Flash Light 18650 Conversion (2x D-Cell to 1x 18650)

This is an adaptor for replacing 2x D cells with a single 18650 lithium battery. Just print off and add in a nickel strip for contact.

The lithium battery will give a bit higher voltage, so it will likely overdrive the LEDs a little bit. On the cheap LED light I made this for it doesn't seem to be an issue. Most LEDs generally take around 4V without major issue.