discharge graph provided by a123 at 40A/2.6v).
here is a graph of the "Best NiMh on the market" 4300Mah.
http://www.cheapbatterypacks.com/cel...nvid=ELITE4300
1.25-1.2v for half of its capacity at 30Amps. 66.87g each. Say you run 7.2v pack in a car. 6 cells x 66.87 = 401.2G
4300Mah/401grams and 7.5-7.2V for half of its capacity...then down hill from there.
here is the graph for the A123
http://site.buya123systems.com/ANR26650M1specs.pdf
We'd need 3s2p and get 4600MAh. So you effectivly be pulling 15A from each P pack at 30A draw getting 8.7v for about 85% of the packs capacity and a weight of 420Grams. you could pull 80Amps and still get 7.5v for 85% of the capacity. Your looking at roughly the same weight. better voltage and better voltage curve over the discharge vs NiMh.
I don't know how the voltage of other cells vary by load but these seem to change quite a lot 2.5v at 40A and around 3.15 at 10A. That is my biggest issue but my cars speed controller will support 9.6v. so no matter the load I'll never exceed 9.9v really under any load so it'll work ok, I'm just not thrilled with it. I was hoping due to the cells C rating it would hold voltage better and I expected them to be CCCV to 4.1v like li-ion and not 3.6v CCCV with a real running max voltage of like 3.2-3.15