I Just Resurrected 4 DEAD Batteries for My Cordless Tools!

With a collection of batteries that were useless because they all refused to take a charge, I did some web surfing to find what may be out there before I sent them all off to the recycle program.

What I found was several You Tube' video's featuring exactly what I desired. Well, actually, to tell the truth, I searched through ebay first, looking to see what I might find. While looking through ebay, I noticed several sellers that were selling CD's to tell you the "secret" to restore them back to life. This got me to thinking...hmmm, somebody surely posted this same "secret" at You tube also...and they sure did.

It work perfectly on all 4 of my batteries...I'm a Happy Camper.

YMMV

Pretty cool! Do you always use the 12volt power source to reverse polarity no matter the bad battery voltage? For instance if I have an 18 volt battery that won't charge, still use the 12 volt source to reverse the dead cells?

My understanding is 1-1/2 to 2X the voltage is required.

Series up the number of batteries to get the required volts.

SteveZee wrote:Pretty cool! Do you always use the 12volt power source to reverse polarity no matter the bad battery voltage? For instance if I have an 18 volt battery that won't charge, still use the 12 volt source to reverse the dead cells?

Its the 1.2volt cell (Sub C) you are fixing, not the 18 volt battery pack. Yes, Gotta shock each bad cell with 12v.

009to090 wrote:

SteveZee wrote:Pretty cool! Do you always use the 12volt power source to reverse polarity no matter the bad battery voltage? For instance if I have an 18 volt battery that won't charge, still use the 12 volt source to reverse the dead cells?

Its the 1.2volt cell (Sub C) you are fixing, not the 18 volt battery pack. Yes, Gotta shock each bad cell with 12v.

Ok yep that's what I thought. I'll give it a try and have a spare backup for my drill as I'd already bought a new battery for it.

I got interested in this subject due to my old Makita 9.6v drill. I have 2 charger stations for it, both refuse to work. I'm still not sure if it's the chargers or the batteries. I surfed through a few Youtube vids on the subject myself. ( Youtube vid link above is "private" now...)

I saw a few techniques. One was to zap the battery with a welder, either straight or reverse the polarity first, then zap + to + and - to - . I'm not sure how to do this with my stick welder. It has DC straight and DC reverse ,and high and low leads.

Also saw one where the guy just hooks up two good batteries in series to double the voltage and zaps that way.

I have one good genuine Makita battery from Ebay, and an older one. Unfortunately I threw another one away that might have been a prime candidate.

Anyway, I ended up zapping both batteries with a battery charger that has a 10 amp 12v setting. Then I jammed two 4d nails into the battery leads and just put the 12 charger on it, on 1.5 amp and let them charge for around 1/2 hr. Kept safety glasses on and felt the batteries for overheating.
Unscientifically, it worked! Still don't know if it's the chargers or the batteries. In my total cheapness, I know there's many many Makita knock-off chink batteries for sale on Ebay- cheapest around $19. That drill has served me well for many years, really reluctant to give it up.

I've wanted to do this myself. I've got a few of those Craftsman Die Hard 19.2v batteries that should be renamed Die Soon or Die Easy as they've only lasted one charge before they are rendered completely useless. I've just been afraid of doing it.

How long does it last? I'm thinking they would only go for a few charging cycles before you'd have to zap 'em again...?

rockwood wrote:How long does it last?

Me not know yet. Seems ready to work for a while longer anyway.
I wanted to put up a new post about cordless drills; what's your favorite, etc.
Seems a lot of these new drills look more like a ski boot or something with all the fancy graphics and ergonomic BS shape etc.
That old Makita has served me very well over the years.

Speaking of Craftsman Die Hard 19.2v batteries, I have one that died, maybe 1 year old. The second is on it's way too. You can rebuild them, take them apart,count the batteries, measure them, found what family they are in. Some are subC others are 2/3 or 4/5 C. Amp hours may be written on them too. If it has NICD or NIMH, stay with the same type as your charger will work better with original style. You can get higher amp-hours so they should last longer. You can buy them with the tabs and solder them yourself. Cost wise, not gonna save a lot but you should end up with a stronger power pack.

