# Rechargable Batteries



## Jeff May (Nov 16, 2013)

Has anyone ever rebuilt their batteries for the cordless equipment?
I have several 19.2v Craftsman batteries that won't hold a charge anymore.
I recall seeing some info somewhere about doing this, of course, now I can't find it.
Is it worth trying or just bite the bullet and buy new ones?
Thanks,
Jeff in Hagerstown


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## pdentrem (Nov 16, 2013)

One can either replace the cells, there are sellers on the net, or send in for a rebuild. Usually one cell has failed just like in your car battery. If you watch the sales, sometimes it is cheaper to buy new kit but you will still be stuck with needing the old ones rebuilt.
Also check warranty as some of the better marks are longer vs the cheaper ones. 
One advantage in doing a rebuild, one can get better quality cells or even switch out the NiCads and go to Li ions.
Pierre


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## itsme_Bernie (Nov 17, 2013)

I know the guy on ebay, and did two batteries with him.  It is written on the batteries themselves, so I'll check tomorrow and post the info.

The batteries were better than new!

Bernie


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## Hawkeye (Nov 17, 2013)

Keep in mind that, if you change battery types, you have to change chargers. I saw a video once in which they intentionally used the wrong charger on a lithium battery. It soon caught fire. Metal fires are nothing to take lightly.


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## Tony Wells (Nov 17, 2013)

I use a ton of DeWalt cordless tools, and I get my batteries rebuilt at Interstate. Granted, I get a commercial discount but they are quite a bit cheaper than replacements, and superior cells. I believe instructables had a how-to on doing it yourself. They are sub-C cells I believe in most of the packs.


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## furpo (Nov 17, 2013)

This add is on Craigslist all of the time. He quoted me $50 for the Battery for a Fluke One Touch

 Batteries for cordless power tools - $45 (Green Bay, Wi) 
Let the Battery Medic rebuild you NiCad power packs. For about half the cost of a new power pack we can rebuild you dead pack and make it better that the factory pack. For more information email The Battery Medic at info@thebatterymediconline . com or call us at 920-265-1059
 Visit our website: www.thebatterymediconline.com


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## Dunc1 (Nov 17, 2013)

The Ridgid Ni-Cd battery packs I have use an oversize (quick charge) charger & each battery seems to have an electronic circuit inside (observing through the vent grid; have not opened the case).

Is this some sort of smart circuit that does...[what]?
Are all replacement cells alike? Or do I need cells with certain characteristics to mesh with the electronics?


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## genec (Nov 17, 2013)

I had a Milwaukee drill that the batteries went bad they wanted $89.00 for a replacement pack I purchased one, then I took my old battery pack over to interstate batteries and ask them if they could rebuild it, they did for I believe it was $39.00 I am pleased with both of them.


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## Hawkeye (Nov 17, 2013)

Dunc, the wiring you see on the inside of a NiCad pack is for a heat sensor. That is a common way that the chargers use to shut down when the battery is charged. It heats up when full.


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## LEEQ (Nov 17, 2013)

When I have priced cells it was the same as having it done or more. So I would have them done. I would also ditch the craftsman/Ryobi drill in favor of a NiCad dewalt. Lots of people make good tools with cords. DeWalt makes cordless tools worth owning. I like Nicads in that I can use them in the cold, The lithiums I use at work aren't worth a s#$% in the cold. At least a 50% decrease in use between charges. I'm sure lithium will get a little better and flat smoke oldschool batteries, but for now A xrp dewalt is primo. I have run one pack year round for 8 years before needing a replacement. If you invest that money in batteries, you still have a Ryobi made craftsman drill. They feel like toys in comparison. Think about a better drill, you don't have to have a 19.2v around the house. A 14.4v good drill can be had fairly cheap with two packs and a charger. It will outperform the bigger sears one anyway. K I'm done. My two cents and all


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## David S (Nov 17, 2013)

Hi Folks.  Just to save someone from a serious fire, please do not attempt to change standard subC nicd cells with LiIon.  The most common LiIon size cells are so called 18650 (18mm dia, 65mm long) so do not have the same form factor as SubC.  The real danger however is in the battery management system.  This controls the charge as well as the discharge.  LiIon cells should not be over discharged.  While LiIon cells do not contain any free Li metal, they can form free Li metal if they do not have a proper battery management system.  The main issue is fire due to improper charging.  The electrolyte in LiIon cells is flammable, unlike Nicd or Nimh.  Also with over charging and the cell temperature rises, eventually you get thermal runaway and oxygen is generated.  So you have flammable electrolyte, self generated oxygen, making it very difficult to extinguish the fire.

