# Fixing cordless tool batteries



## epson (Jul 28, 2010)

For me I purchased the rigid line of cordless drills because the batteries are guaranteed for life so I wouldn’t have that problem. I already replaced two sets of batteries which I had for about 9 years and finally died. I just called them up, gave them my serial #’s was given a reference # and a place to drop off and pick up new batteries no questions asked. Note, in order for this to work you have to call and register your new tools/batteries or else you will have problems.


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## ratherbefishin' (Jun 16, 2007)

miamicuse said:


> I have a few 12v Dewalt Nicad batteries that are no longer taking charge.
> 
> I found on ebay they sell instructions on how to EASILY fix these batteries.
> 
> ...


Save your money, that info has been around for years for free. I can't believe scammers are still trying to sell it.

http://ysuusy.com/easybatteryfix.html

It's a temporary fix that will give you a little more life if the battery isn't too bad. Don't expect it to be like new, though. You can get full voltage, but your Ah will be lower.
Shops don't "restore" batteries, they rebuild them. The good ones use quality, higher Ah rated cells and you end up with better than original.


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## ddawg16 (Aug 15, 2011)

I'm sort of an expert on NiCads (I used to design test equipment to test new batteries).

When a NiCad is reaching the end of it's life, what has basically happened is that the surface of the coil inside is getting coated with an oxide. Except for the occasional short between plates, all those trick do little to get any real life out of a battery.

NiCad's have a basic life of between 300 and 1000 cycles....and/or about 10 years. Even if you don't use a NiCad much...it still ages....

On some of those battery packs, maybe only one battery is bad....if you have a soldering iron and a replacement battery....you can remove the bad one and put in a good one....

Some advice on getting the most life out of your batteries.

1. Run them down until basically dead.
2. Fully charge but don't leave them on the charger...that reduces the life.
3. Try to avoid letting them get too cold...NiCad's don't like cold
5. Write the purchase date on the battery along with a #. 
6. If you don't use a batter for awhile....on some chargers, putting a battery in it with out it plugged in will discharge the battery. Do that...then fully charge it.
7. Avoid re-charging a half discharged battery.


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## PaliBob (Jun 11, 2008)

There is a video going around that claims to *Only* help Ni-Cads


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## woodworkbykirk (Sep 25, 2011)

just buy new batteries or replace the tool all together


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## BigJim (Sep 2, 2008)

I think you can get the little batteries inside the tool battery at Radio Shack and rework them yourself for a lot less. I haven't tried this but I can see how it would work.


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## jeffsw6 (Oct 28, 2012)

ddawg16 said:


> Some advice on getting the most life out of your batteries.


Isn't this the reason why the chargers, or in some cases the batteries, have fancy electronics and things like "maintenance modes?" My understanding is if you just put them in the charger, the charger will do the right thing?

I have DeWalt 18V XRP and am about to pick up some 20V MAX. I assume the "20V" technology is newer and better, and since I need a couple of new tools anyway, I figure it is a good time to make the change. My 18V batteries have really lasted a long time. The first set I got in ~2000 and I replaced them only once. All I do is put them on the charger when I am through using them for the day.


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## woodworkbykirk (Sep 25, 2011)

the problem with doing this is you seriously run the risk of frying the tool if you dont do it correct.. finehomebuilding magazine did an article on just this topic a few years ago.


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## ddawg16 (Aug 15, 2011)

jeffsw6 said:


> Isn't this the reason why the chargers, or in some cases the batteries, have fancy electronics and things like "maintenance modes?" My understanding is if you just put them in the charger, the charger will do the right thing?
> 
> I have DeWalt 18V XRP and am about to pick up some 20V MAX. I assume the "20V" technology is newer and better, and since I need a couple of new tools anyway, I figure it is a good time to make the change. My 18V batteries have really lasted a long time. The first set I got in ~2000 and I replaced them only once. All I do is put them on the charger when I am through using them for the day.


Jeff....chances are anything new will be Li. Whole different animal....I looked at the physical/electrical characteristics a while back....they way you charge/maintain them is different from NiCad.

For NiCad chargers.....a majority of them (newer ones) use the smart charge feature....basically, if it fully charges a dead battery in an hour or less and has a 'charged' light, then it uses the 'smarter' technology. Typically it uses a pulsed input charge. This helps to break down the oxide that developes on the plates and reduces the heat up of the battery. In most cases, the battery is considered charged when the temp suddenly rises and/or current going into the battery drops below a certain amount. Temp is the more common method. When a battery is fully charged, since the electrolyt can't hold any more electrons, the engery going in is disapated as heat. That is why some chargers will show a battery as charged if you have just finished using it in a high current task and it's real warm. It won't charge until it cools down.


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## BigJim (Sep 2, 2008)

woodworkbykirk said:


> the problem with doing this is you seriously run the risk of frying the tool if you dont do it correct.. finehomebuilding magazine did an article on just this topic a few years ago.


You are right, I didn't think about someone getting the wrong batteries, that would be a double whammy, both battery and tool shot.


