On Thu, Mar 10, 2011 at 8:17 AM, Olin Lathrop w= rote: > Jonathan Hallameyer wrote: >> Except rather than individual >> transformer and a common bus for everything, I want to wind 5 windings >> on a core, > > How are you going to control the power to individual batteries then if th= ey > are all on the same core? > > Looking at slide 8 of the battery workshop pdf, I was under the impression that all the switches operate in unison, and each cell voltage would be applied across each respective winding, but since they all have the same turns ratio, current would flow out of cells with a higher voltage, and current would flow into cells with a lower voltage, balancing them in the long run. After the on period, all the switches turn off, current in the windings decay, and any energy stored in leakage inductance is dissipated in the snubber circuitry on the switches. Obviously a highly imbalanced cell could draw/source an excessive amount of current, so a fuse/polyfuse would be used on each batteries winding. The 5th winding would have a the average voltage of the cells on it(assuming 1:1 turns ratio for the 5th winding to the battery windings), for monitoring or sharing with other packs, or individual switches could be turned on, and the voltage of that cell would be on the 5th winding, provided its not more then 1 diode drop higher then the lowest battery in the stack, and even a 0.5V imbalance would be quite significant. Even if I have to move to an individual transfomer per cell as shown in the .pdf, I guess my questions for magnetic material seleciton would still stand. Thanks, --Jonathan Hallameyer --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .