DeWalt battery unit recovery

[Barry]

This morning I decided to re-cycle an old DeWalt battery pack that would no longer take any charge. It was a 14.4V battery unit for a drill/driver.

 

I decided to recycle it as a result of reading the leaflet that came with a new battery unit that I ordered from the internet (39 quid - Ouch!).

 

I discovered the nearest DeWalt service agent from the DeWalt web site and took it there. Whilst there I asked the guy what he thought about the thing I had heard about rejuvenating old battery units (on here as it happens).

 

He said he could have a look at mine with a machine he has in the back for the purpose. Unfortunately he couldn't do anything with mine because there was not enough charge left in it for the machine to read so it could not respond. he said one of the cells was probably completely dead so it was scrap really.

 

So - having already junked one expensive battery unit a few months ago and now having got rid of another today, if I have any more that have the rapid red flashing light on the charging unit, which is the indication of a major battery problem, I shall be straight back to that service agent to see if he can bring it back to life again without me having to fork out for a new unit

[Serenity Malc]

Yello,

 

Do you have any idea what the service agent does with the batteries to revive them ?

 

Malc.

[WotEver]

... if I have any more that have the rapid red flashing light on the charging unit...

 

I was down our local tip a few months back and found an 18V DeWalt NiCad placed on the ground next to one of the skips. It accidentally fell into my car. When I got it back, I put it into one of the 'intelligent' DeWalt chargers and got the fast flashing light. I lifted it out and dropped it back in and the light flashed at normal speed until the battery was charged. It then performed fine. Probably three or four times out of ten when I charge it I have to do the same out-in-out-in dance until the charger is happy, but I've now been using this 'faulty' battery for several months.

 

So... the next time you get the fast flash, don't give up immediately.

 

Cheers,

Tony

[Bill]

Yello,

 

Do you have any idea what the service agent does with the batteries to revive them ?

 

Malc.

 

I have rejuvinated a DeWalt but I believe you can only do it with NiCd, do not try it with any other more modern varieties (Li-ion etc).

 

Basically it goes like this

 

Check if there is any voltage at all (if there is none, check for continuity between pos and neg), if no voltage and no continuity there is a buggered cell and it cannot be revived. Providing either of the conditions is true proceed as follows.

 

Obtain a DC source about twice the one being revived (i.e. for a 14.4v something around the 28 - 35 range), I used a couple of other battery packs in series.

 

Then you take the pos of the source and attach to the pos of the dud battery. The tap the neg from the source a few times against the neg of the dud battery (will produce a few small sparks but nothing much).

 

Leave the cell for a couple of minutes then recharge as normal. Voila, working battery.

 

Done this to a pack which had laid dormant for 4 years and worked like a charm.

[Barry]

Yello,

 

Do you have any idea what the service agent does with the batteries to revive them ?

 

Malc.

 

Couldn't see Malc - he just plugged it into something I couldn't see and looked for a reading

 

 

 

 

 

I was down our local tip a few months back and found an 18V DeWalt NiCad placed on the ground next to one of the skips. It accidentally fell into my car. When I got it back, I put it into one of the 'intelligent' DeWalt chargers and got the fast flashing light. I lifted it out and dropped it back in and the light flashed at normal speed until the battery was charged. It then performed fine. Probably three or four times out of ten when I charge it I have to do the same out-in-out-in dance until the charger is happy, but I've now been using this 'faulty' battery for several months.

 

So... the next time you get the fast flash, don't give up immediately.

 

Cheers,

Tony

 

Tried the same and it worked a bit a couple of times - but times between charging was markedly reduced

 

 

 

 

 

I have rejuvinated a DeWalt but I believe you can only do it with NiCd, do not try it with any other more modern varieties (Li-ion etc).

 

Basically it goes like this

 

Check if there is any voltage at all (if there is none, check for continuity between pos and neg), if no voltage and no continuity there is a buggered cell and it cannot be revived. Providing either of the conditions is true proceed as follows.

 

Obtain a DC source about twice the one being revived (i.e. for a 14.4v something around the 28 - 35 range), I used a couple of other battery packs in series.

 

Then you take the pos of the source and attach to the pos of the dud battery. The tap the neg from the source a few times against the neg of the dud battery (will produce a few small sparks but nothing much).

 

Leave the cell for a couple of minutes then recharge as normal. Voila, working battery.

 

Done this to a pack which had laid dormant for 4 years and worked like a charm.

 

Smacks of electrical wizardry to me - I am an electrical dunce

[stuart]

Reminds me of this YouTube vid..

 

 

 

If you do have a dud battery pack, you can buy replacements for the internal cells - have a google for it.

[Bill]

 

If you do have a dud battery pack, you can buy replacements for the internal cells - have a google for it.

 

I have changed individual cells as well as revive complete packs. However it is not quite as easy to make good connections without a fair bit of work. The packs tend to have the individual cells connected by thin metal strips which have been spot welded to the terminals. Removing the duff cell without breaking the thin strip can be achieved with careful levering but it is not easy. The strips then need to be properly tinned (cleaned off and a thin layer of solder applied) before soldering to a pre-tinned terminal on the new cell. As I said can be done but not a particularly easy job.

 

Hope that helps.

[Keeping Up]

Reminds me of this YouTube vid..

 

 

 

 

Takes me back to the good old days of plugging one lead of a transistor into each of the three terminals of a 240v socket and then switching on. SOmetimes you got a really good bang!

 

Also to the days when I used to repair TV's (in the late 1960's). We regularly had customers storming into the shop demanding to know why their TV wasn't repaired yet; I used to tell them it wasn't safe; I'd then take an insulated screwdriver and draw an inch-long spark out from the EHT cap of the tube (about 20,000 volts or so), solemnly saying that if I let them have their TV back this could happen when they turned it on and could fry them or their wife and kiddies.

[waterworks]

I have changed individual cells as well as revive complete packs. However it is not quite as easy to make good connections without a fair bit of work. The packs tend to have the individual cells connected by thin metal strips which have been spot welded to the terminals. Removing the duff cell without breaking the thin strip can be achieved with careful levering but it is not easy. The strips then need to be properly tinned (cleaned off and a thin layer of solder applied) before soldering to a pre-tinned terminal on the new cell. As I said can be done but not a particularly easy job.

 

Hope that helps.

Yes i found that getting solder to take on these cells is a pain in the bum, i think they are plated or an odd type of steel.

[Chalky]

 

Done this to a pack which had laid dormant for 4 years and worked like a charm.

 

 

Nicads grow dendrites ("whiskers") inside the cells that cause them to fail. What you've done is burn out the dendrite. There was a series of articles in Wireless World in the late 1980 about nicads and how to look after them and repair them. I seem to remember that this was one of the methods mentioned.

[smileypete]

Yes i found that getting solder to take on these cells is a pain in the bum, i think they are plated or an odd type of steel.

They're usually nickel plated which can be soldered quite easily with a little plumbers flux applied with a cotton bud. Plumbers flux works as it's acidic, so use an old soldering bit or a cheap iron.

 

Did some recelling myself earlier this year, pictures here:

 

http://www.canalworld.net/forums/index.php?showtopic=45473&st=20&p=902461entry902461

 

Also tried out tinning the ends of a few old AA batts with solder last night, will upload a pic later if I've time.

 

cheers, Pete.

~smpt~