Hey Guys,

I am still rocking my DeWalt 9.6v cordless drill. I have a DeWalt 21008 corded drill for all the heavy work... The deal is my batteries are lame at best... I came across this link on ebay as to instructions on how to re-juvinate your cordless batteries...

Link to Ebay - Dewalt Cordless Battery Repair

So question is.. Scam to make a quick buck? or will it work... seems like the feedback is positive... so it is probably $4.00 ($3.55 actually well spent)

-CS

 

Interesting. I got an old 12v Craftsman with two dead batteries.

But, I'll bet I fall intot the 10% that it won't work for.

 

Being a techy I've studied different types of batteries and there advantages/disadvantages. I don't know what this guy is selling but, if the batteries are NiCd, which I believe most are, I can give you some info.

NiCd are susceptible to overcharging. If your battery seems to lose it's charge fast, it's most often it's caused by overcharging. Best thing to do is a few deep cycle discharges by letting the battery drain completely. I mean till the drill stops completely. Let it sit a couple hours, making sure it's dead by using the drill. After it's dead let it charge to a full charge not overcharging to much. Repeat this process a few times and you can bring the battery back to life a bit. Don't do this to often though. The battery loses a bit of the holding power.

According to Wikipedia theses batteries are good for about 1000 cycles or more before its capacity drops below half its original capacity.

 

I agree with Koopa. What I understand from poking around on the net is that those batteries form crystals inside when you never let them die completely. As the battery discharges, small crystals form. Then, when you recharge it, the crystals turn back into "electrolyte". However, when you never let them discharge all the way, the crystals get so big they can't be dissolved back into electrolyte. So, a few deep discharges and complete charges may break them down and restore decent function. They say to watch the temp of the batteries as you're charging them. Heat is the enemy. I don't know why, but they all say it is. If the crystals get so big as to cause a short in the cell, you'll need to zap them with high current. I've watch videos of guys using welders, car batteries, etc to zap their batteries. They say it works, but I've never tried.

Lead acid batteries are similar, but to break those cyrstals down you'll need square waves or just plain AC current of various frequencies to resonate the crystals and break them down. I just bought a BatteryMinder that is supposed to desulphate the plates in lead acid batteries. I have a habit of letting batteries just sit and that's bad for them. NorthernTool has them for $95, which is a good deal from what I can tell. Most places they're $150 or more. The really good ones are $700! [img]i/expressions/face-icon-small-shocked.gif[/img]

 

Most cordless drill batteries use a commercial nicad cell called sub-C. 1.2 volts.

If you open the case, there are likely a bunch of them with soldered tabs connecting them in series, and likely a temp probe shrink tubed to one of them.

I wonder if the thing on e-bay just tells you to replace the cells?


Anyhow, fully discharging them and recharging, or using a battery conditioner only goes so far. For a few bucks I bought enough sub-C cells to put new cells in 2 14.4 volt drill batteries. It's just a matter of soldering them in series in the same position the stock ones were, hooking up the wires from the top of the case, and putting the temp probe on one of the cells.

Granted, I don't let the thing charge when I'm not around... and that's a do at your own risk kind of thing (if you didn't watch what you were doing and let something get pinched or otherwise short, or bought cheap cells that were defective, you could have a fire danger).

 

Where did you get the cells and how did you solder them?

I looked into replacing my cells once and found it was pretty pricey to replace them all. Not only that, but I think those tabs are spot welded on or something. Whatever it is, I decided it was beyond my ability to do it. They do sell cells with the tabs already welded on, but they're so expensive you're about just as well off to buy a new battery. I guess if you can figure out which cells are bad and replace only those, it might be worth it. But I'm not sure how to do that.

 

sub-c size is the standard ni-cad size..

I seen homemade battery spot welders. made from an old microwave [img]i/expressions/face-icon-small-happy.gif[/img] I am going to look into getting on and making a battery spot welder.

For now I just am running my drill from a 12vdc / 120vac power supply -- drill works great.. but it has a cord.. but whatever..

 

<div class="FTQUOTE"><begin quote>Originally posted by: CraZySteve

sub-c size is the standard ni-cad size..



I seen homemade battery spot welders. made from an old microwave [img][/img] I am going to look into getting on and making a battery spot welder.



For now I just am running my drill from a 12vdc / 120vac power supply -- drill works great.. but it has a cord.. but whatever..</end quote></div>

[img]i/expressions/face-icon-small-happy.gif[/img] That's funny!

I remember back in the late 90's when cellphones were starting to get popular and reception wasn't always the best, I used to have to use an external antenna to amplify the signal enough to talk inside my house. Of course, I'd also have to plug the phone into the charger to keep it going.... And I'd always wear headphones because the phone would get hot. So, there I sat on my "cordless" phone with 3 cords coming out of it. [img]i/expressions/face-icon-small-confused.gif[/img]

 

Sub C's are very common. They are used in everything from hybrid cars (no joke) to cordless vacuums.

I forgot where I ordered mine, but if you google or search e-bay you will come up with a ton of hits.

They can be had with or without tabs welded on. I got them with the tabs, and just trimmed them back and soldered on a wire, using a normal soldering gun.

I put some photos over on this thread:
http://www.dieseltruckresource...186704&highlight=drill

 

Hmmm.... I took one of my 14.4 batteries apart about a yr ago and got online searching, etc, etc.... A yr later.... I just threw the mess in the trash can. [img]i/expressions/face-icon-small-happy.gif[/img] I have a dozen more, so its not that big of a deal. If I could get all those batteries working again, that would be sweet!