Black & Decker Versapak Upgrade to Li-ion




About: I'm just a mutant ferret.

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

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

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

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.



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    40 Discussions


    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.


    Reply 2 years ago

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


    Reply 1 year ago

    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:



    Reply 1 year ago

    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.


    Reply 1 year ago

    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.

    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.


    4 years ago

    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.

    1 reply

    Reply 4 years ago on Introduction

    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.

    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?

    2 replies

    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


    4 years ago on Introduction

    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.


    5 years ago on Introduction

    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.

    1 reply

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