Restoring drill batteries

[baysidetas]

I remember on a previous forum some members claimed to have restored dead drill batteries by zapping them with an electric welder.

Does anyone have any experience with this as I have two dead 12v drill batteries.

[norman]

welcome to our world M8.Think that was asked on the old limited. Maybe somebody on here will remember i dont.....Lots of stuff gone to cyber heaven with that one closing

[BruceS]

Yes welcome to the forum!!!

The method of 'rejuvenating' that type of battery is to somehow hit it with a voltage above the normal in short bursts.
Any battery out of a phone or drill etc is a bit hard to do because you need to be able to connect wires (aligator clips?) to the + & - contacts. (poles?)
If you have a spare pair of hands you might be able to clamp the battery with contacts up in a vice or something GENTLY.
One person holding the contact to the battery (well insulated in case they get hot!) & the other person dabbing on a power source.
Something like a 7.9 battery on 12V. I suggest don't do it if you consider the battery still useable because it'll either work or completely stuff them!!!
I had an old Lexmark printer that had a 24V power brick that was OK to use on small batteries. (AA & AAA etc)
About 10 VERY short pulses of much less that a second each. (cover your face!)
Do at your own risk!

[generdawg]

If you Google: "rechargeable battery fix on youtube", you will get a plethora of listings.

Or you could just go HERE.

dawg

[T1 Terry]

you are far better pulling the battery pack appart, finding which cells are low voltage, then recharging those cells till they are all the same voltage. This is what kills equipment battery pack, the cells get out of balance, if you leave it too long some cells will get seriously over charged and the low cells will be dragged to zero voltage, that will virtually kill the cell.
The high current shock treatment is a very short term fix, get the voltage reversed and it's an instant battery death, do it too much or for too long, the over charged cells will explode.

[RussellB[SA]]

Sounds awfully dangerous to me.

I took my old drill battery pack to Battery World and they rebuilt it (2008 $68).

A lot safer.

I laso bought a new one (Battery drill) from Bunnings for same price.

Be safe.

Russell

[oldtrack123]

hi
I assume we are discussing Nicad battery packs
I would not connect a welder to ANY drill pack unless I had armour on
But Nicad cells do often develop crystal that short out the "cell" internally
A short burst of high current will often clear that short & give extended live with little loss in capacity
I personally have done the same batteries over many times , some are now very old
Rejuvenates are available & basically consist of capacitors which send a short burst of high current exploding the crystal
However such can only be done ONE cell at a time
That may involve getting clear access to every Cell's terminals.

With CARE
[a]Any DC source of higher voltage can be used,I simply use a common old 5A battery charger, that makes it a little safer as the current is limited
Check EACH cell first with a digital multimeter,if not auto ranging select the1.5V scale or the nearest higher scale.,if any show even a very low voltage or one that fades away quickly, they are possibly OK
[c]If any show zero voltage give them three or four very quick zaps ensuring you have the RIGHT polarity [Pos to Pos, Neg to Neg]
[d[Retest ,they should now show a reasonable voltage [0.5<1.2V]
[e]if some fail to show voltage or it fades quickly [in seconds][ give another few zaps, if still do not test as in[d] they are beyond redemption
[f]That voltage in[d]even if 1.2V does not mean they are charged. they may now be recharged as a bank by the supplied charger
[g]if a low % of the cells are not recoverable,they can be replaced as individuals ,
Jaycar among other have a range of cells
[h]if more than a few cells need replacing it would poosdibly be wise to
[1] replace ALL the cells in the pack if you consider competant
[2]get thepack proffessionaly rebuit
[3]buy a new pack
The above is a proven method which I have used for something over 20years
Ps
The small nominal 9V nicads can also often recovered by similar appling the charger to their case terminals

PeterQ

[baysidetas]

Thanks to everyone who responded; you have convinced me not to try the electric welder method, which I was very hesitant about anyway.

I decided to have a look at the youtube link genderdog provided and it does appear at this stage that the method displayed there does work. Just rapidly inserting and removing the totally dead battery from the charger about 20 times resulted in the battery operating the drill. The battery is now on normal charge and I am impatiently waiting for the charge to be completed so that I can give the battery a realistic test under load. Co-incidently the youtube video was of the same make and type of battery.

Barrie :

[oldtrack123]

Hi Barrie
Do you have two chargers ?

All that he is doing is connecting the two charger outputs in series to get double the voltage
Then flashing the battery with the internal shorts
PeterQ

[baysidetas]

There are two videos, one is as you described and the other as I described and used. The battery seems to have charged really well but I will measure the voltage in the morning to see if it holding the charge and then try it under load to test its capacity to deliver.