Introduction: Black & Decker Versapak Upgrade to Li-ion

Picture of Black & Decker Versapak Upgrade to Li-ion

Remember the Versapak from Black & Decker? It's a low voltage compact rechargeable system which is getting hard to find in your local hardware store. They are typically Ni-Cads (nickel cadmium) and the more expensive one uses NiMH (nickel-metal hydride).

Well I wanted to take out the old batteries and install some Lithium-Ion batteries so they would be easy to replace in the future. I decided on a Li-Ion 3.6V 650mAh Rechargeable RCR123A battery. 2 of them in fact. Hooking them up in parallel will equal the original voltage. 3.6 is the original voltage. These batteries will not have the memory problem of the old batteries. You will need a new charger for them because the old one will over charge and you might have a fire. You'll also need 2 battery holders that are the right size for 123A batteries.

Tools you will need:

Dremel tool with cutting wheel
wire cutters
soldering iron
small flat head screwdriver
glue gun
120 grit sandpaper
Duco cement or equivalent

I think that about covers it.

Step 1: Taking the Battery Apart

Picture of Taking the Battery Apart

You will need to take apart the Verapak battery. Start at the end with the black plastic end piece. It is very hard to get off. I used a razor blade to cut a vertical slit to put my small flat head screwdriver in to pry it off. Try not to deform the plastic because we still need it.

It was suggested by easy-does-it to use boiling water to soften the plastic to remove. This idea should work better. Once the plastic starts to get soft I would think you could just pop it off.

Now that you have it off it is time to use the dremel to cut out the end so we can remove the batteries. Don't forget to use your goggles.
Try and cut as close to the edge as possible. There is a rubber washer on the inside at the end and will probably start to smoke once it heats up. You'll see it once you start cutting in deeper. Remove the rubber washer. Once that is done the batteries should fall out. Just tap it on the table and it should come out. The battery that comes out last will have a metal cup spot welded to the positive terminal. Use the screwdriver to pop it off. Don't bend it. We need it. If the screwdriver isn't working, use a putty knife or pocket knife.

Now you can start cutting out a large slot like you see in the picture. Make it wide enough so you can fit the battery holders. Make sure the battery holders are set in deep enough with a battery installed. You don't want the batteries to be sticking out. Be sure and sand all metal edges so you don't end up cutting yourself.

Step 2: Soldering and Assembly

Picture of Soldering and Assembly

Ok, now we get to solder. We are connecting the battery holders in parallel. In other words the negative to negative, positive to positive.

Here is the line up.
The small metal cup is the positive. Solder both positive wires (red) to it. Solder the negative wires (black) to the bottom of the case. The small cup fits in the top of the battery case. I used Duco cement to keep it from moving. You could use super glue as well.

I used a glue gun to keep the battery holders positioned. Before you hot glue anything test it first. Once the hot glue sets, it will be very hard to get to the wires if something is amiss. If it isn't working check your soldering connections. Is the battery charged?

A little hot glue will also hold in the black plastic end cap.

Step 3: Done

Picture of Done
That should do it. Easy huh?

Now you have batteries that you can easily replace and for a much lower cost. It also is lighter. It weighs less than half the original.


The down sides are that it may not last as long on a charge as a new one from Black & Decker. So far so good. I've used it on 5 jobs and haven't needed a charge. My old battery would have died on the 2nd job.

(edit: I have found that it lasts about as long as the original battery)

I got the battery holder, Li-ion batteries and charger at

Thanks for reading my first Instructable.

Update: 01/24/12

It still works. I am still using the same battery. I have dropped it several times and only one time did I have to bend one of the battery connectors back into place. Since this mod is lighter than the original it doesn't fall out near as often. The red clip ring thing  isn't such a good design. It currently stays on the workbench and will only see light duty work anyway.


lolzertank (author)2009-07-03

Why don't you use a single 18650? You'll get about 2x more capacity than the 2 RCR123s combined.

mutantferret (author)lolzertank2009-07-20

Yes you are correct and you could easily use that type of battery. I just chose differently because I already use them for other things.

JenieL2 (author)mutantferret2017-04-25

What type of charger should be used with the 18650 batteries?

mutantferret (author)JenieL22017-04-28

This looks like a good one.

You need a charger that is specifically designed for it. Much more affordable today than just a few years ago.

