NICAD Battery discharge / recharge / restore

[zacker01]

so I was watching some videos on You tube that show how to “Zap” your old Nicad Batts back to life using a car battery or even a welding machine by connect the power source’s negative lead to the batteries negative side and quickly touching the batts positive side with the power source’s positive lead... it seems to work but looks stupid dangerous. So I was reading about why the batts go bad.. some sort of crystals grow large and sort of short the battery cells out so they wont take a charge or wont hold as much of a charge. Zapping the batts supposedly breaks them back down to a normal, smaller size thus restoring the battery. then I saw a paper by the Army Corps of Eng. I believe, it was saying how you bring the batts down to about 1 volt then slowly bring them up to a fully charged state to break down the crystals but they didn’t mention zapping them. how would you fully de-charge a battery? Mine are already dead, I mean, they wont turn the drill at all, I would consider these "discharged" but im not sure. Anyone ever restore their tired Nicad tool batteries?

 

[OutLore]

I've not heard about zapping them, but have heard the deep cycle routine with NiCd's, although I think you have to do it multiple times to get the best effect though.

I was also told many years ago that putting NiCd's in the freezer overnight cleared their "memory" problem, and if I remember rightly it did actually work, but not for long.

I only have 1 device with NiCd's these days - a Makita drill/driver - got it on clearance in the UK 4 or 5 years ago for about 70% discount. Unfortunately having now moved to the US, I need to either buy a charger for it, or get rid of it as the charger that's with it is not a switching unit, so only works on 220v. I guess I could get a transformer...

 

[hammertime1]

The zapping them with welders has been around for years and lots of people are doing it with claims of great results. I have personally used someone's tools that had did it and they were working again. Not that I'm condoning doing it! I can see someone getting hurt. (keep in mind I'm not a battery expert) I don't know the lingo just read up and repaired batteries when needed.
The tool battery units , etc aren't like a car battery where It is a big unit in a box (I know it's more then that but best description could think of). Most of the tool batteries use Sub C's wired up in series? I akways confuse the series and parraell lingo. Usally only one of the subs fail sometimes two causing the the whole battery to stop working. Also there may be other electronic components in the newer batteries which fail. That was issue when Sears was having with their Die Hard Tool batteries. (manufacture had it with their own models too from what I read) Someone has pics posted on web of several new units with the same electronic piece burnt up.
You can also take the battery apart and buy whole battery replacement kits for about half price of battery or test your subs and find out which one is bad. Ultimately making the repair for about $2-5.00 depending on your source for
. I don't recommend eBay as a source for the batteries or battery kits regardless of sellers positive reviews. People buy em, they ship fast, work when they charge em so they leave positive reviews three months later the cheap batteries **** out!!! I had it happen with two units I completely rebuilt from eBay sellers. Several good sources for batteries and the one good ebay battery rebuilder on eBay straight up tells you where he gets his if you go to his website. Sadly I got the cheap generic bogus falsely labeled batteries that were made to look like one of the higher end batteries. When I finally got the real deal the attention to detail and overall build was night & day.

 

[Cougar]

Mine were completely dead.
Tried the freezer method, so far they are working good.

 

[KinzeMech]

I've zapped some. It's a short term gain. Within a few charge cycles, (2-3) the problem returns most of the time (75+%).

It's more effective if you open the pack, test voltage on every cell, and zap only the cell that is shorted, but even at that, it has not been a lasting fix for me.

 

[csp]

x2 on zapping being short term. Mine worked properly for one charge cycle after zapping them and returned to not taking a charge.

Maybe I'll try the freezer thing and hope for the best, expecting nothing.

 

[eric_koski]

Go to harbor freight, buy the 18 v replacement battery for 12.99 with a coupon. Pop it open and swap/ solder the cells. Ta Da! Good as new for 13 bucks. Just did 3 and they work great...

 

[skyking]

Go to harbor freight, buy the 18 v replacement battery for 12.99 with a coupon. Pop it open and swap/ solder the cells. Ta Da! Good as new for 13 bucks. Just did 3 and they work great...

That^

 

[wafrederick]

There is also a myth out there and don't do it.It is called taping the trigger down with tape,this can reverse the cells in the battery and ruin them.For longer life,remove from the tool when not in use.

