[quote name='blastexx;29781]Battery pack cells are balanced when all the cells in the battery pack meet two [URL=conditions:If]conditions:If[/URL] all cells have the same capacity' date=' then they are balanced when they have the same relative state of charge (SOC.) In this case, the open circuit voltage (OCV) is a good measure of the SOC. If, in an out-of-balance pack, all cells can be differentially charged to full capacity (balanced), then they will subsequently cycle normally without any additional adjustments. If the cells have different capacities, they are also considered balanced when the SOC is the same. But, since SOC is a relative measure, the absolute amount of capacity for each cell is different. To keep the cells with different capacities at the same SOC, cell balancing must provide differential amounts of current to cells in the series string during both charge and discharge on every cycle.[/QUOTE'] source: Wikipedia.Also of interest re. Lipo protection, both circuitry and physical: over discharge, cell swelling, cell puncture, overheating. Also re the Eken's charger: output capacity relative to charge rate and power-on board draw.