On Thursday, October 11, 2012 7:25:17 PM UTC-7, wrote:
My K2 w/o BMS has just two terminals just like any Pb acid, so I don't see how a charger can monitor each cell. I also don't know what a balance plug is, so I'll stop commenting. I'm just relaying what K2 and B-T Jr. told me.

Okay, perhaps when they assemble/manufacture these batteries they ensure the cells are very well matched. The typical A123 and LiFe batteries used in RC have a special plug, often a JST-XH/(JR in the case of ElectroDynamics) type that allows the cells to be balance charged when using a capable charger. It is an absolute must in the case of Lipos (for safety)but with Life/LifePo/A123 you can get away without balance charging to some degree.