Probably one of the most demanding uses of batteries is in the radio
controlled modeling arena. Those batteries are used to depletion and
recharged more often than you put gas in your spam can. In my opinion, the
expert when it comes to battery questions is Red Schofield. You can find Red
at:

http://www.rcbatteryclinic.com/

Less you scoff at RC modeling, be careful... there are a lot of that fly
full-scale machines.