Hand Crank Generator / Battery Charger

Years ago I had converted an old cordless drill into a hand crank generator, I got the idea from an article in Everyday Practical Electronics magazine the September 2009 issue. While the generator worked I could only get 3 or 4 volts max. out of it. I just couldn't turn it fast enough to get a usable (to me) voltage out of it. Then I remembered that I had a Hand Crank Grinding stone that could be mounted on a work bench or board.

The video can be seen in step Three.

Step 1: The Parts Used

A Hand Crank Grinding Stone

The completed cordless drill converted into a Hand Crank generator,

-The drill was a 19.2 volt Craftsman drill that I had picked up at a yard sale. ( I actually got 4 of them without batteries) The drills didn't work, I have the same drill that I had bought years before. The reason mine still works is that the power transistor that is part of the speed control circuit was fastened to a substantial copper heat sink. The failed drills same model but later manufacture had an inferior aluminum heat sink that just couldn't dissipate heat fast enough under normal to medium use and so the power transistor failed. I imagine that there were a lot of returns.

Some plywood, 2 x 6 board, 4 x 4 post, assorted screws and bolts.

I also used a high current bridge rectifier with spade connectors on the output of the drill.

The reason for the bridge rectifier is that no mater if the crank is turned clock-wise or counter-clock-wise the out put polarity is always the same. I hooked the o/p of the drill to the AC terminals of the Bridge Rectifier the o/p from the Bridge Rectifier comes from the + and - or the positive and negative terminals.

A 1/2 inch by 3 inch spring, a 3 inch piece of 7/16" threaded rod, a 3" long extension nut.

Step 2: Assembly

The drill was previously mounted to a board, I then mounted it to a larger piece of plywood. It was also elevated at the back side of the drill so that the chuck of the drill would be level with the mounting of the Hand Crank Grinding Wheel.

On the grinding wheel I attached the extension nut in place of the original nut ( I also used tread locker) then I screwed in the 3" piece of threaded rod with tread locker as well, then I screwed on the spring ( this turned out to be harder than it sounds).

Next I attached this completed assembly to the chuck of the drill. Then I measured and cut some boards to get the right elevation. Then those boards were fastened to the plywood that the drill is attached to. I used 3" wood screws.

Step 3: Demonstration, Proof of Concept.

Demonstration Items:

Two Fluke digital meters, a 10 watt 12 volt halogen deck light, my camera on a tripod for the video.

One of the meters was set to the d.c. amps setting, the other to the volts d.c setting.

The volt meter was attached to the + and - terminals of the bridge rectifier.

The current meter was hooked up in series with the 10 watt lamp load.

During operation I was able to get .8 amps at 13.45 volts out of the Hand Crank Generator to light the lamp.

If you notice some flickering of the meter displays this is from the leaves of the trees moving in the wind as I videoed it outside.

To see video click on show all items on the pictures, the video is at the bottom.

Step 4: The End

I made this to see if I could get enough voltage out it to charge a battery, it should, but your arm would get tired. I'm glad it worked so well!