"Rechargable" Alkaline: Long shelf life, high power density, limited charging cycles, moderate cost.

The trick to the rechargeable alkalines is to avoid deep cycling them.

If you only discharge them by about 25% (leaving them still 75% charged) and then recharge them, you can get hundreds of duty cycles out of them.

A disadvantage of NiCd batteries is their cell voltage is 1.2 volts instead of the 1.5 volts of alkaline batteries. Sometimes this voltage difference can be enough that a device won't even work on NiCds. A system designed to run on six volts would only be receiving less than 5 volts with NiCds.

Lithium batteries have terrific energy density -- but in terms of cost per watt-hour, are the most expensive and are truly nasty when it comes time to dispose of them.

tanstaafl.