Battery Adaptor for Cordless Tool





Introduction: Battery Adaptor for Cordless Tool

I had a whole set of 14.4 Volt cordless tools including flashlight, small circular saw and a drill.
First the charger went, then the batteries died, and then before I could buy replacements the company then switched to the 18V format and dropped all product support for the 14.4V line.
I purchased a new 18 Volt drill from another manufacturer in protest but it really wasn’t as good as my old one, the chuck slips when drilling and the drill clutch doesn’t seem to handle torque well.
So how to resuscitate my old tools cheaply?
I had two 18V batteries and chargers from other tools and when I jumped them to the 14.4V tools they seemed to run okay. The challenge then was to convert a 14.4V battery into an adaptor.

Step 1: Step 1 Salvage

Gut the battery, removing the NiCD batteries inside and safely recycle them. Salvage the clips off the battery that serve as the connectors to the Tool.

Step 2: Step 2 Solder Some Bits You Salvaged

Solder on a new wiring as needed for the clips

Step 3: Step 3 , Glue the Terminals Back In

Glue into the battery housing part that fits into the tool.
Note the polarities carefully!!!!!!
I use common plastic seals-everything glue as it’s also waterproof and serves as a good insulator

Step 4: Step 4 Solder in a Clip to Attach to the New Battery

Solder on a clip to attach to the battery. I used a piece I salvaged from inside an obsolescent cordless tool. ( they are good for something) and wirenuts to make sure nothing comes apart.

Step 5: Step 5 Cutting the Base to Fit the New Battery

Use the 18V battery as a template and cut out the oval from the bottom of the 14.4V battery case.

Step 6: Step 6 Reassemble and Glue on Something to Hold Them Together

Reassemble the 14.4V (no longer a battery) adaptor.
Glue on some salvaged hook and loop fastener strapping.
This pic shows the new battery clipped to the adaptor but not yet inserted

Step 7: Step 7 Insert Battery Into Adaptor

Connect the new battery via the clip and insert into the adaptor.
You may need to cut the hole a wee bit wider than than the battery's neck to allow the clip to pass.
Fasten the straps to hold it together

Step 8: Step 8 Polarity Check

Mark what side and what colour wire your polarities are on the adaptor so you don ‘t short out your tools by mistake. I have one 18V battery with the positive and negative the same side as the adaptor and one that is reversed......

Step 9: Step 9 Inset Into Tool

Step 9
Insert into your favourite tool!

Now you can get back to fixing all those things you said you’d get around to if you only had tools that worked.

I haven't run into any problems so far with the difference in the voltage. No guarrentees on that by any means. Matching voltages is preferrable but close will probably work fine. 14.4 and 18 might work okay, 9.6 and 18 will probably melt down but who knows......



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    Hi ! Once you've fabricated the addaptor, you're replacement battery pack could be wired to a voltage closer to what's needed. Say 9.6v needed... take a 20v battery pack, open it up. rewire your batteries from series to series/parallel; if possible. It depends on what you find after you've opened the battery pack.

    electrics are black magic to me, but i have a 12v dewalt. reckon a similar approach is feasible...or is it too big a jump from 12 to 18?

    Thanks! Hard to believe so many people have looked at this and my other battery hack instructable! Hope they find useful ways to keep old tools working.

    I agree with dendave.joe, I have dropped my Milwaukee drill off the roof, off of ladders and abuse it on a daily basis. I also know for a fact that I can get any part for any of my Milwaukee power tools including batteries. It always pays to buy high quality tools

    yea me too with my dewalts

    I've been using my Hilti hammer drill, Makita drills and impacts & Milwaukee sawzall for 15 years with a few battery pack cell replacements since I purchased them. Hilti, 20 years (corded) Sawzall also corded, 15 years, & Makita Li-on since I replaced my Dewalt Nicd 6 yrs. ago. I've got a Milwaukee 3.6 volt screwdriver which will do darn near everything the Makita will do and is my most used tool. I'm an Electrician destructing, drilling, and screwing for a living. Handy Dave's philosophy is undeniable. You truly get what you pay for and if & when they go down they'll survive homemade batterie's, alternate power sources and an infinite variety of DIY repairs. The additional cost is more than negated when you have no complete tool systems being tossed in the dustbin. My wife doesn't get it or approve but if I allowed her to purchase I'd be pitching Ryobi's once a month.

    Wyle_E suggested (Jun 19)that "You could make a similar adapter ... to run portable tools from a car battery." I tried that with my 12v Black&Decker;, but disconnected it REALLY quickly when smoke came out of the drill's vents! Why would that happen? 12v car battery, 12v drill... Has anyone successfully done this?

    Yes, the drill was 12v and the battery should have been 12v. The drill overheat could have been cause by one of two things:

    1. As someone else here mentioned, car batteries vary in output voltages slightly. The battery could have had an output voltage slightly above 12v. OR...

    2.The wire you used to connect the car battery to the drill was too thin. That drill is going to draw 12v at around 2 amps, (depending on the drill). For this reason, I would guestimate you should use a wire no smaller than 10 Gauge, for both positive and negative leads. If the drill was unable to draw the current needed, this would cause either a voltage drop or increase (can't remember which right off hand) either of which means death to the drill.