Kill a Ni-MH
- Thread starter how2
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Locoboy5150
Flashlight Enthusiast
- Joined
- Nov 3, 2009
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- 1,102
Take it to a battery recycling center or to a store that accepts old batteries for recycling. My workplaces have all had battery recycling bins in the various buildings.
TooManyGizmos
Flashlight Enthusiast
Might depend on what you intend to do with them after you kill em.
Are you doing experiments ?
Are you doing experiments ?
jhellwig
Newly Enlightened
Dead short for weeks. I have left several flashlights on for days and they always came back. It really didn't hurt the already bad capacity. I suspect that several weeks may do it.
45/70
Flashlight Enthusiast
As far as I know, the only way to get a nickel based cell to read 0.0 Volts is to have damaged the separator in such a way that it is shorted out internally. Otherwise, as long as there are chemicals inside the cell, and the electrolyte is not 100% dried out, there is going to be some voltage.
Dave
Dave
Mr Happy
Flashlight Enthusiast
If you leave it shorted for long enough it will eventually get to 0 V. I came across some Targus brand 2700 mAh cells that were packaged in a charger without any plastic insulator to isolate them. Those cells read 0.000 mV on my meter. I couldn't even get a microvolt out of them.
Kaamos
Newly Enlightened
Contrary to what I have read on these forums, I have never been able to "kill" a NiMH by totally zeroing its voltage. This may happen forgetting an incan flashlight on for extended periods of time. I have done this a few times with a 2AA light and always both batteries have recovered after a refresh cycle on a BC-900. It takes a little tweaking to start the charge, but after that, they've always worked. One of the batteries (the weaker one) has probably even experienced reversing, as some power has been pushed through it after it has been completely depleted.
I haven't done this on purpose, not with good, new batteries, so I can't really say how much of the lost capacity comes from this abuse. I haven't seen much change, though. Anyway, it seems that a NiMH won't die of this kind of electric abuse. Maybe it "gets sick", I don't know, but I've never seen a sudden death. Does anyone have more substantial numbers or something on the damage that should occur to a NiMH battery during a rock bottom deep discharge? If it isn't the capacity or current output, maybe it's the self discharge rate?
I haven't done this on purpose, not with good, new batteries, so I can't really say how much of the lost capacity comes from this abuse. I haven't seen much change, though. Anyway, it seems that a NiMH won't die of this kind of electric abuse. Maybe it "gets sick", I don't know, but I've never seen a sudden death. Does anyone have more substantial numbers or something on the damage that should occur to a NiMH battery during a rock bottom deep discharge? If it isn't the capacity or current output, maybe it's the self discharge rate?
Kremer
Enlightened
Reverse charging a cell is a good way to get it to grow an internal short, and never work right again.
Kaamos
Newly Enlightened
Ok, but that's obviously a possible outcome, not an inevitable result of reverse charging. But are there other effects that will always make a gradual decrease of performance, so that a reverse charged battery is never going to be quite what it was before the event? Or is the internal shorting something that can also build up gradually, so that every deep discharege or reverse charging will just bring the inevitable death closer, just lurking around the corner but not yet showing its ugly face?
Can someone suggest good reading about NiMH battery chemistry? Why not different lithium chemistries as well. I mean, not just how to charge and use them, but the actual chemicals used, crystallization effects in the different phases of charge and discharge etc. Not that I'd like to found a factory of my own, I just happen to be interested.
Kremer
Enlightened
Oh yeah, reverse charging one time isn't a sure deal for cell death, but from what I have seen it doesn't take much if anything more.
n3eg
Newly Enlightened
Wrap in in aluminum foil and store it in your toilet tank...
TooManyGizmos
Flashlight Enthusiast
Naaaaah ... that won't kill em ......
That'll just make em GLOW in the DARK .
That'll just make em GLOW in the DARK .
