Take apart the battery. Determine the positive and negative leads. On mine white = negative, black = positive (similar to wiring a house).
Aquire a cord. The wire I scavenged is suspected to have come off of an old vacuum. I would recommend scavenging for this project to keep costs down. I also found some banana plugs to make it easier to connect to a power supply. I considered using some old test lead alligators.
|The kind of Banana Jack I used|
Remove the batteries and wire together. I actually left some of the batteries in the casing to add some counterbalance. I then soldered on the wire, punched a hole in the case to let the wire out, and hot glued everything together.
Test. My next step was to hook it up to a car battery and test it. It worked! for a few seconds. Then the burnt smell.
The drill did not like being run on a car battery. There is a large diode inside the drill that I burnt out. Luckily, I found a replacement in a box of old hairdryers that we happened to have on hand.
With the replacement diode in, I took it over to a lab and tried it out. It worked fine. There was still a slight burning smell, but I suspect that may just be dust in the motor from years of non use. Overall it seemed to work ok. The video below will give you a peak at the power supply readout during testing.
Some might call this a wasted Saturday afternoon, and they are probably right. However, if you enjoy tinkering with things, making a corded cordless drill might be right up your alley.