MichealK10 (author)mutantferret2018-01-11

I can vouch for EBL's, they are about the best budget 18650 I've seen. Be careful and avoid UltraFire and other knockoffs.. biggest info to avoid fakes is the max current they hold is 3.4Ah (and that's best, ones that are rated at "9800mAh" have been tested to perform 10% that... they are crap). I digress. I'd personally recommend these:


mutantferret (author)MichealK102018-01-15

Thanks for the info and the links!

amclaussen (author)JenieL22017-11-23

Although there are some small chargers that can recharge a canned Lithium cell, the charger needs to be specifically designed to recharge a LITHIUM cell... It is dangerous to try to recharge a Lithium rechargeable cell with any other type of charger! the risk is from severely bulging the cell, to exploding and catching fire. I use a very versatile charger that is sold to recharge the multiple cell types used in Aeromodeling, as you need to recharge the NiCad or NiMH cells in the transmitter (usually 8 AA cells pack), or the Receiver (usually a 4 to 5 cell pack of variable capacity) or the Lithium Ion cells like the 18650, or Lithium Polymer cells like those for electric model airplanes or Helis, and even Lead-Acid small batteries. I use and recommend the "Triton" charger or any other of the ones used for RC model airplanes because of its versatility, the protection circuit it has and the convenience.. Amclaussen.

amclaussen (author)lolzertank2017-11-22

Very good suggestion, not only the capacity is much higher, but even more important: the internal resistance is much lower than half the resistance fo the RCR123 (paralleling two of them halves the resistance, but the single 18650 cell is even better). In motorized applications, the current demand governs the performance, thus the lowest cell internal resistance, the more actual power the device can utilize. Years ago I was quite ignorant about battery performance, I went to a wedding, where one of the friends of the bride was performing as the Unofficial-official Photographer of the ceremony. I saw him loading 4 AA cells of the rechargeable type (those were the older NiCads)... I naively pretended to know about electronics and said: "Maybe you are losing the speed of recharging your camera's flash, because those rechargeable cell are ONLY 1.2Volts, so those would be SLOWER to recharge the capacitor in your photo flash and you could lose some important moments in the ceremony". HA HA, he answered, and asked me to see how SLOW were a completely new set of 4 AA Duracell Alkaline batteries he had at hand... HE loaded the Duracells rated at 1.5V, but that measured 1.605 V with a digital multimeter, versus his Radio Shack garden variety NiCads. IT was a no-contest, as the NiCads were MUCH, MUCH FASTER that the new Duracells, so I had to publicly admit I was completely wrong! Some time later, I learned that the NiCad, even at less than half the charge, is faster to recycle the Flash because under the heavy current demand of the Flash, their lower internal resistance provide much faster recycling times.

richard.fisher.5473894 (author)2015-01-16

I should mention, the screwdriver does a slight turn, more of a bump and that is all. With Versapak battery it works fine.

When a battery can only supply a very brief burst of power, it means that battery has a very high internal resistance (because it has degraded too much) or because of a "protection circuit" impedes it to supply a larger current. Check your battery's output current capability. Look at webpages on rechargeable batteries for testing methods. A good 18650 cell is capable of turning a small cordless drill much better than the NiMH or old Nicads, but you need to match the batt pack voltage to the requirement of the drill. I replaced the ailing Versapack batteries in my old Black&Decker cordless drill that uses two Versapacks (7.2 volts NiMH by installing three (yes 3) Lithium 18650 cells because the motor is strong enough to handle the raised voltage quite well. This weak model of drill now has better power and the charge lasts more then when it had new NiMH Versapack batteries.

I recharge the three 18650 batteries with my Aeromodeling charger, called "Triton" that can recharge either NiCads, NiMHs, Lithium-ion and LiPo (Lithium-Polymer) cells as well as Lead-Acid batteries, because it was sold for aeromodellers that use 8 cell Nickel packs in the Transmitter, 4 or 5 Nickel cells in the Receiver, and LiPo cells in electric model airplanes or Helicopters, and the 12 volt Glow plug engine starters. All in all a VERY VERSATILE charger! Amclaussen.

russ_hensel (author)2015-02-05

Just a note to let you know I have added this to the collection: Cordless-Drill-Battery-Maintenance !


Take a look at a bunch of different/similar approaches to this project.

mutantferret (author)russ_hensel2015-02-07

I like what you've done. Thanks.

obod0002 (author)2014-07-22

Thanks for your excellent work, mutantferret.

Does anyone know if I could use the old B&D charger when I choose a 18650 battery with overcharge protection circuit included?

Don't want to risk a fire ... but keeping the DIY bit to a minimum.

mutantferret (author)obod00022015-02-07

Thank you. To answer your question. I just wouldn't risk it. Use a
charger that specifically charges the kind of battery you are using.

richard.fisher.5473894 (author)2015-01-16

I have tried this with 18650 that is 5000mah with circuit protection however, it is not turning over the cordless screwdriver. Can someone confirm that the 18650 will indeed work?

