NiMh Batteries in Storage
#1
Tech Apprentice
Thread Starter
NiMh Batteries in Storage
I have 4 packs of NiMh batteries that I forgot I had. They are all new and still in the package. Two are 3000 mah and two are 3300 mah. I've had them for about two years. (Actually, two are sport packs and two packs are matched batteries.)
Anyway, I assumed they are shot. I opened one of the packages and tried charging it. It didn't seem to take much of a charge and it didn't run very well.
Do I just need to throw all these away? Is there anything I can do to make them usable?
Thanks for any help.
Anyway, I assumed they are shot. I opened one of the packages and tried charging it. It didn't seem to take much of a charge and it didn't run very well.
Do I just need to throw all these away? Is there anything I can do to make them usable?
Thanks for any help.
#2
Tech Fanatic
iTrader: (5)
I actully had the same problem about a month ago. found two packs of 3300's. I aslo noticed they wouldn't take much also. Well I charged and discharge and equallized them. What also help was I charged them at 4.5 amps instead of 6. they took more. and left them on a tray for a couple of day's. then charged them again at 4.5. then discharged them again( oh I discharged them at 30 amps) then trayed then charged them at 6 amps. now they take a full charge. I seems to me that it took a bit to rewake the cells up. You could try what I did. I'm also no battery wizzard. I hope this helps
#3
Tech Adept
iTrader: (1)
Drain/equalize them to remove all residual charge.
Charge them at 330 mah (or as close to C/10, where C=mah of batteries, which in this case is 3300) for 14 to 16 hours.
Discharge mildly (say 5 to 10 amps) to 5.4v (.9v/cell) then equalize them again.
If you have time, do another cycle of that 14 to 16 hours.
For the first few "fast" charges, try charging at 1 amp first. Then discharge and equalize again as above.
Sometimes it takes a few cycles to "wake them up". After about 3 to 5 cycles, they should be ready to take in those 5 amp charges again.
Charge them at 330 mah (or as close to C/10, where C=mah of batteries, which in this case is 3300) for 14 to 16 hours.
Discharge mildly (say 5 to 10 amps) to 5.4v (.9v/cell) then equalize them again.
If you have time, do another cycle of that 14 to 16 hours.
For the first few "fast" charges, try charging at 1 amp first. Then discharge and equalize again as above.
Sometimes it takes a few cycles to "wake them up". After about 3 to 5 cycles, they should be ready to take in those 5 amp charges again.