I have read through this thread and would like to comment on Evil Homer's question in Post #91. He asks about using a two cell pack with a high current diode.

I think this is a great idea! High current silicon diodes are cheap (a 3 amp 1N5627 BK is $0.95 ea for one from Mouser) and will drop voltage exactly 0.7 volts. Put this with two 3.3 volt cells and you get a stable 5.9 volts. Sounds perfect.

Stan