Awhile back, I bought a pair of those clip on LED lights that attach to the arms of glasses. At first, they worked great. But after a few hours of use, the button batteries slowly died to a point that they became useless. Continually replacing button batteries, (mine had three per each light) wasn't very economical.
I had an old Canon S100 digital camera in my junk pile, (the LCD was broken). I also kept the battery charger and two Li-ion 3.6V batteries. I figured I could use the Li-ion batteries to power the LEDs.
Hot glue gun
Clip-on LED lights - Electronic Goldmine - G16248 - $2.95
Tic Tac container
Double sided tape
1/8" foam rubber
Can of Brain Toniq
Step 1: Make Battery Plug (optional)
Punch (using a hand punch) or cut (using tin sips) some round contact plates from the thin brass sheet. The contact plates need to be about the same diameter of the button batteries. Two contact plates are needed for each plug - positive and negative. Make sure to sand off the finish from the brass plate first.
Next, cut off about 3/8 inch length of 3/8 inch dia. dowel. Cut two pieces, one for each light. File a shallow notch on the top and bottom of the dowel plug. This allows room for the lead wires.
Using 26awg stranded wire, cut off two sets of leads, one for the left light and one for the right. The left leads should be about 15 inches long, the right about 6 inches long. Strip then solder these leads to the contact plates.
Hot glue a pair of positive and negative contact plates to ends of the dowels. Twist the leads together and heat shrink the plug for a neater appearance.
Using a Dremel, make a small notch in the light's battery compartment door. This allows access for the wire leads from the plug.