Hello there. I got my NZ90 from a friend. The unit has been lying around for more than half a year without any charging. The unit ended up having a very short battery life for the bp500 and a totally useless backup battery. I tried to charge it a couple of times, leaving it overnight even just to see if there's a chance that the battery may still function, but to no avail. I removed it and checked that it is a rechargeable Lithium Mang... button battery, 3 volts ML2020. Can't find anyone selling it on the net. I checked that the standard lithium battery, not rechargeable ones, have the same 3 volts, but instead of having the original 45 mAh, it has 200 mAh. Is it possible for me to just replace it with a battery that's not rechargeable? Anyway, those lithium button batteries can last at least a year or so. It's acceptable to have it changed once a year. Can anyone verify if this will work? Will it affect my Clie?
I hope this is possible coz it's difficult when you have to remove the bp500 and all data will be wiped out.
I guess I´m having the same issue. I bought a used NZ90 and traded my TG50... The NZ I´ve got has also a very short battery life; the video application won´t even start after charging it to 100%...
Try the bp500 on ebay for 30$.. A new one on the Sony website costs around 45$.
NZ90 backup battery dead, any replacement? 
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