Also having spent 15 years evaluation cells for the major power tool company, I will have to agree that DeWalt nicd cells are the best that are currently produced.

And just a note, if you elect to replace cells in a pack, the new cell connections will have to be spot welded.  Soldering risks damaging the separator or the vent system.

Just want to keep folks safe.  I have witnessed too many fires during abuse testing.

David


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## itsme_Bernie (Nov 17, 2013)

Wow thanks David! 
Great tips- I have wanted to start replacing my cells, and may likely have considered "upgrading" to LiIon.  

I have to ask you though- my chargers are meant for both LiIon and NiCad because they are Ryobi.  They sell LiIon batteries now too, and both types of battery can go in one charger.  D you think that is ok, since the charger is meant for both?  
Unless the battery has some circuitry to tell the charger what type of battery it is...  Hmmm..   


Bernie


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## David S (Nov 17, 2013)

Bernie, I am not familiar with the latest Ryobi packs.  However one of the differences between the battery management system (BMS) is that with LiIon there are usually cell taps off of each cell of the string in order to makes sure that an individual cell in the string is not over charged or under discharged.  Nicds don't have that.

If the charger is designed for both types of chemistry, then it would be ok to replace cells, however again it is more tricky with LiIon since the entire pack should be balanced.  And like I say in order to replace cells then the weld straps have to be spot welded.  If you have a spot welder you can try.

As I read your post, if you are talking about "upgrading" a nicd pack to LiIon, then I would say no you can't do that.  There should be some different connections and perhaps electronics in the LiIon pack that won't be in the nicd.

David


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## Hawkeye (Nov 17, 2013)

Bernie, as mentioned, don't replace the cells in your NiCad packs with Lithium. Check whether the OEM lithium packs will work in your tools. Most tools made for lithium have circuitry to prevent unsafe discharge conditions. The NiCad tools may have different dovetails or contacts to prevent interchanging the battery packs. 

The charger may be the only component that's made for both.


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## pdentrem (Nov 17, 2013)

I needed a new battery and the charger for B&D 14.4v unit. $45 battery & $55 for the charger. Looking around the store I found another kit - drill, saw, light with 2 batteries and a charger for $105. Guess which I bought. The new charger lasted maybe a year. I now use a different charger that is more robust, ie has a fuse, the batteries are not as strong as new and I was thinking of trying out the battery rebuild service that The Source offers locally.
Pierre


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## SEK_22Hornet (Nov 18, 2013)

Can't speak for the Sears stuff, but I have been using the Ryobi for several years and have no problem with it.  One of the things that made me buy it in the first place is the wide choice of batteries and other tools that use the same system - string trimmers, drills, impacts, saws, etc.  NiCd or Li Ion.  Batteries are a lot cheaper to replace as well, especially if you buy two packs.  I am just about fully LI Ion now and love them.  If you are using them around the house, they are just fine.  If you are using them 8 hours a day, consider the Rigid line, since they will replace the batteries for free, if you register the tool and keep a copy of the receipt. Of course those options only work if you have a HD store handy. However, I'm certainly not saying DeWalt is bad....To get back on topic, you can use individual cells, but be sure to buy the kind that have tabs welded on them.  You can pick your price range and capacity if you do rebuild them yourself.  Last time I saw a sears battery price, I beleive it was pretty pricey, so rebuilding might work out well.  I have bought cells from a company called All battery with good results. If you can solder, you can probably rebuild it yourself.  Take a look inside the pack and you will soon know if you want to tackle it yourself or not. As for the temp sensor being used to determine full charge, I believe you find that most chargers use a voltage / charge current curve to detect full charge rather than temperature - using temperature is a good way to ruin a cell in a hurry bu over charging. The temp sensors are usually used as safety devices to prevent overcharging. Oh - and it's not usually a good idea to try to replace one or two cells, as this can cause other cells to over or under charge due to mismatched internal resistance of the old and new cells, since they are charged and discharged in series.

Dan


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## itsme_Bernie (Nov 21, 2013)

Sorry about the late response- VoltmanBatteries.com!!  That's who I used and they were great.  



Bernie


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## itsme_Bernie (Nov 28, 2013)

I haven't used this company, but had their link:

http://www.wcbatteryrebuilders.com


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## davidh (Nov 28, 2013)

in my past business I serviced batterys for my contractor customers.  I even built a battery "tab welder" with couple gawd awful big capacitors, diodes and switches.  most of it fits in a empty computer tower. a fun project to say the least.   actually I still have it.  but it needs about 16VDC and I don't yet have a power supply that will go that high.  two neat little probes and a foot switch to trigger the diode to zap the big capacators.  quite a jolt that could cause serious harm.

