Reviving old cells

[dangermouse]

Hey guys,

Has anyone got any ideas on reviving old Intellect 3600mah Nimh battery packs? I've got some I'd like to revive/rematch for a project.

I've tryed cycling a few at 5amp charge, 3.6amp discharge (highest my chargers will do), and have gotten one from about 60mah upto 1700mah after 5 cycles. Obviously a few dead cells holding them back.

I'd kind of like to exercise them a bit and identify the obvious dead cells before breaking them down to be matched. Try to save wasting time cycling dud cells on the matcher if you know what I mean.

Would slow charging help?

[aeiou]

If you have a dead cell in there, your pack will never respond correctly. I've had NiCd cells come back before, but I haven't had the same luck with NiMh. Your best bet is to work with the individual cells. If they don't respond after a couple of cycles, they are most likely shot.

[filzemail]

I agree with the previous poster. If there are any dead cells in the pack you might as well save yourself some aggravation and just dissasemble the packs and just use the best to make better packs. As long as there is either a weak or dead cell in the pack you are just spinning your wheels trying to revive them. Older packs also do not have good capacity or cannot put out current like they used to. Even the best cells you get out of the packs may not be worth the effort to reuse.

[dangermouse]

Yea, I'm certainly not expecting miracles. There are 10 packs all from the same original batch of cells.

I can automatically cycle the packs on the chargers which is what I have been doing, so they just tick away in the background. I figure at the very least the cells are getting a gentle exercise and they have definitely improved a bit.

Once all the packs have been cycled a bit, I could always turn down the peak sensitivity on the charger, followed by a 20amp discharge... That should warm up the duds and make it obvious which cells are straight for the bin. EDIT: Actually if I went through and peaked each cell in the pack before the discharge it would make it even more obvious.

I do have a Competition Electronics Turbomatcher 4/35. That is where it gets more fiddly and time consuming, breaking down the packs and running all the single cells through.

[junkman]

I'd say the best way to revive them is chuck em in the trash and buy a couple $17 2s 5k lipos and have fun. Unless they have sentimental value or something I just can't see it being worth the time to mess with it. I had a huge batch of packs that I'd been planning to go through and try to make a few good ones. My plan was to charge them what I could, then take a 12 1157 bulb discharger from the good ol days and try to cycle them with that. I was going to use a temp gun and meter on each cell to try to figure out the good ones. I ended up trading 56 nimh/nicad packs to a dude for for 1 4k 2s, he was planning to do the same. That was the best decision ever, got rid of a big ol box of batteries, and got something I can use. I recently got back into racing, and its pretty crazy to think you can run the c-main, transfer to the b, transfer to the a, with the same $17 pack and still run 3rd in the a and not dump.

[dangermouse]

Hey Junkman I understand exactly what you are saying, with lipos being way better and all.

The problem is that I wanted to run saddle packs under a Cat XLS body, which isn't exactly roomy.

[notme]

I have found the same thing with Nimh's, just wouldnt come back. Yes I dug out some red 1400 sc's and managed revive them, 2 packs. They are still in my nitro starter box and get the job done.

[SoloGraphix]

Hey Junkman I understand exactly what you are saying, with lipos being way better and all.

The problem is that I wanted to run saddle packs under a Cat XLS body, which isn't exactly roomy.

For $28 bucks, you will be happy you spent it!!!

http://www.hobbypartz.com/98p-25c-6000-2s3p-saddle.html

[SoloGraphix]

http://www.hobbypartz.com/98p-25c-4800-2s3p-saddle.html

This one has a smaller footprint due to the lower capacity, might be better.