revive niMH

[moe7404]

i have batch of NIMH bats that sat for over a year. tryed to charge about 7 AAs. they would not hold a charge. i have about 60 AAs, about 20 AAAs how do i revive them? thanks.

 

[olds97_lss]

All you can do is cycle them a few times and see if they pick up any life. Charge them, drain them, recharge...

I cycle mine about once a year. I charge them in 4 AA holders, then drain them using a brake light from a car. I started buying only LID (low internal discharge) cells lately as they hold a charge longer when not in use. They work better when using them for remotes, cabinet lights and cameras.

 

[moe7404]

thanks OLDS. i found a way to fix my trouble i think. even though they are low on voltage each has about 1 volt or less. i put 4 bats in a 4 place holder raising the total volts high enough that my dynamite prophet plus LCD would charge the bats. this raises the voltage enough so my DieHard 4 place Ni-MH thinks the bats are high enough to start charging them. and take the charge higher to full volts. i think chargers other than the dynamite might do the same. the DieHard charger only sees the bats as one each, with each one seen as a very low voltage, it appears that some chargers wont charge if they dont see a certen voltage charge.

 

[knall]

Had similar problem w some almost never used batteries, buddies SUPER fancy charger charged em. even though my SLIGHTLY fancy charger did not.

 

[zrock]

That is why i use sanyo Envelopes or ( Duracell with the white top same batt just re branded) They always have a charge when i need them and they will hold a charge for a long time without issues. Over a year and still had a good charge a year in my transmitter and still going strong with no charge

 

[olds97_lss]

I just use a 6 volt/300mah power supply direct to the batteries in a holder for a few seconds. That forces enough juice into them that my old MRC 959 charger will see them and start charging. If I let them drain that much, I charge them, let them cool, drain them using brake lights not so low, cool, then charge again.