There aren't any legitimate 18650's that are 5000mah - the most advanced are only 3400mah - have you tested the battery by itself?

The batteries were good however, what I discovered was that the circuit protection was keeping it from working. I switched to Panasonic 18650 unprotected with high output rate, and it works great.

Panasonic NCR18650PF 2900mah

zebra9780 (author)2014-12-05

to be careful that Li used have different charger then NiCd or NiHm, and most Ni-charger is not good use for LiOn, you may use charger that for mobile phone ( normally is 3.6V) to charge your 18650. ( just need a longer time)

In additional, use on Tools, the Li battery most have "protector" to avoid over discharge, which is happend when you drill on hard or drive on higher tongue. otherwise Li battery easy over heat (fire or explore) by high current output.

Armadillo123 (author)2014-05-26

Photo for easy visualization. The original battery seems like custom made. It is non standard sizes measuring 21.9mm X 31.8mm each. The marking on it is "GL07ME". Any batteries expert can advice on this type of batteries would be appreciated. I suppose this near 4/5 sub C battery gives a few punch on amperes draw. Some recommended 18650 Li-ion battery dimension seems a bit short and thin because it only measures 18mm X 65 mm.

Good photo. It probably is a sub c type. I have found that dimensions vary from different manufacturers. Same for lithium cells.

I found this battery 21mm X 32mm at 2500 mAh, the size fits nicely. The objective is to slot in the batteries the way it has been taken out and then cap is back with the black plastic cap, As good as new. You do need to spot weld the batteries though. Note: Different manufacturer makes 4/5 Sub-C battery differently, the size is not the same. You can buy from ebay, 4 pieces about US$8.00. With that, you are self-assured of the mAh battery you have. :-)

RodCastler (author)2013-07-22

Thank you for helping me giving a new life to my old screwdriver!

I was able to stick in a laptop cell inside the Versapak can.

a) Hot water allows you to easily remove the plastic cap. No need to boil, just hot.

b) I soldered the metal cap to + terminal of the battery using a small torch (first add solder to the positive terminal of the battery and the small metal cap with your favorite soldering iron, and then heat up the metal cap so they stick together for good.

c) Solder a cable to the negative terminal of the battery and slide the battery inside the can while matching the metal terminal to the hole with the help of a screwdriver for correct alignment. Then heat up the back of the can with a torch to solder the other extent of the wire to the inside of the can.

d) fill the remaining space with paper to prevent the battery from moving loose inside the can.

Replace the plastic cap and you're done.

mutantferret (author)RodCastler2014-05-30


abreuma (author)2013-04-15

Nice instructable. Just ordered some battery parts to try this. Can I assume I'm cutting the end of the case off from the side of the case rather than the end of the case? I assume the batteries are so large that cutting the end won't provide a hole large enough for the old batteries to fall out? I would have loved to have seen a photo of the end you cut while looking at the end of the battery.

mutantferret (author)abreuma2013-05-19

Yes just cut the end right off at the bottom of the battery, not the side, and they slide right out. I'm sorry I didn't take a photo of the end. Guess I should have. Hope you have success.

jonrhynard (author)2011-12-10

For the batteries and charger - dealextreme seems to have better prices:

mutantferret (author)jonrhynard2011-12-22

Hey thanks. I would definitely use 18650's if I were doing it all over again but I have quite a few RCR 123a batteries. DealExtreme is a great place to buy.

yoog (author)2010-09-22

"I got the battery holder, Li-ion batteries and charger at "

Do you have part numbers for them so I can order from them?
Very nice write up.

mutantferret (author)yoog2010-10-12

Sorry it took so long to write. You may do better to use a different battery such as a 18650 Lithium suggested by lolzertank.
Here is the part numbers you requested at :
Part Number: RCR123A36 - battery
Part Number: CH-RCR123A36 - charger

Or you can get 4 batteries and a charger with this
Part Number: CH-RCR123A36C01

Hope that is what you need. You probably built it already buy now LOL

Gee, I can't spell. I meant by not buy

easy-does-it (author)2010-02-05

The plastic end-caps can be removed quite easily by first soaking the end of the cell in boiling water for 15-30 seconds.  It is advisable to hold the cell upright so that the "working end" remains out of the water (the plastic end is sealed, so don't worry about damage).  The caps then come off surprisingly easy!