I purchased the batterys pac's from a place in calif. that assembled the pac's and I just had to do a smalll amount of connecting when I installed them in the cases.  

interesting idea I had, going into the rebuild business by obtaining the single cells and spot welding them in the proper array. . . cost on batterys was really low if ya wanted to spend a couple grand on batterys, so I abandoned that idea.  but I did find the sources where they were reasonably priced.  

I so realized that I could not compete with "batterys plus" or "interstate battery" without a big advertising campaign which is more than expensive.  

prior to the tab welder I actually soldered the tabs on, using a big copper "club" type soldering iron heating it with a torch.  the club got the part hot REALLY fast so you would not heat the part slowly with a little soldering gun and ruin the battery.  I never had a complaint about that procedure.


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## mattthemuppet2 (Dec 12, 2013)

I've rebuilt a couple of B&D 18V NiCd packs (which are crap) with lithium polymer cells salvaged from dead laptop batteries (I can hear people running screaming for the fire exits now!), which I test for voltage, capacity and self-discharge. Usually one or two parallel pairs has gone bad and tripped the pack PCB and the other pairs are often fine. Some packs are just plain worn out or have been left uncharged for too long, but about 60% of the 60+ packs I've torn down have had a duff pair. 

Anyway, one pack was built 5S2P with ~3Ah cells for ~6Ah total capacity, the other pack was built 5S1P with ~2.5Ah cells. The first to have enough juice and discharge rate to power my strimmer (which'll rip through a NiCd battery in about 10 minutes), the second as a light weight battery for my drill/ vacuum/ palm sander/ hedge trimmer/ circular saw. They're interchangeable, with the exception that the large one won't fit in the vacuum as I had to make a little riser to fit all the cells inside. Both have balance taps wired to a balance plug glued into the housing and I use a voltage monitor to keep an eye on voltage during discharge (as pointed out above, over discharge kills lithium cells). I balance charge them using my RC hobby charger. They're both fantastic - either slightly more capacity and less than 1/2 the weight or over twice the capacity and the same weight as the stock NiCd batteries. They hold their charge for months and work fine below freezing (like last night), plus they hold enough capacity to be able to use them to do trail work - the large battery allowed me to reopen a 2-3mile section of trail with my hedge trimmer all on one charge (almost 3h of continuous use) - without having to lug heavy petrol powered tools into the woods.

However, all of the caveats mentioned above do apply - working with lithium rechargeables, especially unprotected cells, isn't for the foolhardy. They contain an incredible amount of energy which'll more than happily melt metal if you let it and they need extra care with charging. That said, I've found lithium batteries to be very robust and I've used them (mostly bike light batteries) in some very tough conditions without problems. If you're up for investing some money in a good charger (which can charge lots of other things), reading up on how to make packs and handle the cells, then I don't think it's that big a deal.


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## SEK_22Hornet (Dec 12, 2013)

I rebuilt a hand held transceiver battery pack using 3 LI Ion cells and a protection board from ebay (runs around 10.5 to 12 volts).  The board controls charging max voltage, max discharge rate, and low voltage cut-off.  It was less than $6 if i remember and the pack works great! No worries about the cells since it is designed to monitor all cells individually (cells all wire to points on the board).  No special charger required - the board cuts off the charge when the max cell voltage is reached. I still have some cells and are thinking about a Li Ion battery for my olde Ryobi 12 volt drill. Still have a couple boards left


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## DAN_IN_MN (Dec 12, 2013)

SEK_22Hornet said:


> I rebuilt a hand held transceiver battery pack using 3 LI Ion cells and a protection board from ebay (runs around 10.5 to 12 volts).  The board controls charging max voltage, max discharge rate, and low voltage cut-off.  It was less than $6 if i remember and the pack works great! No worries about the cells since it is designed to monitor all cells individually (cells all wire to points on the board).  No special charger required - the board cuts off the charge when the max cell voltage is reached. I still have some cells and are thinking about a Li Ion battery for my olde Ryobi 12 volt drill. Still have a couple boards left



Great post, Dan from Kansas!


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## mattthemuppet2 (Dec 13, 2013)

those PCBs are great, but you have to make sure that all the series cells are very similar (same batch ideally) and at the exact same state of charge when you wire the pack up as they won't balance the cells. They will cut off the pack when it goes too far out of balance though. Balance charging PCBs (which you'll see in li-ion tool packs) are much larger and more expensive.

The 5S PCBs I found (not even balance charging ones) were crazy expensive, otherwise I would have used one along with the balance tap. As it is, some care and attention should be fine.


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