Simple 12V Cordless Drill Hack!!!!!





Introduction: Simple 12V Cordless Drill Hack!!!!!

About: I like electronics.

Give your 12V battery drill some real GRUNT!!!!!

YAY! Almost finished my scooter for Project: Underglow. (Will be published soon) I just need to drill a hole here...(grabs battery drill, clips in battery)...5mm bit......about there......and drill. Bugger. Battery flat. AGAIN. I was fed up. It was 2:30 in the morning. So I did this real quick hack to my drill. AND took photos :) just to show you'se mob.

It basically involves tapping into the 12V input to the speed controller, which would normally be fed by the crappy battery they give you. Sure, you can re-pack them with some big Ni-MH's, but I'm poor at the moment (around A$95 to repack a pack here in oz). So I decided to just hook it to a big SLA, which will give me some juicy current.

*Drill for longer (higher capacity battery)
*more torque (SLA has higher surge current capacity)
*Lighter (only lifting an 800 gram drill, not an 800 gram drill AND a 2.2Kg battery)

*Cord hanging out back (I can live with that)

So lets get started!!!!!

Step 1: Stuff You Will Need

You will need:

*A drill
*Some fat cable
*Terminal block (optional)

Step 2: Lets Get Started!!!!!

First, you need to remove the battery. You won't be needing that for a long time.

Then, take a screwdriver to the beast. There were 6 screws, none were hidden on my drill.

pop the cover off. You should be rewarded with a mess of wires.

Get your cable. Make a note of the polarity. Find where the battery connector is. I decided to just crimp the cable to the back of the connector. worked well enough.

Route the cable out the bottom, clip it back together and put the screws in.

Step 3: Set Up the SLA

Now you are going to want to grab your ( charged!!!!!) SLA, and set it up for use with the drill.

This basically involves gluing a terminal block to the top of the battery, so the drill can be disconnected if required.

First, get your terminal block. Glue it in the center-top of the battery.

Now, get some cable. hook one end to the terminals of the SLA, and the other to one side of the terminal block. Paint the ends of the terminal block if you want, so you don't get your polarity wrong.

Step 4: Finished!!!!!

You're done!!!

hope you enjoyed my instructable!!!

Please rate!!!!!



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    30 Discussions

    Thanks for the great instructable. I would like to do this with my old 12v ryobi cordless drill. Do you know if I can use a standard automatic auto/car battery charger that is switchable between 2/10 Amps to charge the12v 5ah SLA battery?

    This is a good use of a DC portable drill - especially helpful if you're away from AC outlets for a long time like on a boat or working 'in the bush'.

    There are a couple of things that people have touched on, but I'll spell them out in one comment:

    1. You need thick, short cabling between your battery and DC device - it draws watts as volts x amps. House wiring is 110v so amps are low and cabling can be pretty tiny. When you are using a 12v device that is somewhat powerful, you will need much thicker/shorter wiring. This shows itself as voltage drop and warming wiring--or worse.

    2. Lead Acid- even 'deep cycle etc batteries' - don't like to be used 'all the way'. In fact, if you care about your lead acid battery try to only use it 20% or 50% up. You can get a rough idea of how much 'drill life' your battery has by figuring out how many amps the battery is vs how many amps the drill is rated at. If they give watts, figure it out from watts = volts x amps.

    great idea this, I travel a lot by car, and need everything running off 12v where mains 220v etc is never available. I'll use a big "booster" sealed lead acid battery which I can recharge from the alternator when travelling.

    The SLA (Sealed Lead Acid?) looks exactly like the type used in some computer uninteruptible power supplies (UPSs)

    Thanks for this, just brilliant for what I need - and from some time in the past. Nice .


    1 reply

    i gutted an old battery and wired it to a mail car lighter great....great idea btw

    i'm a bit late here but now it's not wirreles anymore so you can use a 220 v or 120 v drill.
    This is good for a place where is no electricity if you have it's not usefull .

    tried with a car battery sitting at 12.6 volts and the wires just get hot with no movement from drill. mine is a dewalt tho

    Not usually. SLA means Sealed Lead-Acid, meaning that it doesn't have vent ports, and can be tipped in any direction. Car batteries are more often "floodies," which are also lead-acid, but have removable vent caps to allow you to replenish the electrolyte. This cap doesn't seal perfectly, though, and the case isn't completely filled, so they have to stay upright.

    Not always. SLA has no vents. Most maintenance-free batteries have vents which can only be opened with a large screwdriver or pry bar.


    oh yes. You're correct. I didn't read his comment correct. I thought it said "is it an SLA car battery". But all the things you said above are correct. thanks for correcting me!!!!!

    Also remember car batteries are high current but low capacity and don't like being drained, but the SLA shown is probably a more deep cycle than a car battery so can happily be drained and recharged a number of times.

    then keep the engine running that works bcz of a magical device called an alternator

    Well if you have to have your car there it's not quite as portable, is it? I thought the point was that you could still have a more or less portable drill but a better battery life than the original. I know running the car engine would keep the battery topped up, but then you might as well run it off the cigarette lighter socket. The sarcasm is unnecessary.

    A car is portable.But good idea on the lighter socket,you would at least be safe ps i wasnt sarcastic pss the idea would be useful when you work inside the car

    I did as instructed but I don't have enough power from a 12 volt 7 amp lead acid battery.  What battery did  you use?

    1 reply

    Mapmaker, Are you wiring a 12v drill? This won't do much for an 18v tool!