Secondly, I have used recovered laptop cells to rebuild these versapak units.  The cells used in most laptops are very probably the 18650 units that were mentioned above.  The versapaks that I have rebuild with discarded laptop cells have lasted two years (upto this point - we'll see how much longer). Cheers!

cmdrdata (author)easy-does-it2011-02-02

I have several bad Versapaks and I decided to use a used battery from my old laptop powerpack (they are 18650s). Here's what I did.

1. Remove the cap in hot water as easy-does-it recomended. worked great.
2. Cut off the end of the Versapak using a Dremel tool. The entire bad NiCd assembly can now be pulled out.
3. Remove the positive "cap" from the off battery.
4. Carefully remove the metal strips connecting the 3 NiCds you'll need two to be re-used.
5. Solder one of these metal strip to the cap (step3) and pushed back into the cavity of the battery pack case. This will be your positive terminal for the screw driver.
6. solder the other strip to the back of your salvaged 18650 Li_ion battery so that it sticks out about 1/4 inch or more.
7. At the cut off end of the Versapak case, make 4 marks with a marker, and using your Dremel cut two quarter sections of the metal from the cut end to the "groove" of the metal case. This is for the cap to go back in later where you can remove it for charging the Li_ion off the container.
8. Using a Dremel with a burr bit, trim off the raised groove in the inside of the plastic cap that was on the Versapak at two of the quarter positions. The idea is that so you can slip this into the Versapak case, twist a quarter turn and you're now locked.
9. Put the Li_Ion battery into the case, making sure the back/negative tab sticks out and touch the metal case inside the hole. Cut a slightly larger faom rubber to keep the battery snug from the back, and put the trimmed plastic cap back on. You now have a Li-Ion Versapak.
10. To recharge the battery, just untwist the back cover, and place your 18650 in a universal charger. I'll send you a picture later if you want.

easy1 (author)easy-does-it2010-12-11

Very nice idea, 'easy-does-it'!
I made it with your boiling water instruction, the cap went off very easily! :-)
But now I don't know how to get further.
This is my "status quo" (higher resolution under )

easy-does-it (author)easy12010-12-17

easy-does-it says:
easy1: Sorry for delayed response but just received your post today.
The secret is to "cut" off the end of the metal Versapak battery cylinder (seen in your top photo). I was very careful with my first one but found that there is sufficient material that you don't have to treat this step as critical. The object is to remove just enough material from the end of the Versapak cylinder so that the old Ni-Cad cells contained inside can be slid out. I used a Dremel parting-disk, but an electric grinder (used with reasonable care) works just fine. With the cylinder opened in this manner, the old Ni-Cad cells (3 of them) easily slide out. They are wrapped in a cardboard tube. I remove the cardboard tube and re-insert it back into the metal cylinder.

I then obtain my new Li-ion replacement cell and "adjust" its diameter to snugly fit in the cardboard-lined Versapak cylinder by wrapping about three layers of black electrical tape around the new cell. I then remove the positive center button from the old cells and solder it to the positive terminal of the new cell. Next, to the negative end of the new cell, I solder about 1 inch of copper braid (I think that 18 or 20 gauge stranded copper wire would work as well). I then insert the new cell, positive end first, into the Versapak cylinder and solder the end of the copper braid to the inside surface of the Versapak cylinder.

Now to "re-close" the cylinder I obtain a neoprene rubber cork (I found them at the local ACE hardware) which have the exact diameter as the Versapak cylinder. I depress the cork into the cylinder until it makes positive contact with the Li-ion cell. This step insures that there is sufficient "spring" pressure to maintain electrical contact between the positive button of the Li-ion cell and the connection to the tool in which it is used. I then drop the original "rubber" Versapak cap into boiling water for about 30 sec, then fit it back onto the newly restored cell.

Hopes this helps. The next time I restore a Versapak battery, I will take some photos and post them.

Also FYI, a short time age a fellow wrote an article in SERVO magazine describing a circuit which converts an original Versapak charger into a "smart charger" for NiMh cells. I believe the kit is presently available on eBay. Since this "kit" is designed for NiMh cells, it is not suitable for Li-ion or Li-Po cells. Maybe I will author an Instructable illustrating how to modify a Versapak charger so that it can be used to safety "smart" charge Lithium-based cells.

easy1 (author)easy-does-it2010-12-17

First of all I have to mention that I'm German, so please don't matter about my bad English and my grammar. :-)
By the way, if you shouldn't know (but I guess you know already) the online service area of 'Black&Decker' regarding details about the 'Versapak' products, where you can find some manuals, spare parts and repairing drawings of the most tools, is here:

Many thanks for the hint regarding the SERVO article that I've read completely, but in my opinion this loader-pimping is a very expensive method, moreover it's not able to load the Li-batteries, as you said.
A "neoprene rubber cork" is the same as a cork for wine, e.g. these ones, isn't it?

