reviving dead batteries?

[johnakay]

cordless drill etc batteries.
has any one tried the method of reviving dead batteries as you see on the net.
do they really work and if so how long do they stay charge for.
some claim that they have a chip in which fools the charger that its no longer can be charged?

 

[awemawson]

NiCads exhibit what's often called a 'memory effect' - what happens is a very thin whisker of nickel grows from one electrode to the other and shorts out the cell. A quick pulse of high current will destroy the whisker and allow the cell to live again. Had this recently with two of the three batteries for my Paslode nail gun. A very brief flash across a car battery sorted them and they work fine.

 

[anjum]

Works better if you "flash" the individual cells in reverse first for a fraction of a second, then "flash" them normally for a fraction of a second.
Test the voltages afterwards if it comes up to 1.2 volts then you will get more life out of them. Often there's one or two cells which are beyond recovery by this method, don't keep trying just throw them away.
Be careful in case they explode.
Don't use this method on li-ion batteries.

 

[ford34/2]

(I got a pair of 3Ah lithium ion batts for my milwaukee M12 drill for £37 delivered work perfectly)

Do they do 18V as well -- link if they do please.
Stan

 

[ford34/2]

Brilliant opens a lot of options, + Langy can get originals cheap, imported all paid for a dollar a pound.
Thankyou
Stan

 

[Gareth0123]

I have thumped each one my 8 year old Ryobi One+ 18 volts Ni-Cad batteries a couple of times now. I opted for a 36 volt thump from 3 of my One+18 Volt Li-Ion batteries connected in series. This I have done with absolutely no problems what so ever. A couple of my 5 year old Li-ions now need a bit of TLC, and I understand that'll have to open them up to change dead or dying cells.


Apparently you can give the Ni-Cads a thump from a DC MMA welder or Mig plant with the wire feed roller flipped up to disconnect the drive...... But I am not brave enough to attempt this!

 

[anjum]

Batteries for cordless tools are like ink for inkjets- total rip off.

 

[skotl]

Batteries for cordless tools are like ink for inkjets- total rip off.

That's true. £99 for a Makita drill with two batteries, and £65 for a replacement battery.

I've seen vids before for thumping nicads with a MIG and I'd be tempted to try it myself if/when one of my batteries fails (with eye protection, of course!).

 

[PTvor]

In my experience battery revival schemes like the one in the YouTube video might get a bit more use out of the battery, and cost nothing to try, but don't get your hopes up. They certainly won't return it to as new condition.

Some people have definite needs for battery tools, but generally I think they are oversold and overbought.

 

[johnakay]

found these .for what they cost not worth fannying on with the old .thanks for the replies.
http://www.ebay.co.uk/itm/2-X-14-4V...b91aee&pid=100010&rk=2&rkt=24&sd=141649185712