Convert a battery drill to wall power

Step 2 Gather your parts (and tools)

First, look at the drill. On the side it will (hopefully) have a description of the battery pack. If it doesn't, look up what a replacement would be. In this case, an old craftsman drill used a 9.6 v, 1400 mAh battery pack. Then find an old, unused wall wart that might work-in this case, i found a 12 v, 1.2 A unit. I figure higher voltage will give a higher rpm, and the lower amperage means less power.

(1 A = 1000 mA)

What I used:

Craftsman Drill/Driver ($5 at a garage sale)
Wall wart (12 v, 1.2 A)
Screwdriver
Sandpaper
Soldering equipment
-butane torch
-solder
-flux
wire cutter (and stripper, if you want)

Comments

[unasimple]

I've done two drills like this.
One a 12v craftsman drill where I used the 12V 750 mA adapter for the charger that came with it. This one seems underpowered.

For the second one a black and decker 18V I used the biggest adapter (physically as well as voltage) that I could find a 30V 500mA and this one seems to work great. Not sure about longevity though but it hasn't melted yet. :)

[m_m]

1400 mAh = 1400 mA for an hour, not 1400 mA. A typical drill battery will not run for an hour, meaning that the draw from the battery will be greater than 1400 mA = 1.4A. You should take this into account when picking a power supply (wallwart) because an underrated power supply is a good recipe for disaster (fire).

An Energizer AA battery for example can push up to 2 A continuously (until it is dead).

[smithy813]

so over rated is ok? (like the one used)

[m_m]

the one used is not over rated. It is rated at 1.2A. A drill will pull more than 1.2A, so the power supply is under rated.

[smithy813]

but is over rated ok

[m_m]

yes

[Peale]

I figure higher voltage will give a higher rpm, and the lower amperage means less power.

Higher voltage will likely mean a faster spinning motor (which may or may not work against you, depending on how much punishment your motor can take by getting this extra juice). But your guess on amperage is wrong. It's rated on draw. Since the wall-wart is rated for only 1.2A and the drill sucks at *least* 1.4, you're going to kill your wall-wart. Esp since drills suck a lot of current at a time.