I've read the updated version of your comment. So that means you primarily had been talking about the replacement with a single lithium battery?
Lithium would be very nice, according to more power of the B&D tools (do they really become more "aggressive" with Li-batteries in comparison to NiCd/NiMh?).
In Germany I could get a new Li-loader for about 25$ and easily connect it to the inner contacts of the original B&D loader (just completely bypassing the existing electronic), it would lie beside of the B&D loader.
In a sense I would be interested in the 'vp110'-batteries (= Versapak Gold NiMh), but it's simply not possible to get them in Europe, and (cheapest deal) doesn't ship them to Germany.
But which ones would bring more power (not endurance)?

Actually I had one original and untouched VP100 battery only which was totally broke down -> I did the "youtube"-hint and connected plus/minus of the VP100 vice versa with the poles of a 9,6V battery for 8 seconds periodically, let it rest for 15 minutes and loaded it for 20 hours in the VP120-loader. Incredible, it's as powerful as a new one now.
In addition I bought a new "Xcell" 3,6V NiCd battery (china ware, but pretty solid) for about 10$ one weak ago.
So today I've tested all my recently purchased VP-tools (really a lot, all in used condition) and I'm very satisfied and absolutely surprised! Couldn't find better tools for light duty/rarely operation at this ridiculous price (ebay).
Great thing, convinced! :-)
But a "little" more power for the circular saw (VP600) and the leaf blower (VP4300) would be very nice, maybe with NiMh or Li?

easy-does-it (author)easy12010-12-17

Hi easy1:

Sounds as if you have a good understanding of the important factors in this subject. I don't know if I can add much more info.

That is an excellent idea to just connect the ouput of a "smart" NiCad charger, or a "smart Li-ion charger, or a "smart" NiMh charger to the terminals of a Versapk charger (bypassing the original Blac&Decker circuitry). This is an easy way to convert the original ?dumb? charger into a useful one that does a good job with the battery of your choice. If one were to modify the original charger to just connect the battery terminals to an electrical jack, then it could be used for any type of original or modified Versapak battery by just pluging in an appropriate charger.

My opinion on the performance of the Black&Decker tools when powered by different types of batteries is that you will not see much difference at all in the "aggressive" output. This sort of depends on the voltage output pf the battery. The three popular choices of NiMh, NiCad and Li all discharge at about 3.6V over most of their discharge cycle. Also, the three types have (within reason) the same capacities (about 1200 to 2200 mAh). (Of course, the higher capacities will run the tool for a longer period.) And the price is about the same for any of the three if you buy OEM cells to rebuild the Verapaks. NiCad cost about $2.00 USD for 4/5 sub-c 1200 mAh, so that is $6.00 for per rebuilt Versapak. The Li 18650 cells sell for about $8.00 USD for 1800 mAh to about $12.00 for 2400 mAh. And the NiMh sell for $4.00 per cell for 3600 mAh which equals about $12.00 to rebuild a Versapak.

In your case, if you are interested in the B&D Gold-Pack, the way to go might to be buy the high capacity NiMh cells. I think you would have about three times the electric capacity over the B&D version of the GoldPack, but see my comment above about performance (versus endurance).

Everyone who uses NiCad batteries as a staple should pay close attention to your "rejuvenation" comment. I been doing that techenique for 20+ years with great success. Over 90% of "dead" NiCad cells will show good response to the treatment, and most of those will perform "like-new" for a long time after.

And finally, I think that a wine cork would work just fine. The ones I used are traditionally shaped tapered ones usually used in laboratories to stopper flasks.

Very clever. I didn't think about boiling water to remove. Good idea. I have added that tip and credited you in my little instructable. I like it and thankyou for the tip.
Recovering batteries from laptops can be a good idea provided you know how to safely charge them. If they are 18650 then you can pick up a charger for them.

easy1 (author)2010-12-15

Thanks a lot! I will reply on Friday....

wmgupton (author)2009-05-21

Thanks. Nice description on the process. "You will need a new charger for them because the old one will over charge and you might have a fire." What charger did you go with to replace the VersaPak charger? Why would the old one overcharge? "You'll also need 2 battery holders that are the right size for 123A batteries." I assume that the two battery holders are to hook up the new 123As in parallel. What type of battery holders did you use?

mutantferret (author)wmgupton2009-07-20

The original charger has no electronic smarts when charging so it will overcharge your replacement battery, the rcr123a's. I got the new charger at I also got the battery holder at the same place and they are very cheap and cheaply made. I actually broke one on this project so by a couple extra.

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