How to Build a Bicycle Light

How to Build a Bicycle Light
You don't have to stop turning the pedals just because the sun goes down. Mounting a light to your mountain bike gives a level of visibility that allows trail riding after sunset. If you want to save some money, you can fashion a bike light at home with materials available at home-improvement stores. The project should be accomplished in a few hours and can be done in a workshop.


Difficulty: Moderate

Things You’ll Need:
  • 10-watt halogen bulb
  • 3-inch reflector cap
  • Discarded flashlight tube or 6-inch length of 2-inch-diameter PVC tube
  • Metal tongue terminal kit
  • Pressure switch
  • Small flat and Phillips screwdrivers
  • Duct tape
  • Zip ties
  • 3.5Ah 7.2V lithium ion battery pack
  • Green, red and white electric wiring
  • 2-inch diameter piece of perf board
  • Handle bar attachment clamp with screw attachments
  • Optional:
  • Large mouthed bicycle water bottle
  • Utility knife
Step 1
Push the 10-watt halogen bulb into the reflector cap. Run the red, green and white wires up through the old flashlight housing or through the PVC tube.
Step 2
Screw the red wire to the red/positive set screw on the tongue mount. Screw the green wire to the green/negative set screw on the tongue mount. Run the white wire to the ground connection and screw in to fasten to the tongue mount. Slide the wires through the perf board openings, so the perf board can rest on the butt end of the PVC or flashlight tube with the wiring coming out.
Step 3
Attach the red, green and white wires to the 3.5Ah 7.2V lithium ion battery pack. Make sure red goes to red, green goes to green and the white ground is connected to the ground terminal. Attach the pressure switch red and green wires into the tongue mount attachments and tighten the set screws onto the wires to tighten them in position. Push the reflector cap with the halogen bulb into the top of the PVC tube or flashlight tube.
Step 4
Wrap the reflector cap to the tube (PVC or flashlight) with three wraps of duct tape. Wrap the perf boat to the butt end of the tube with three wraps of duct tape.
Step 5
Cut off the top of the water bottle with the utility knife and place the 3.5Ah 7.2V lithium ion battery pack into the open water bottle. Run the wires along the bottom of the bicycles down tube and zip-tie it to the frame.

If you want to have the battery elsewhere, run the wiring up your arm, and place the battery pack into a small backpack.

Article Written By Eric Cedric

A former Alaskan of 20 years, Eric Cedric now resides in California. He's published in "Outside" and "Backpacker" and has written a book on life in small-town Alaska, "North by Southeast." Cedric was a professional mountain guide and backcountry expedition leader for 18 years. He worked in Russia, Iceland, Greece, Turkey and Belize. Cedric attended Syracuse University and is a private pilot.

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