On Sat, Feb 12, 2011 at 12:20 AM, Lee Jones wrot= e: > > Just a question: > > > > I know things like laptops are using multiple cells in series > > in their battery packs. > > As do radio control aircraft, particularly helicopters, which > use multiple cell Li-Po batteries. > > > But after repeated use and several charge/discharge cycles, wouldn't > > one of the cells start to maybe charge/discharge faster than the > > others? Or have a slightly offset voltage for some reason? In this > > case, applying voltage back to the battery pack (cells in series), > > would charge the cells unequally, no? Or perhaps overcharge some > > cells while undercharging others? > > Yes. Yes. Yes. And yes. > > > Is this a real problem? And how would one go about solving it? > > A balancing charger which charges each cell individually. There > are also balancers (which just try to even out the cells). The > requirement is that the battery pack must have a second multiple > wire connector which brings out a connection to each cell. That > second wiring harness is what is used by the balancing charger. > > The primary harness is the 2-wire one where the series voltage > of the pack is used to power the electric motor(s) of the air > vehicle (helicopter, aircraft, etc). > > Thanks. That makes sense. however, by bringing out a connection to each cell, doesn't that mean that the positive end of one cell is connected to the negative end of another, and when charging those two in parallel, the positive and negative ends of the charger would short at the junction? --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .