Instructables

Make a cordless drill to run off batteries or a wall outlet

I have a cordless drill that I use mainly in my workshop next to a plug. I found working on projects the battery would always start to die half way through so I decided to make it so I could plug the drill into the wall when working near an outlet and still have the ability to use the battery when I want.
Super easy and it wont ruin your drill.
You can potentially do this for free like i did if you have spare parts laying around

Parts needed:
-drill
-wire connectors x2
-ac/dc converter (I used an old laptop power bar.

My drill is a 16.8V model and the power supply i had laying around put out 20v. Close enough.


First I opened my drill to see the type of connections.
For my drill i needed two male connectors so they can slide into the drills female connection.
Plug the power supply that your going to use in and with a voltmeter test the output to see which wire is positive and which is negative. Mark them so you know which is which
My drill would not run if the polarities were switched.

Unplug the power supply and attach a connector to either wire. i used red for positive and blue for negative.
Plug the power supply in and plug the drill in to the power supply and give it a test.

I hang my power supply next to my work bench and when i need to use it i just plug it in and plug the drill in and off i go.
then to switch to batteries I just unplug the drill and pop the batteries in.
mesadad3 months ago

Great idea. Does this mean you have to take the drill apart to plug the wires in every time you want to use the power supply? If so, may i suggest using an old battery case and modify it so the elctric cord is attached to it. Makes it easier to switch out from electric power to battery power.

wolvmarine1 year ago
You may also splice wall cords to the batteries with resistors in series that will bring the voltage down to what the batteries can take, while the second part of the splice can feed directly to the motor and if need be brought/resisted down to the voltage tolerance for the motor.
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