This instructable covers a very simple lighting system based on information from http://bicyclelighting.com by Steven M. Scharf. For simplicity, many details are left out of this instructable. For such details, including charts for selecting lights and batteries, more complicated circuitry, and product recommendations, see http://bicyclelighting.com.
The total cost of the particular system shown here, including Altoids gum, window wipes, and battery charger, is about $60. The battery charger can be used for other things, and some of the materials will have leftovers for other projects. This means that two complete lighting systems like the one shown here can be made for under $100.
WARNING: This project involves electricity and heat. Do be careful now.
Step 1: Tools Used
- heat gun
- soldering iron
- wire clipper with jacket stripper
Step 2: Determine Your Needs
- weight, depending on the size and type of battery used
- brightness, depending on the type and quantity of lights used
- circuit complexity, depending on the quantity of lights and switches used
- cost, depending mostly on the battery
For this project, I merely want one constant headlight bright enough to illuminate the road when traveling below 15mph. No high beam is required. No taillight is required. (I find that AAA-powered LED taillights work fine.)
For this limited purpose, one 12V 20W bulb will suffice. To power this system, I will use a 2.3AH sealed lead acid battery. One pushbutton switch will control the light.
For more information about how to determine what lights and batteries to use, see http://bicyclelighting.com.
At the very least, any lighting system will include a battery, a fuse, a switch, and a light.
Step 3: Parts Used
- auxiliary auto light kit (aka racing lights)
- MR16 lamp, with a 12V 20W spot bulb (ANSI code ESX),
- pushbutton switch
- Altoids gum tin
- Velcro stickers
- 2.3AH sealed lead acid battery
- bottle cage
- drain hose connector (rubber with metal hose clamps)
- empty window wipe container
- wire connectors
- heat shrink tubing
- 10A blade fuse
- blade fuse holder
- wire loom
Step 4: Install the Lamp Into the Housing
Step 5: Prepare the Switch Box
I am using an Altoids gum tin. For the pushbutton switch, I drill a large hole in the lid. For the wires to the battery, I drill two small holes at one end. For the wires to the light, I drill two holes in the other end.
Technically, the negative (blue in the picture) wire does not need to enter the switchbox, but it helps to keep things tidy.
Step 6: Wiring
You can rely on multiple connectors to be extra flexible. I do this for a system that I move between bicycles of different geometries.
The majority of time and effort is spent on soldering. I strip about 1" from each wire and butt solder them together. Don't forget to thread a piece of shrink tubing onto one of the wires before soldering. After soldering, slide the shrink tubing over the joint and use a heat gun to shrink it. If you really mess up, you can fall back on electrical tape.
Attach the fuse holder to the positive terminal. Attach connectors where convenient.
Step 7: Mount the Components
To hold the battery, I attach a bottle cage to the down tube. Some find the aesthetics of hose clamps to be repugnant; I don't really mind. I then put the battery inside a window wipe container. Bubble wrap should prevent the battery from rattling around. The container fits quite snugly in the bottle cage, so it won't fall out. The position of the battery is just barely out of the way of both the front wheel and the rider's right foot.
To mount the switchbox, I use some Velcro stickers at the top of the down tube.
To mount the light, I wrap a metal strap (designed for mounting a bottle cage or something) around the left fork tube. Some lights have much better mountings that this one (but few are as cheap).
The picture of the blue Raleigh shows another lighting system I made. That system has two lights (high and low beams), requiring two switches and a 7Ah SLA battery (which weighs 6lbs).
Step 8: Charge the Battery
When attaching a charger, be sure not to reverse polarity. Attaching a charger backwards may completely destroy your battery very quickly. Also, I recommend a "smart" charger to avoid overcharging your battery. Overcharging can destroy your battery and even injure you.
Step 9: Wait for Night and Ride
Definitely test ride your bike before you need the light for a long trip. You will probably find that you need to adjust the angle of the lamp. Also, you may wish to reroute some wires for convenience or safety.
Lastly, like Jack Burton, never drive faster than you can see!