Hi Roy, Thanks for the recommendation. I've seen that site before, and it doesn't address some of the issues we have (for example, this site says that one must wait 6 to 8 hours after charging in order to estimate state of charge based on open circuit voltage. I know that to be false, at least under some circumstances, because we do it in a much shorter time after charge and it is fairly accurate.) So, I guess what I'm saying is this: most battery web sites give a list of handy rules of thumb. They are good for most applications, but they are not absolute limits. If you understand the battery chemistry and the effects of what you are doing, then you can push things further. I want to learn about the underlying chemistry and physics so I can determine the true limits for our application. Sean On 6/16/07, Roy wrote: > Not a book :-) but have you looked at > > http://www.batteryuniversity.com/index.htm > > > _______________________________________ > > Roy Hopkins ZL2RJH > Tauranga > New Zealand > _______________________________________ > > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist