Bring old batteries back to life

[minijosh]

6 cell 4200 nimhs
Just started charging my batteries after returning from a year deployment and I've killed one pack already. I let it trickle charge for a little bit to put juice back in it and I then cycled the pack. One thing I didn't do was watch the pack so I lost this pack.

One cell had melted plastic all around it so I'm considering that pack dead. I'm using a duratrax intellipeak ICE charger. It's been a good charger in the past so I thought it would be ok to use again.
So with the other pack I have, I put it on my Tekin 112A and just didn't do anything except watch the red button flash so it would trickle charge.

So my questions are did I kill that one pack? Has anyone had problems with this charger? How do you bring your packs back to life?

[Trubble]

About all you can do is just what you did. Charge at a lower rate (trickle charge if necessary), and pretty much hope they come back. Bad part is, if you read up on cell reversal, you'll find your cells that go belly up probably did so in storage, so there's little hope even good charging techniques will save them. But, you're doing as well as you can do, from the sounds of it.

[EeePee]

Hey, you've been gone for a while. Welcome back. They always come back...

Try to remove that cell from the pack and run a 5 cell pack. Better than nothing. Or add some cells to your other 6 cell pack.

[Manning]

Batteries don't last for forever, and they do indeed go bad just sitting around. Just how it is.

[Charlie-III]

I would first check each cell voltage BEFORE charging, if you have a low one (say, 0.9 volts) make sure you charge it slow.

I would have to look up my old NiMH specs though, 0.9 volts may be OK.

Yes, a slow charge rate (may take a couple of hours) is the best bet, let it sit, then discharge at a low rate.
Do this a couple of times before doing higher charge/discharge rates.

I brought back a number of 20 year old NiCD & NiMH packs using this method (the NiMH's were not 20 years old, maybe 12?)

[Trubble]

Originally Posted by EeePee

Try to remove that cell from the pack and run a 5 cell pack. Better than nothing. Or add some cells to your other 6 cell pack.

Yup, did that just last night, finally got to where I had a shorted cell and it just wouldn't come back. So now I have a 5-cell NiCad pack (dating back to the late '80s). Ran it in the AX-10, and it ran fine. Run time was a bit short, but I don't think I've ever stuffed more than 800-1,000 mAh back into these batts when charging them, so I expected they'd putter out pretty quick.

So if you have a 5 cell 4200mAh pack, you should be fine. Mine ran a little slower, but not really what I'd call a dramatic difference (from my usual 6-cell).

[minijosh]

I think I might have fried it though. Seeing the melted plastic from the stick pack is all I have to go off of.

[Trubble]

Originally Posted by minijosh

I think I might have fried it though. Seeing the melted plastic from the stick pack is all I have to go off of.

Oh I agree that cell's probably a goner. The rest of the cells in there are probably okay, but if recreational battery pack rebuilding isn't your idea of fun, then yeah, you should drop that pack off at say, Batteries Plus for recycling and go buy a new pack. Time for some Elite LiPo's from cheapbatterypacks.com? I mean, you've already got the Ice charger, jus' sayin'.......
But what I believe is that if you had torn that pack apart and checked individual cell voltages before you even tried to charge it, I'm certain that you'd have found that cell to be shorted or reversed, and I seriously doubt there's any way you could have brought it back. So if your other pack is also very low voltage, and you think a cell (or three) in there might have gone bad, my opinion is that you can charge at a trickle or very low amperage all you want, if it's already bad, there ain't much can be done to make it good.
I very seriously doubt you did anything wrong, and I very seriously doubt there's anything wrong with either of the chargers you mentioned. There could be, but I doubt it. On a 4200mAh pack, there'd be no harm in turning your amps down to 2 amps to get moldy-oldies going again. If your charger lets you adjust your Delta Peak voltage, I usually run my Onyx 230 at 4-5mV for NiCads (doesn't apply to your batts, disregard), and 2-3mV for NiMh's.

[minijosh]

Just found another pack with a cell that blew it's top. Man this sucks!!!!!!! I'm just glad that the cell is on the outside of the pack,easy to remove.

[2500hdon37s]

just cut you're losses and use this as an excuse to swap to lipo's

[bob1961]

yeah what some have said, check voltage of each cell to see if any read no voltage....that will be a bad cell most likely....i have 1500 elite nimh batt's and after a winter off i use a .2A charge setting to trickle charge them, it takes bout 10 hours some times before i charge at regular rate of .75A....i never charge more then 1.0A ever........bob

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[minijosh]

Yeah my batteries have been used for touring car racing so they've been around the block. Just sad to give up my old cells. I don't think I'm sold yet on lipos, I like the heavy weight in my rigs.

[2500hdon37s]

Originally Posted by minijosh

Yeah my batteries have been used for touring car racing so they've been around the block. Just sad to give up my old cells. I don't think I'm sold yet on lipos, I like the heavy weight in my rigs.

a light weight lipo allows you to put the weight in even better places, like down low on the axles, and you dont have the high COG!