Solar Charged LED Running Light With Flashing Brake Light for Bicycles




Introduction: Solar Charged LED Running Light With Flashing Brake Light for Bicycles

About: Been tearing stuff down and putting it back together my whole life. "To Invent you need a good imagination and a pile of junk." -Thomas Alva Edison
So after researching the laws to make my motorized bicycle legal in California and sending for the license plate, I have decided to work on the brake light while I wait for the plate.

After a couple days of looking at other peoples' designs for their brake light, I have come up with my own design to have the brake light come on and flash when I apply the brakes. It does not involve putting a push button switch on the handlebars or inside the brake lever, but putting a switch on the brake assembly of the rear tire.

If you want a brake light on your bicycle or motorized bicycle, then all you need to do is follow the instructions in this Instructable. 

This design will work on a bicycle or a motorized bicycle because I do not have the battery charging off of the motor. Instead I have a solar panel installed to charge the battery even if I'm not riding it.

Step 1: Materials and Tools

Parts/ Materials
  • Soldering Iron
  • Drill with Drill Bits
  • Socket Wrench Set
  • Screw Driver
  • Heat Gun
  • Saw for Plywood
  • Wire Strippers
  • Wire Cutters
  • Rivet Gun with Rivets

Step 2: Circuit

The picture is a circuit that anyone should be able to follow. I did not put values for the components because I just used whatever parts I had that could handle the voltage from the battery. The Solar Panel I bought already had the blocking diode so I did not have to worry about the values that were necessary. The diode keeps the battery from being drained when the solar panel is not receiving sunlight. 

Step 3: Flashing Module Modification

After soldering the flashing LED kit together and testing the circuit, I soldered a red 20 gauge solid core wire to the positive and a black wire to the negative. I then snipped one of the LED's on the circuit board and connected a yellow wire by soldering it to the positive anode of the LED that was snipped.

After soldering the yellow wire, I used heat shrink tubing to cover the anode/wire combo so the it does not touch the metal body of the switch. I then drilled a hole for the LED still hooked to the board and a hole for the wires to come out of the project box. I used heat shrink tubing to keep the wires together. After positioning the circuit board in the center of the project box, I used wooden sticks and epoxy to secure the board to the bottom of the box. I let the epoxy harden a little before I place the top of the project onto the bottom half so that the circuit board will be in its final position. 

Step 4: Brake Light Mount

For the brake light mount, I used a piece of 1/8" plywood and used the mounts on the back of my seat that are made to hold a fake license plate as the mount. It works well for mounting a brake light.  Before hooking it on the bike, I primed and painted the piece of plywood black so it does not really look like a piece of plywood hooked to the bike.

Step 5: Modifying the Pelican Box

I decided to use a Pelican box from Frys as my battery box. The box had to be modified in order to contain the components and hook onto the bike. The first thing that you need to do is lay out all the components inside the box in order to find the best possible layout for those components. The next thing you need to do is decide how your going to be mounting the box onto the bike. The best way I found to hook the box onto the bike was to make a mount out of steel and have it hook to the luggage rack of the bike as a little saddlebag. 

The Mount-
I mounted the box as a mini saddle bag on the side of my luggage rack. In order to do this I had to weld a steel plate onto the supports of the luggage rack. After painting the steel bracket, I positioned the box onto the steel plate and drilled three holes the same size as the bolts that were going to hold it on. In between the steel plate and the box, I placed a rubber grommet onto the bolts in order to cushion the box from violent vibration.  

I decided that the killswitch for the whole system should be on the side of the box. I took the toggle switch and used a drill bit sizer to find the smallest drill bit possible for the base of the toggle switch to go through. I then drilled the box in the spot that I wanted the toggle switch to be in and used silicon to secure it to the box. 

Main Wiring Harness Hole-
The last hole to be drilled is the main hole that all the wires will be going through. After determining the best position for the hole and choosing a rubber grommet that will fit all the wires you plan to put through, drill the hole through the rubber liner and the plastic of the box.  Place the rubber grommet into the hole you drilled for the wires.

Step 6: Mounting the Brake Light Switch

I believe that this was the hardest part of the whole project. I came up with many mounting options, but the best one I found was the one shown below.  It won't interfere with the brake assembly and hooks directly onto the frame. 

First step after coming up with how you want to mount the switch is to make a template out of paper. You can bend the paper into any shape you want and it shows you how the copper will be bent.  I transferred the template I made by tracing the paper using a sharpie.  I then cut the copper using a pair of tin snips. 

After seeing if it will fit, I used pieces of heat shrink tubing in order to give the copper some type of finish and also to protect the paint on the frame from being scratched.  I then drilled a hole for the bolt that mounts it to the frame and a hole for the rivet that will hold the switch in place.  After connecting the wires to the switch according to the schematic, I used heat shrink tubing to protect the blade connectors from the elements. 

Step 7: Putting the Components Together

Just follow the schematic for the wiring. Just make sure that the wire is long enough to reach where it needs to go. It is best to use bullet connectors in order to connect the brake light to the battery box, but I did not have any so I just soldered the wires together and used heat shrink tubing to cover the connections. This is not a good idea because soldered connections can come loose due the vibration involved in riding this bike. 

I also added in the solar panel that I bought from harbor freight in order to charge the gel battery when not in use. I have not made a mount that I am happy with at the moment so I just connect it whenever I don't use the bike. I would like to hook it into the system so it's on the bike all the time, but  for right now it gets disconnected whenever I ride the bike.

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