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## PaliBob (Jun 11, 2008)

There has been some excellent points brought up on cordless tool batteries
In this thread, let me add a few.
On Battery Replacement:
For Ni-Cads (New tools are still being sold with Ni-Cad Batteries)
Rather than buying new battery packs check out these prices:
http://www.batteriesplus.com/t-storeloc.aspx

Are DeWalt 20V Max Batteries a higher voltage than 18V?
Answer; NO, DeWalt's purpose was ostensibly was just to identify
the new slide on battery pack from the original 18V plug-in battery.
https://enr.construction.com/produc...ordlesstoolswithnew20vmaxlithiumionlineup.asp

Bosch also now uses the *Max* Name on 12V Tools
Three years ago when I first bought a ¼” Bosch Driver the
Li-Ion battery was rated at 10.8 V. Last year I got a Bosch 
¼” Bosch Impact Driver, same size battery but now instead 
of 10.8 V it is called 12V Max
 *Explanation* on why
.


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## ddawg16 (Aug 15, 2011)

PaliBob said:


> There has been some excellent points brought up on cordless tool batteries
> let me add a few.
> On Battery Replacement:
> For Ni-Cads (New tools are still being sold with Ni-Cad Batteries)
> ...


It must be the 'fully charged' vs 'normal charge'.

A typical NiCad will measure around 1.4 Vdc when fully charged. During the typical discharge, the voltage will drop down to around 1.2 Vdc....once you get below about 1.1v.....the battery is pretty much done....after that the voltage drops off quick.

Nice thing about NiCad's is that they have a pretty flat discharge curve.

Here is an interersting read on Li-ion...

http://en.wikipedia.org/wiki/Lithium-ion_battery



> Chemistry, performance, cost, and safety characteristics vary across LIB types. Handheld electronics mostly use LIBs based on lithium cobalt oxide (LCO), which offers high energy density, but have well-known safety concerns, especially when damaged. Lithium iron phosphate (LFP), lithium manganese oxide (LMO) and lithium nickel manganese cobalt oxide (NMC) offer lower energy density, but longer lives and inherent safety. These chemistries are being widely used for electric tools, medical equipment and other roles. NMC in particular is a leading contender for automotive applications. Lithium nickel cobalt aluminum oxide (NCA) and lithium titanate (LTO) are specialty designs aimed at particular niche roles.


and of real interest...



> Avoid deep discharge (depletion) and instead charge more often between uses. The smaller the depth of discharge, the longer the battery will last.[104][_unreliable source?_] [105]
> Avoid storing the battery in full discharged state. As the battery will self-discharge over time, its voltage will gradually lower, and when it is depleted below the low-voltage threshold (2.4 to 2.9 V/cell, depending on chemistry) it cannot be charged anymore because the protection circuit (a type of electronic fuse) disables it.[104][_unreliable source?_] It is frequently recommended to store batteries at 40% charge level.[106]
> The rate of degradation of Lithium-ion batteries is strongly temperature-dependent; they degrade much faster if stored or used at higher temperatures and may even be stored in a refrigerator.[104][_unreliable source?_][107][108]


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## PaliBob (Jun 11, 2008)

This is really Off Topic, but today I got an Ad
for a really hot deal on a Bosch Combo Kit

(+ additional *$25* off at checkout}


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## ddawg16 (Aug 15, 2011)

PaliBob said:


> This is really Off Topic, but today I got an Ad
> for a really hot deal on a Bosch Combo Kit
> 
> (+ additional *$25* off at checkout}


That is a good deal....only problem is that it's 12v.....I'm an 18v guy.....


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## PaliBob (Jun 11, 2008)

Yeah, It's crazy but I just bought the Combo set for $133 with shipping.
Crazy because I already have both tools, although they are older less
compact models. I'll give the old set to my helper


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## JWilliams (Sep 22, 2010)

Well that's mighty nice of you Bob! :thumbsup:


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## Thurman (Feb 9, 2009)

I'll post this one more time, because I have "been there-done this". I own nine (9) DeWalt 18vXP Ni-Cad batteries that I use in my business. I got tired of buying those expensive batteries years ago and then found this: FIRST: _*I am not affiliated with this company*_, just a very happy repeat customer. I found a company by the name of "PrimeCell", I believe they are in Pennsylvania, they have a website. I have sent batteries to them for rebuild and I will tell anyone _from hands-on experience_ that the batteries they ship me are stronger, and last longer between charges then the original DeWalt's. I believe from a, feeble memory, that a new 18vDC DeWalt XP battery has 1200mAH of power. The rebuilt batteries have 2400mAH of power. This is like comparing two car batteries, one with 600 cranking amps and the other with 1200 cranking amps. I believe the last batteries I sent to them were "rebuilt/exchanged" at a price of $46.00 or so. That was over a year ago though, still cheaper than a new 18vXP. There may be other companies out there which do this, but this one is the closest to me.


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## DannyT (Mar 23, 2011)

you can open the battery, take the cells apart and replace them. usually only one or two are bad but the cells can be bought between 3-7 dollars each depending on what you have. search for the number that is on the side of the cell. my son has rebuilt may batteries.


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