Thread: Restoring Nicad Batteries

I have several old packs that Have broken cases or the clips are busted (Is'nt velcro wonderful) and I haven't been able to transfer the batteries to good cases as I can't solder the stainless steel contact/connectors.

Is there a special solder and where can I get it?

Any help would be greatly appreciated.

I found this but Im not too keen to have a crack at it myself. I have a phobia of being blown up...
http://www.instructables.com/id/EFLRAJ9JACEV2ZHB0Q/

Originally Posted by rat52

I have several old packs that Have broken cases or the clips are busted (Is'nt velcro wonderful) and I haven't been able to transfer the batteries to good cases as I can't solder the stainless steel contact/connectors.

Is there a special solder and where can I get it?

Any help would be greatly appreciated.

You need to get a good clean surface, emery paper is good, dont use steel wool as you may get a short and lots of flames. Clean it with a good solvent, metho will do the job. Lots of heat and flux and they will solder ok.

Thank you for the prompt replies. It is now filed away.

I was getting so sick of buying new batteries when only one or two of the cells were dead

Is there a way of telling which cells are dead and which are ok?

Dan,

Use a multimeter and check the voltage of each cell. They should roughly be equal except for the ones that are dead/nearly dead (obvious isn't it). Even on a discharged cell it's voltage is around 1.0v +/- a bit. If any voltage is zero it's dead or less that 0.8 - 0.7 volts they are on there way out. This is the measurement i use and i replace only those ones.

Now for the tricky bit....how do you charge all the cells to an equal state...i have a charger that delivers 1.4v @ 100mA and i charge each cell one at a time for about 10 hours...takes some time . After that i use it for a while then charge it in the normal way.

Steve

Thanks Steve, I figured you would use a multimeter but wasnt sure what to look for. The other issue was do I have to seperate the cells to do this?

Dan,

No you don't have to seperate them. Just make sure when putting the probes on the cells you don't create a short circuit. Other than that when you find a dead cell it can be removed and once again be careful not to create a short circuit.

Steve

Tried the freezing routine [24 hours charge - use and then 24 hours again] but did not work for me, but if you can get it to work then good for you.

Regards,
Bob

Dan,

Try this place he might know someone in QLD that can re-build your battery. the place is Batteries Direct and the number is 1300 784 401.

Steve

Hey great thread its of the best Ive read on nicd!
I just bought a set of 20 tenergy 2.4 amp hour nicd sub c batteries off ebay. (I know they are not sanyo but the seem quite good...time will tell)
As soon as they arrived I checked the voltage on every cell.
They varied up to .5 of a volt.
I tinned every tab at the end and soldered a bare copper wire to every positive terminal and the same to every negative terminal.
I then left them for 24 hours.By putting all the cells in parallel with each other the voltage across every cell will become identical after a period of time!.
Once this was complete I removed the bridges wires and built 2x 12 volt packs by soldering the tabs together in the same shape as the original packs doing my best not to put to much heat back into the cells as this will ruin them.
It cost me $50 au to build 2 x12volt 2.4amp hour packs plus a few hours of my time (I class this time as hobby time so cannot compare to my wage (would be cheaper to stay at work for a few hours)and buy reco packs
I load tested them yesterday and am getting more than 2 amp hours out so am happy with them!
Ill take themt into to work next week and give them a workout!
cheers rileyp

Like the idea of equalising the voltages rileyp. Would be interested in a progress report in a couple of months.

I just needed to say thank you to all those who gave Me detailed information about the batteries. I know that the post is old, but it is the vary best i have found. I am disabled, so I am not sure I want to tackle this, but I know that it is possible to repair the batteries, Thanks again!

Dan,

There have been plenty of solutions put forward but a couple that worked for me are..
1. There was a place in Ferntree Gully that repacked Nicads. You could have a look for them. Green something....
2. When I needed a repack for a radio recently I found the lowest cost solution was a complete replacement package from Batteries America. Look them up on the web.
3. Finally if your are so inclined, carefully break the old battery pack apart, go down to Jaycar and buy replacement batteries and build your own battery pack. Forget nicads and use the later NiMH and charge them based upon time.
This might not be the lowest cost but if they have the right batteries in stock it will be the quickest solution and with probably deliver the hightest capacity.

Dave