My bike light attempt

[Rainney]

I need a bright light for night mountain biking, and can't bring myself to pay $400 for one. This is my second attempt, and much better than the first, but I am still having problems. I took a 2 D cell maglite, and cut it down to about a one cell light. The reflector fits nice, but I still need to get up the courage to grind off the threads so the cap fits tighter.

I need my switch on the power side of the driver, so I put a plug in the back cap of the light.

Here are my insides. I think I may have created the Frankenstein of heat sinks. I turned it from a 1.5" aluminum rod. My problem is that I have a wood lathe, so it takes forever, and its not exactly precise. I was too cheap to buy multi-colored wire, and unfortunately hooked up my driver backwards. I put the power on the LED side, and hooked the LED to the power side. One little puff of smoke, and it was done.:mecry:I just ordered two more, and bought wire in colors other than yellow. :D I actually used it for a night ride, and hooked it directly to one battery. It ran great for around a half hour before it started to dim. I measured the temp of the heatsink after the ride, and it was only 80 degrees, so I guess a pound or so of aluminum works wonders.

I'm trying to improve the light. My heatsink rattles when I'm riding rough, bumpy terrain, so I'm trying a new idea. I bought a 1.25 aluminum rod. It saves me all the time with the lathe, but it has too much slop. I added a couple grooves, and some O-rings, and its a perfect, airtight fit. I also removed some aluminum to try and get rid of a little weight. I'm a little worried about the O-rings insulating the heatsink from the flashlight body. Is the massive mass of aluminum enough on its own, or should I add a small, tight fitting, to the flashlight body, disc to the front of the heatsink? Also, does anyone know of a good way to mount two of these to a bike?

 

[PCC]

At what drive current are you going to drive that SSC P7 LED? The mass of the heatsink should be enough to prevent any problems from cropping up, but, that depends on how long you plan on keeping it running and how hard you are running it. Coupling it to the body of the light will allow some heat to escape the light as well, which will help if you plan on running it for hours and hours at a time. That depends on the battery.

If those four holes drilled into the heatsink was an attempt at lightening this up, umm, you need to keep going. I think you lost about 15 grams of weight, approximately 1/2 oz. I know weight weenies, like myself, can get obsessed about weight, but, 15 grams can be the difference between wearing a long sleeve jersey compared to a short sleeve jersey.

 

[Rainney]

I plan on using sku#20329 from deal extreme, so I will have high, med, and low. I also plan on two separate setups, so I can switch from one to the other. I should also be able to weld with the two on high, if the need ever arises. :laughing:

As far as the holes go, there is a large one that runs down the center of the heatsink. I guess I was kind of thinking that the small holes between the O-rings would allow a little airflow, but I'm probably completely wrong. It may be mental, but I would swear I can feel the weight of the single light mounted on my handle bars. With one battery, it weighs just over 500 grams.

I am really impressed with the light so far. Its amazing when your in a dark canyon. Its a small step down from the light on my motorcycle. I can't wait to get it out there with some of my friends, and blow their expensive lights out of the canyon. :nana:

 

[PCC]

Are you using a remote battery pack? With a MagLite of that size you can probably get the two 18650 batteries inside of the thing to keep it simple.

At 500 grams, that's a little over a pound. That's pretty heavy. Yours might be brighter than your friends', but, it's heavier, too. You'll probably keep their back ends warm going up the hills because they will be in front of you with their lighter setups :p

 

[Norm]

Moved to bicycle.
Norm

 

[Rainney]

Are you using a remote battery pack? With a MagLite of that size you can probably get the two 18650 batteries inside of the thing to keep it simple.

At 500 grams, that's a little over a pound. That's pretty heavy. Yours might be brighter than your friends', but, it's heavier, too. You'll probably keep their back ends warm going up the hills because they will be in front of you with their lighter setups :p

I am using a remote battery pack. This is my second attempt at making my own light. I'm sure I will get better, and my lights will weigh less as I get things figured out. Once I get everything dialed in, I'll start looking at putting the driver, and possible power in the body. I figure by the time I get close to spending the $400+ my lights will be just as light, weight wise, and I should have about twenty of them.

So are there any good mounts to put a light like this on a bike's handlebars, or am I on my own?

Thanks for moving this to the bike forum. I don't know why I didn't see it before.

 

[VegasF6]

DX has several different bike mounts, some are a hard nylon/plastic material, too brittle. Some are simply silicone bands, those seem to work much better, though I would still be concerned with a light as heavy as yours. A third type is a combination of hard plastic and velcro straps.

Battery Junction is a friend of the forum, offers a discount and carries several models, including the quasi famous two fish block. Oops, strike that, they carry a two fish block for pumps. Hmm, well it might work.
Also check 4sevens.com

Those are the ones I can think of off the top of my head. They aren't really bike specific sites, but I would imagine they are prevalant as well (bike sites I mean). I did notice a few just now at geomangear as well.