On Wed, Dec 15, 2010 at 3:46 AM, RussellMc wrote: > That was also my immediate thought. > > However, if pack lower limit is set at 4.4V and one cell is at zero > Volt then others needs to be at an average of 4.4/3 =3D~ 1.47 V =3D fully > charged. > ie with 3 x very fully charge cells fresh off the charger and one with > totally zero output it is possible to JUST drive the 4th cell into > reverse bias. In real; world situations with say even 3 x 1.3 V/cell > the 4 th cell needs to be at 4.4 V - 3 x 1.3 V =3D 0.5V. This is not a > healthy voltage to run a cell down to, but reverse biasing during > discharge would be rather hard to manage. Add more cells and it gets > easier do reverse bias a cell. The likelihood of that happening here is very low. My charger is a "smart" charger. It'll balance the cells very well. I'll know if there's something wrong with one of the cells. So assuming that, at the very least, each cell is within +/- 30% of the average state of charge, everything will be fine. In reality, I've always (during load testing), seen my cells discharge in a very well balanced fashion. --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .