With the days getting shorter (and the fact that I usually ride early in the mornings before work), I was forced to start thinking about lighting for my trail bike. A quick look at the offerings on the market and I just wasn't impressed with what was out there....at least not for the prices they are asking. I can't justify spending over $300 on lighting, and the ones that wee cheaper just didn't put out enough light. So, I set out to make my own, with the goal to spend as little as possible.
I started thinking that I wanted to use a Xenon bulb and ballast and decided to pull the aftermarket Xenon bulbs and ballasts out of my car (I have an OEM BMW Bi-Xenon retrofit kit waiting to go onto the car in place of the aftermarket stuff). This aftermarket kit, which I got for free from a friend that works for the company that makes them, has the smallest ballast on the market for a 35w Xenon kit and uses H1 rebased xenon bulbs. Perfect, all I needed was a reflector and housing to fit it into.
While searching around the shop (I'm a technician for BMW), one of my co-workers had an old, aluminum cased D-cell flashlight that no longer worked that he donated to my cause. It also had an aluminum, chrome plated reflector which was a plus since a plastic reflector just wouldn't cut it. I cut it down, and found a plug to seal off the cut end (will eventually get it machined so that the end cap from the flashlight can thread onto the back. Just wanted to get it together for now and see if it all works before I go spend the money at a machine shop). From there it was just a matter of setting the bulb into the reflector (I adjusted the bulb so that it created more of a spot beam pattern), drilling a hole in the plug for the wiring and grommet to pass, and assembling the unit.
Foreseeing that heat might be a bit of a problem, I thought a little heat sinking might help. A dig through my old RC car gear came up with a perfect solution. An old clamp-on motor heat sink fits the D-size body of the flashlight perfectly. I stripped the blue anodizing and slapped it on. For a handlebar mount, I found an old seatpost reflector mount, and drilled and tapped some holes in the bottom of the light assembly.
And that's as far as i've gotten so far. Thus far I've used stuff that I've been able to piece together and haven't spent a penny. The only thing i'll need to spend money on is the battery to run it out on the trail. I've tested the ballast, etc. with a 14.4V battery from my electric impact gun and it works perfectly. Just need to find a suitable 14.4V battery that has enough capacity to run it for at least an hour and a half. The Ballast itself draws just under 6amps at startup and about 3.4amps when at operating temp so i'm looking at some 14.4V 5ah NiMh batteries as a possibility. Anyway, here's the pics:
Front of light:
Rear of light:
Light with ballast and wiring, etc:
And some pics of it mounted on the bike:
For the ballast and wiring, i'm planning on strapping it to the side of my frame using some double sided tape and zip-ties. Should be pretty secure and out of the way. I had the assembly hooked up to a constant 14v power supply while I was at work one day to monitor how hot the light gets and it wasn't too bad. The heat sink definitely helped, and it puts out A LOT of light. The xenon kit is rated to put out over 3200lumens, so this one bulb probably puts out half of that. Once I get a suitable battery and can get it out onto the trail i'll post some beam shots, etc. Anyway, just wanted to put my latest little project out there. Comments and criticisms welcome...
Hermosa Beach, CA
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