Its not worth the risk when you can do better

just one example

http://www.batteriesamerica.com/cordless_tools.htm

Take some precautionary measures when fooling with these batteries, mainly protect yourself from a possible explosion. Batteries can explode rather violently and can seriously injure or kill you!
I have used this method myself and have only extended the use of the battery by a couple of charge cycles.
Personally, it isn't worth the risk of injury or worse, versus a fifty dollar bill.
Just my .02

Sometimes you can get a dead battery back to life by putting it in the charger and then plugging and unplugging the battery chargers cord into the receptacle a few times. A few times of that and the battery will start accepting a charge.

Dann757 wrote:I got interested in this subject due to my old Makita 9.6v drill. I have 2 charger stations for it, both refuse to work. I'm still not sure if it's the chargers or the batteries. I surfed through a few Youtube vids on the subject myself. ( Youtube vid link above is "private" now...)

I saw a few techniques. One was to zap the battery with a welder, either straight or reverse the polarity first, then zap + to + and - to - . I'm not sure how to do this with my stick welder. It has DC straight and DC reverse ,and high and low leads.

Also saw one where the guy just hooks up two good batteries in series to double the voltage and zaps that way.

I have one good genuine Makita battery from Ebay, and an older one. Unfortunately I threw another one away that might have been a prime candidate.

Anyway, I ended up zapping both batteries with a battery charger that has a 10 amp 12v setting. Then I jammed two 4d nails into the battery leads and just put the 12 charger on it, on 1.5 amp and let them charge for around 1/2 hr. Kept safety glasses on and felt the batteries for overheating.
Unscientifically, it worked! Still don't know if it's the chargers or the batteries. In my total cheapness, I know there's many many Makita knock-off chink batteries for sale on Ebay- cheapest around $19. That drill has served me well for many years, really reluctant to give it up.

I have a couple of dead 9.6V also that I have been saving to try something like this. Time to put on the safety gear and plug it in remote via extension cord.

By the way I have had bad luck with cheap e-bay batteries for cameras and cell phones. Never again will I buy those. I would only buy from a reputable source.

I have an old Makita 9.6 Volt drill that I have owned since 1988 when I used to work for Delta Airlines. I was looking to purchase a new battery but spending $30+ VS getting a new cordless drill was a conundrum because I have sentimental value to this drill. I purchased a keyless chuck back then and nobody at Delta that I knew at the time had one for their drill as this was the most common cordless drill at the time. They were all where did you get that...? After reading your post I decided I would try it as what did I have to lose?... My old battery would not take a full charge and whatever charge it took the drill was weak but not dead., the chuck would spin but could be stopped easily if you grabbed it.. I first checked the voltage and I had only 4.3 volts. I did not have a 12V battery but I do have a battery charger. I used the charger to zap the battery with it set on 2 Amps which is a trickle charge.. After several attempts I was able to get the voltage up to 6.3V but was unable to get it higher. So I switched the charger to 8 Amps and tried it again. After about 20 taps I got the voltage up to 7.5V so again I hit it another 20 times and got the voltage to 8.6V, then again to 9.1V, not satisfied I hit it another 20 times and got the voltage up to 9.7V... I stopped there, but maybe I could have turned my 9.6 V into a 18V if I continued...lol... At no point did the battery ever get warm, but it did have a slight odor at the terminal end, that electrical odor that is all too unfamiliar if you ever smelled it. I put it in my charger and it took a charge beautifully. The drill operates like new, no chance I can hold the chuck from spinning. How long it will last who knows, but a process I will use over again. I will monitor the battery voltage and when it drops below 9V I will zap it again... What a nice way to save money... Thank you for passing on this vital information...