I got around to taking apart my nokia phone battery to upgrade it with new nicads, nickle metals, alklines or lithums. THe part number is bkl-25 4.8volts. Guess that voltage thing limits me to 4.8 volts?
It looks like 4 aa cells in two rows of two hooked in series. THe two outer contacts are hooked to the battery terminals directly, the inner terminals, one to a diode red/white clear one and the other inner terminal to a resistor to the same side of the battery as the outer terminal.
Basically the battery does not hold a charge and when it did, use was limited to 8 hour standby and a 3 minute call or 3 15 minute calls from the off position before the low alarm went off.
I bought a higher cap battery from an online store, but it was a mini nickle metal and the results are just a bit better. I want to upgrade it since the battery thing is large enough for aa cells to something I could leave and use as needed. I normally do not receive calls and use it for outgoing. The idea was to use the lithum aa cells mentioned here. When they die or are used up, just replace them. The thing that holds the cells pops right open with a knife. It wasnt glued, welded or sealed in any way.
Thanks for the suggestions.