 

[beelsr]

the zapping works but is indeed short-term. i zapped my ewalt 14.4 xr packs when they started dying off. I had a dozen packs so I wanted to stretch them out as much as possible. when zapping them, so easy on the charge - i used a couple lawnmower batteries. you're basically doing edm inside the battery.

zap only for a couple seconds at a time and if you can take apart the pack to zap only the affected cells, that's better still. i got an extra 5-6 months out of most packs this way - daily use and 1 or 2 recharges a pack. but they eventually will die and cannot be brought back to life. i have 2 packs left and they're still running strong (coincidentally?, they have a yellow coverplate, not a black one).

as for the memory effect, this is fairly mythical. it only applies if you have the exact same discharge/recharge cycle, as with a satellite - which is where it was noticed. If you vary the cycles, the memory effect never really applies. NiMH is a better performing chemistry and the improved results are largely that.

also, running the battery down until the drill stops spinning or whatever is bad because the cells in the pack discharge at different rates and when you get one down to 0%, the drill will still be spinning but putting current through a completely discharged cell kills the cell (and then you get to zap it as above) and you're 14.4V tools is now a 13.3V tool.

 

[KinzeMech]

but putting current through a completely discharged cell kills the cell (and then you get to zap it as above) and you're 14.4V tools is now a 13.3V tool.

It's actually even worse than that. Not only does the damaged cell not add to the total voltage of the pack, it's it has high resistance to passing current from the good cells.

Generally speaking, once you have a bad cell like that, you're better off (if it's practical) removing that cell from the pack, and putting a jumper wire in it's place. You will still lose 1.2V from the total pack voltage, but now that bad cell is no longer restricting current from the good cells. I've had a 19.2V pack or two that I've removed a bad cell from, making them 18V packs, and if I hadn't marked the battery on the outside, you couldn't tell the difference.
It's also worth noting, that this only works if you have a smart charger that can charge a range of voltages. Most 1 hour chargers can handle it.

 

[beelsr]

true.

i was thinking of pulling apart all the battery packs and making a couple good ones out of them but just upgraded to bosch 18V LI instead (free batteries pushed me over the edge).

 

[zacker01]

Go to harbor freight, buy the 18 v replacement battery for 12.99 with a coupon. Pop it open and swap/ solder the cells. Ta Da! Good as new for 13 bucks. Just did 3 and they work great...

that sounds like a good idea. but my drill is the craftsman 19.2 v. hey, could i use a 20V battery? or would that burn the motor out? I was under the impression that you can use a bigger battery in stuff, the only difference is what ever your useing the bigger battery on, will run longer. Also, do you know if the HF batteries have the same size / shape cells as the craftsman 19.2v?

 

[zacker01]

how about replacing the cells with regular rechargable batteries, or regular batteries like some duracell AA? I wish theyd make a voltage reducer in a transformer so you can plug it in if need be. Hmmmm how do laptop batteries work? I wonder if you found a laptop transformer and wired it into a gutted battery... if it would run the drill?

 

[KinzeMech]

None of those options will work.

A laptop power supply might produce the necessary voltage, but not enough amperage. A cordless tool under load can pull upwards of 10-20 amps, even more under maximum load.

laptop batteries would not be able to produce sufficient amperage.

AA cells would also not be able to produce sufficient amps, and would be prohibitively expensive.

If one absolutely must have a macgyver type backup plan, take the shell of a dead batt, connect wires to the positive and negative terminals, and a short length of (preferably 10ga) wire to alligator clamps, and you can power the drill from any car battery (12v engine off, closer to 14.4v with alternator charging). Another alternative power source would be an old style (non-smart charger) automotive battery charger set to "engine boost". A cordless tool will run fine on lower voltage, it will just run slower, and probably at reduced power. It will be critical to keep the cord as short as possible. When you're only starting with 12 volts to begin with, voltage drop in the line would be killer.

 

[zacker01]

So its not really worth it to mess around with this anymore than just going on Amazon or to sears and buy a couple of new batteries. lol
its never easy is it?

 

[OutLore]

So its not really worth it to mess around with this anymore than just going on Amazon or to sears and buy a couple of new batteries. lol
its never easy is it?

That's where I am with a replacement charger - gets me thinking that actually i could get a replacement tool for not much more, and have later battery technology!

 

[zacker01]

who knows the answer to this. I got to thinking because of this thread, how a battery works in conjunction to what its powering. Say you had a light bulb from a small flashlight. using two standard AA batteries to power it, now if you were to disconnect the AAs and hook it too a 6V Lantern battery, would the bulb:
A) Blow out?
B) Burn but be brighter?
C) Burn the same but stay on longer because the battery lasts longer?

I'm thinking that the volts of the battery doesn't really apply because the light bulb will only take in a certain amount of Amps... is this correct? Or do bigger volts mean more Amps no matter if you want them or not?
lol Im just trying to get my head around the whole Amps / volts thing.

