AndreZA Posted April 17, 2008 Share For those who are Jhb based' date=' I got my 2500mah Sanyo's for R 25.00 per cell from a small battery supplier called SJ Andrews in Marlboro. [/quote'] So that is R100 for 4. Good price IF you are in the area Link to comment Share on other sites More sharing options...
sampie Posted April 24, 2008 Share Hi WillehondCan you maybe send a photo where using the light outside, will be interesting to see a 10 and 20m view. Link to comment Share on other sites More sharing options...
Willehond Posted April 24, 2008 Share Hi Willehond Can you maybe send a photo where using the light outside' date=' will be interesting to see a 10 and 20m view.[/quote'] Sampie, I am a sucker for a challenge. Consider it done! I will try to get a comparison shot outside with my other lights. I have been planning to do it anyway. Link to comment Share on other sites More sharing options...
mountain_lion Posted April 24, 2008 Share OK, I did some tests comparing light output of the 1W Luxeons at various load currents. Since I don't have a lux meter, I used my camera. I placed the light (3x 1W LEDs with Trilens Narrow Beam Lambertian collimator) on a table and pointed it at the ceiling (white).The camera was mounted on a tripod, taking spot measurements at the center of the light spot on the ceiling. I recorded load current, F-stop & lens opening with the camera set to 400 ISO and used the formula on this page to get a lux value (not accurate at all in absolute terms, but fine for relative comparison). This confirmed what I guessed: At first light output follows current almost linearly, but from approx 600mA light output starts to taper off and increase in current does not yield much increase in light.In fact from 800mA to 1000mA LED current, my camera reported the same light reading. Bottom line: There is not much benefit in running 1W Luxeons at a load current of more than 600mA. So driving 3 LEDs with a Buckpuck driver from 8 x 1.2V NiMH cells will do fine. Link to comment Share on other sites More sharing options...
Hog_ Posted April 24, 2008 Share Very informative! Thanks ML! I'm ordering my goodies next week (have to wait for payday), then it's time to whip out the ol' soldering iron! Link to comment Share on other sites More sharing options...
Pocketbikes Posted April 24, 2008 Share Firstly, to all you pioneers. You guys have inspired my to build a light and I don't even have a MTB yet I have only seen the Grandcell in 1.2v NiMH, but seen PureEnergy which are 1.5v, but are alkaline rechargeable. I will check my cost price on the Vanson 8 cell charger and Samsung Pleomax 2500 mAh tomorrow and post my findings. Pocketbikes2008-04-24 14:30:44 Link to comment Share on other sites More sharing options...
mountain_lion Posted April 24, 2008 Share I am considering getting the Maha 800S charger. Ebay seems to be the best source. Have not found it locally in SA at all. Link to comment Share on other sites More sharing options...
sampie Posted April 25, 2008 Share Must the LEDS be in series or parallel. In parallel one can maybe play around with the option to have 1, 2 or 3 leds on to save the battery Link to comment Share on other sites More sharing options...
mountain_lion Posted April 25, 2008 Share LEDs can be connected in series or parallel, but control is much easier in series. The LEDs are driven at constant current using a driver such as the Buckpuck. One Buckpuck can drive several LEDs in series with the same constant current supplied to all. If you connect in parallel you can use a lower supply voltage (i.e. less batteries), but if you use a single driver, the current is the split between the LEDs i.e. a 1000mA driver will supply 500mA to each LED if you have 2 in parallel (assuming the 2 LEDs have identical impedance). With the Buckpuck, it is easy to control the output current (potentiometer between control and reference pin) so you can dim all the LEDs instead of switching some off. Link to comment Share on other sites More sharing options...
markStockton Posted April 25, 2008 Share So driving 3 LEDs with a Buckpuck driver from 8 x 1.2V NiMH cells will do fine. Thanks, you have saved me a fair amount of time and money. Link to comment Share on other sites More sharing options...
Willehond Posted April 28, 2008 Share Hi Willehond Can you maybe send a photo where using the light outside' date=' will be interesting to see a 10 and 20m view.[/quote'] Sampie, here it is, the shrub at the back is 20metres away from the light. Taken wit the light I FINALLY finished assembling today. Very happy! Link to comment Share on other sites More sharing options...
mountain_lion Posted April 28, 2008 Share Nice WH! My first version was also completed over the weekend and had its first test ride earlier tonight. Works very well. Photo's and beam shots to follow shortly. Link to comment Share on other sites More sharing options...
mountain_lion Posted April 28, 2008 Share Here is my LED light after some time spent in my dad's garage: The guts: 8 x NiMH AA powering a 1000mA Buckpuck 3021 LED driver, soldered onto vero board with dimming resistor, 3 position toggle switch (off, high, dim) & connector for the LED wiring. The switch has a rubber cover and is mounted on the handlebar with a piece of inner tube. The driver board is also covered by inner tube for electrical isolation and protection against the elements. Batteries and driver are mounted on the bicycle frame in a pouch with velcro strap. I used an old PC CPU heatsink to mount the LEDs on. The heatsink was machined on a lathe to be a tight fit in a section of 50mm PVC pipe. The lens is held in place with a PVC coupling which was cut down on the lathe. 3x 1W Luxeon emmiters: The assembled light, which is attached to the bike stem with an old LED flasher mount: I will take some photos of the light mounted on the bike in day light and post later. Link to comment Share on other sites More sharing options...
Willehond Posted April 28, 2008 Share Nice setup mountain lion! Any closeups of the dimming setup? I like that idea.I will post some detailed pics of my setup (hopefully tomorrow), but it's way too late know. I have to get up early to actually use the light! Link to comment Share on other sites More sharing options...
mountain_lion Posted April 28, 2008 Share The beam shots. The garden shed is approx 17 meters from the lights. The photos cover 15m, i.e. from about 2m in front of the bike. All photos 8 seconds @ F8 without any post processing. Control photo (no lights on): One of my previous DIY light sets using 2 x 10W Cateye lights @ 6V: A slightly modified 6V Vista Light set using 1x10W + 1x5W halogen lamps: Finally the new LED light with 3x 1W Luxeons driven @ approx 550mA (my high beam setting; I forgot to take a low beam photo ).I am still experimenting with the vertical aiming of the light. Note that beam shot photo's are just an indication since much depends on the camera settings used. 8s is the longest exposure that my camera can do. Longer exposure will also show up the lower level peripheral which is useful to show up the edges of the trail. In practice the lights are much brighter than in the photo's above and the new LED certainly out performs the other two light sets. mountain_lion2008-04-30 09:52:22 Link to comment Share on other sites More sharing options...
mountain_lion Posted April 28, 2008 Share I found this heat sink in an old PC, Total over kill for 3 x 1W Luxeons driven at 550mA, but as you can see the tri-lens fits inside so nicely it just has to be done. (perhaps I can upgrade to 3W Luxeons later). So LED light version 2 will be attempted soon... Mrs mountain_lion has taken possession of the first set, so I need another for myself anyway... Link to comment Share on other sites More sharing options...
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