Instructables

Mod a cordless power tool battery to run with wall current

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NOTE: I wrote this 'ible before I had a comprehensive understanding of electronics. This is a rather bad idea and will most likely wreck your battery. It seemed intelligent at the time. Oh well, live and learn.

Adding a jack to the battery of a cordless tool so you can run it off of wall current and keep it close to full power all the time. This might not be the brightest idea to do with NiCd batteries, but if you have a skunked battery you can't lose much.

I decided to do this project with the Black & Decker Firestorm 18V system, but you could do it with nearly any cordless tool set.

Things you'll need:
-Cordless battery and charging unit
-Soldering iron and solder
-Wire strippers
-Electrical Tape
-Something to dismantle your battery (In this case Hex wrenches and Torx bits)
-Two wire quick-disconnects (they usually come in male-female pairs)
-Power drill and bit
-Knife or x-acto

You may also want:
-Hot glue gun or epoxy
-Clamps
 
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Step 1: Dismantle your battery

Warnings!:
-This will void every sort of warranty you could hope to have. Proceed at your own risk
-Discharge your battery before working on it. This should be a no-brainer

Each battery is made differently, so I can't give specific instructions on how to take it apart. Mine involved really annoying hex screws that refused to budge. Then I realized they were Torx - hey this is a learning experience. So I got a Torx10 bit and took it apart.

You should be left with two halves of a case, the cells, and possibly some springy do dads.
adasma2 years ago
Just wanna know the rating of the cube power supply, i.e. volts, amps and how much wattage it can handle.
Tnx.
kaos42_ze7 years ago
I have a 100W ( H4 bulb ) portable Flash Lights that has a 12V Lead Battery and it takes ages to charge ( 20+ hours ) and i would like to find a power drill battery that has a big capacity and takes quicker to recharge and mod it to fit in the butt of the flash light where the old battery is now. Most power drill batteries that i seen have 3 or 4 connectors, how do i know what one to use ? I do not want to damage the battery. Also ... can I step up to a 18v / 24v / 36v battery or can that burn the bulb ?
DeusXMachina (author)  kaos42_ze6 years ago
You'll need a voltmeter to figure out what each of the different leads are. I wouldn't use a larger voltage battery, you might get away with 18V without burning it out instantly, but you'll definitely shorten the life. Have you thought about re-celling the lead acid battery? You could hollow out the battery case (wear gloves! the acid isn't too bad but the lead will get right into your system) and put in NiCd rechargables.
great article. i'm curious about the "wall outlet doesn't have enough power." Can you say more about that? i have a computer that uses 90 watts and runs off a wall outlet (dell latitude). it seems we should be able to get around that limitation. thanks, nice article.
helucas3 years ago
Good job man!
sam28v3 years ago
How many m/a transformer do you need for 14 V or 18 V ?

How do you caculate this ?
catnip4all4 years ago
The adapter will spend most of its time charging the batteries, there isn't much useful power from the adapter to run the drill. But you can do it the right way. I've run power drills at maximum speed on just about an Amp of power alone successfully. No batteries, no pollution. 
No pollution? Except for the heavily polluting power plant on the other end :p
You can use solar panels, windmills, or other renewable energy producers to power your drill directly. If we want it, power plants can be made into non polluting ones.
Totally - I'm all for that :p

But that's not the dirty facts on the ground. >75% of power produced in the US is fossil fuel driven :/
trebuchet037 years ago
It's also important that you select a wall adapter that meets your amperage requirements. You want to have at least what your drill will pull.
This is very true. If you are going to be drilling into hard wood or concrete, you will be putting a large load on the drill. If you are using the drill in hammer mode, it will be even higher. A silly 1 amp wall wart from wal-mart won't cut it, you will need maybe 3 or 4 amps... At this point, i recommend buying a corded drill.
I have drilled into concrete, thick steel and everything with just an Amp of supply. Make us wonder why we need polluting batteries.
if you left the battery intact, it will pull the power from the battery, along with the wall-wart, but for that, you'll need a diode
oops sorry admins pls dont delete this i accidentally flagged it
good point
expidition4 years ago
thank great instructable
vlotti5 years ago
Same problem here, I wanted to use my battery power drill, mostly for driving screws in wood. Dead battery after some 2 years, drill still OK, has real low gear and lots of torque. Because the large current none of my smaller electronic power supplies would work, till I remembered a few older, standard PC supplies still lying around, that typically have 12 volt at 10 or more amps. I gutted a battery pack, connected a 12 ft. cord of about 14 gauge strength and in my workshop I can do all the screwing I want. Even so sometimes when the drill stalls, the power supply turns off, but will reset after switch off and on again. Some PC supplies need a little load at the 5 volt, to surely start up, I connected a small bulb of 6 v 1 amp to the 5 volt. This works best with the older XT or AT power supply, the newer ones, ATX, need a signal from the mainboard, which also can be arranged of course... One time I had some heavy work outside, miles from any outlet, to assemble a wooden swing-gate, there I used a few croc-clamps and my car battery, worked fine! tokkoh
andyli6 years ago
That is a great bran-new idea.This is andy from China, we are a replacement cordless power tool batteries manufacturer. Wish can communicate with you all about cordless tool batteries. Thanks and nice day!Guys.
What I tend to do with old cordless drills is to stick on one of those cigarette lighter plug and cord things from an old car vacuum or jacklight. You might want to substitute a heavier cord, if you think your drill will draw a lot of power. Way handy for drilling and screwing in the car or truck. One could also strap a couple of gel cells (possibly from neighbour kid's Power Wheels) to your utility belt, wire them in series to a ciggy outlet, and power your drill with that. Would look real badass with a coiled cord.
ohh, nice. just 1 kink is that it looks a bit odd (plug sticking out the side)
DeusXMachina (author) 7 years ago
See, that's the beauty of it. I found an instructable to mod a cordless drill with wall outlets, and I think he needed three wall warts in order to reach the current. The wall wart provides the first fraction while the battery takes up the slack when you need it. For most drilling purposes, I don't need full throttle, so in situations like those, perhaps 95% is pulled from the wall wart.
ironsmiter7 years ago
sorta fun looking, but i prefer using old, dead batteries for the "ac-adapter" Empty the battery of all the guts except for the contacts, and tie the wall adapter straight to them. now, when you want to run battery powered, use your good battery, when you're near a wall, or the battery is charging, swap to your "ac-pack" and just keep going. My drill/light/saw set are 12Volt, so it was simple to make a powersupply for the heavy draw.120 to 12V stepdown converter from an old laser printer, so very heavy duty. REctify 12V AC to 12V DC. Added 2 capacitors to smooth the ripple, and put in a project box :-)
Thats a good idea. Great instructable.
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