With summer soon approaching in Australia, the appeal to ride in the cool of the night is evident. Although the cost of a decent bike light is a minimum of $200-300. This guide will show you how to develop a mountain bike light utilising a small LED light bar (usually used for 4WD's) and a cordless drill battery for under $100.
Step 1: Materials
For this project, you will need:
- Small LED Light Bar - preferably with spot and flood light combination
For this project I used a STEDI ST3501 6.5 inch 30W super slim LED light bar (as pictured) for $60
- Makita battery terminal: part number 643838-6
- 3D printed battery mount (see attached)
For this project I adapted a design by GPlatek: http://www.thingiverse.com/thing:352094
I added two holes 64mm apart so that the battery mount could be attached to where the drink bottle holder would normally sit.
- Cable ties, female spade connector, M5 0.8mm spaced 20mm bolts
Step 2: Assembly
- File back the 3D printed battery mount to enable the battery terminal to be inserted - it will be a tight fit
- Attach the wires from the light bar to female spade connectors and crimp/solder together and then connect to the male spade connectors on the terminal (pos and neg terminals specific)
- Mount the assembly onto the bike using the bolts
- Using cable ties, tidy the cables to the underneath of the bike
- Mount the light bar to the handlebars, options include:
- Use the standard brackets that come with the light bar, using thick cable ties and a rubber strip to protect paint
- Purchase a light bar tube clamp style bracket (as pictured) - measure the thickness of your handlebars prior
- On/Off switch
- Dimmer switch
Step 3: Test and Enjoy
I found that a 1.5 amp hour 18V Makita battery powered my 6.5" light bar for almost 2 hours before I noticed dimming.
You may have a different brand of drill battery that you wish to use and I am sure there are plenty of other 3D printing designs out there which you can adapt to suit your needs.