DIY Homemade 12 Volt Lightbulbs

Mount the 12-volt light fixture on a wall or ceiling, using the screws supplied with the fixture and a screwdriver. Strip off 1/2 inch of insulation from the tip of the positive and negative wires extending from the light fixture, using a wire stripper.

Strip off 1/2 inch of insulation from the tip of an electrical wire (red), and from the tip of another wire (black). Splice the red wire to the positive wire from the light fixture, and splice the black wire to the negative wire from the light fixture. Wrap the spliced wires securely with electrical tape.

Punch the knockout on top of an electrical outlet box. Mount the box on a wall close to the 12-volt light bulb. On a blank outlet box faceplate, drill a hole with a diameter equivalent in size to the circular neck of a 12-volt toggle switch at the center of the plate, using a power drill. Unscrew the lock nut of the toggle switch, mount the switch onto the faceplate and replace the lock nut.

Route the black and red wires neatly along the wall or ceiling from the light fixture to the outlet box. Use cable staples to fasten the wires onto surfaces. Slip the red wires through the knockout and pull the wire from inside the box. Cut the red wire inside the box with diagonal pliers, but leave at least 6 inches of extra wire dangling inside the box.

Strip off 1/2 inch of insulation from the end of the red wire. Wrap the bare tip of the red wire clockwise around any of the two terminal screws at the back of the toggle switch, then tighten the screw firmly with a screwdriver. Strip off 1/2 inch of insulation from the tip of a new segment of red wire and slip the wire into the box. Wrap the tip of the red wire around the other terminal screw behind the switch. Tighten the screw firmly and flip the switch to its "Off" position.

Run the red wire coming from the switch and the black wire coming from the light fixture to the 12-volt battery. Cut the wires upon reaching the battery terminals with diagonal pliers. Crimp an eye terminal onto the tip of each wire, using pliers.

Loosen the lock nut of the holding bolt on the positive and on the negative battery terminal clamps with a wrench. Remove the lock nut of the positive terminal clamp and slip the eye terminal of the red wire (positive) onto the holding bolt. Replace and tighten the lock nut. Follow the same method to attach the black wire (negative) to the negative terminal clamp.

Cut the red wire about six inches from the battery terminal and strip off 1/2 inch from the tip of each cut wire. Splice each end of the cut wires to each end of the wires from an in-line fuse holder. Cover the splice securely with electrical tape and plug a 12-volt fuse into the use holder.

Plug the negative clamp (black wire) onto the negative battery terminal and plug the positive clamp (red wire) onto the positive terminal. Tighten both clamps with a wrench. Flip the switch to its "On" position to test the light.