 

[Laker]

... I don't recommend eBay as a source for the batteries or battery kits regardless of sellers positive reviews. People buy em, they ship fast, work when they charge em so they leave positive reviews three months later the cheap batteries **** out!!! I had it happen with two units I completely rebuilt from eBay sellers. Several good sources for batteries and the one good ebay battery rebuilder on eBay straight up tells you where he gets his if you go to his website. Sadly I got the cheap generic bogus falsely labeled batteries that were made to look like one of the higher end batteries. When I finally got the real deal the attention to detail and overall build was night & day.

Will you please share your source for good Sub C's?
Thanks,
Mike

 

[hammertime1]

Sadly, I don't even remember where I finally got em from it has been so long. They bogus ones were Samsung? It was whoever was making a lot of Sub C's for OEM. Few things to watch for are net and eBay sellers are taking dead recycled batteries and zapping em selling em as new. mislabeling amperage saying they are high output 4000ma or whatever and they can barely put out 2000 or even less. Some things you can go up to higher amperage battery. the counterfeit with a better manufactures name and being pure garbage low end battery. They don't last, get hot fast, etc ( they look cheap).
I bought a lot of batteries from battery junction com
In past so it may have been from them. I use the tenergy rechargeable in my kids toys.(I know it wast tenergy) Bass pro had one of those mutil volt slow universal chargers without automatic shut off on clearance line 7 years ago and I grabbed a few. I got the chart for charging and for the tenergys that can take a bigger charge I just tested to em to figure out how long it took. it's a pain but since the slow charge was suposed to be better figured give it a shot. Still got some of those batteries in toys. Battery junction has a discount code every month too usally like another 3-5 percent off. All battery .com sells em too place called only batteries.com has a hughe selection too. Never saw thene before but don't look the eBay **** I got stuck with orginally. Looks like higher pricing.
I cannot find the place that listed their battery supplier and a few now are just saying grade A batteries or suppliers like Sony and Samsung. Notice I say they said word like. The battery had a long name and was another appliance manufacture. Places that were using were given them a 2 year warranty. I found good rights up about thier batteries too but guess I didn't save any of it. I never had a bad battery from b junction and they shipped fast. I have a few things that need some cells replaced. When I get around to it I will order from Bjunction since I cannot find other info. I wanted to try the Tenegry subs anyways. I used em some of their 153's and they all lasted as long or longer then more expensive batteries. Have some of em in red dots, lighted scopes etc, flashlights and few oter things too. no leakage issues like I was having with big name bran manufactures I have one other bran too from then that lasts. No idea if it's in flashlight or sight and already get my project for
Today. I hope this helps.
Their are numerous YouTube videos, blogs, websites that show you how to take apart battery, test and replace a single cell or all of em. How to boost power, run time. Also about life expentency etc. some useful tips if you look around. I didn't save any of em either. I looked . Some of info is way to much hype so you have to read though and figure fact from bs on some of em.

 

[Laker]

thanks for the detailed reply Hammertime

 

[eric_koski]

Buying sub-c batteries on line @ 2-3 bucks each plus shipping is going to cost almost as much as buying a new replacement battery. I priced them. Cheapest way is Harbor Freight. I'm a cheap *******. If anyone can find them cheaper please let me know.

 

[Laker]

the replacement battery for my 19.2V Porter Cable circular saw is $90-$140 (PC-1922) and uses ****** sub c's. Batteryjunction.com has them (16) for $25 + shipping. seems like a Charlie Sheen "win" to me

 

[racingtadpole]

but looks stupid dangerous.

That would be because it is... Under NO circumstances should you do this. What happens when the battery loses capacity is that the plates are sulfating up (developing the chyrstals you mentioned). Eventually what happens is the layer of sulfate becomes so thick it joins between the plates and renders the cell useless. When you 'zap' a battery, you have no way of knowing what level of chrystalisation has occured in your batteries. If the plates are completely sulfated up, they will appear to the powersource you are using as pretty much a dead short. Its not beyond the realms that you could cause the battery you are zapping to explode, along with the battery you are using as a power source. IF you are fool hardy enough to use an AC source (such as a cheap welder) to zap the battery then the chances of the battery you are zapping exploding rise exponentially. Welders (and cheap battery chargers for that matter) are crudely regulated, if at all and have the capacity to supply big mobs of amperage. The resulting explosion can be horrific.

I work with large battery banks (2000AH at 2V is considered small at work) in standby power systems and the thing that most people forget is that a battery is a container full of chemicals and the chemicals react to make/store electricity. By altering the chemical reaction (ie zapping batteries, and any other variation on the theme you care to name) you can find yourself amidst some very undesirable consequences.