battery help
 

anyone know of a way to help out or bring back a bad nimh cell i have 1 or 2 bad cells in my radio pack and i am looking to try and get them back in the game 1 is at .467 v and i cant seem to move it .it takes about 25-50 ma then stops charging . i tryed .5a , 1a , 1.2a ,1.5a and no luck i am guessing its a gonner

i got my own answer and here it is if anyone else wants to know . and if u want to know more theres a link at the end to more info . thx me

If you accidentally over-discharge your pack
Cells that have been over-discharged should immediately be slow-charged to minimize any damage from possible cell-reversal.

This damage occurs when one or more cells in a pack has a lower voltage level than the others during a discharge. If these lower-voltage cells reach zero volts, continued discharging actually reverses their polarity and they are force fed a reversed-polarity charging current. This can damage them. You can help to avoid this by occasionally rebalancing the cells in your packs. Over-discharging can still accidentally occur though and immediately slow-charging the cells (at a 1/20C-1/10C rate) can help to minimize any damage. No need to fully charge the packs at this low rate. Just a 10%-20% charge to bring any cells out of reversal and then you can finish the charge normally and either use the pack or discharge it to 0.9V/cell and store it.

http://www.camlight.com/techinfo/techtips.html

its been a hard fight but i am up over 1.1 v now . it hasent been easy this isnt somehting u will do for cheep cells .

I had a similar condition when attempting to solder up my first battery pack.

I had read online that it was good to discharge them before soldering. So I did just that and discharged them to around say 1.0v (or whatever it was) and proceeded to make up the pack. Checked and rechecked and rechecked the volts and everything seemed proper (3.4v ish per 3 cell pack). As I went to finish up the pack (shrink) a few days later, I checked the voltage one more time and one side of the pack was around 2.Xvolts. Pack sat on my bench, there was no loads on it. So I unsoldered the one cell in question and checked it.

It would start out @ 0.70v and immediately drop down to about 0.20v and hold there. After about a week or so of sitting on my bench it was now holding a charge of 0.90v, but would also slowly drop down to 0.89v and lower. I have not attempted to charge it up at all. Because I would have to resolder and charge up that one cell on its own.

So, basically im going to order in a new single cell (plus $10 shipping) and not bother discharging that one to solder it to the pack, because that seemed like a waste of time and money. I had made up another pack w/o discharging before soldering and it came out fine.

Unless of course, I give it a small shot of charge and see what happens. I would use my older charger for doing this. I dont want my new charger to go loopy on me...lol.


edit: Thanks for the link btw. Just took a look at it and I think I may want to spend some time reading it.

this sounds like the thread for battery talk and i wonder if I could ask a question.

I am just getting back into the sport, and the only batteries I can make work with my old off-road elec car are my really old nicd 1400 mah ones, but they don't last of course given age.

I bought a new DuraTrax Piranha Digital Peak Charger and a couple of new nimh 3000 mah batteries but cannot seem to make them work with the car, they don't seem to take a charge, but have set the charger up exactly as instructed.

Any input would be helpful?

This may sound silly but did you press and hold 'E' and wait for the beep sound to tell you that charging has started. And once it does, the lcd displays a totally different set of information

Yes, I did do that, pressed the 'E' and got the beep. Thanks