Is there an attainable BRIGHT LED homebrew solution yet?
 

So my current setup uses two large reflector 12V 11W halogen bulbs with a 7AH lead acid battery.

I'd like to upgrade to a Li-Ion battery but I would realistically have to sacrifice some run time. However, if I had more efficient light sources, then I could keep or improve my runtime with a smaller capacity Li-Ion battery.

So are there any LED light solutions available that are nearly as bright as halogen with [b]large reflectors[b]?

There are plenty, most of which are brighter than your current halogen, with 2-4 times the runtime.
See the total geekiness thread.

Nice project, seems we were in the same boat

Do you have a link for the reflector/housing you used?

Hope I'm not violating some sort of cross-forum reference convention but here is a very attractive DIY LED light. Basically a DIY Dinotte light.

That's interesting. What is the lumens on that?

Great link! Thanks


Has anyone messed around with mounting an LED emitter inside the gutted reflector housing of a halogen lamp? I like the large reflectors and am thinking about possibilities in that range. Going to order 3 Cree XR-Es from DealExtreme and a bFlex driver

Yeah.... it's one led, too weak. Until led can pop out 1000 lumens at 3 watt, then I'm sold, because passing 800 lumens for road cycling, it's overkill.

I'm thinking 240 lumens, still crap.
Build two of these, then you're good.

You don't necessarily have to follow the exact instruction on that site, I built one of those with a different drivers and housing cutouts to cut back on the amount of work needed.

I purchased one of these:

http://www.besthomeledlighting.com/p...-GX5.3-S-3W-WD

and mounted it in a PVC housing. I don't think it is quite as bright as a 20-watt halogen MR16, but it is bright enough.

I still think these are the hottest thing out there for DIY'ers right now...

http://www.dealextreme.com/details.dx/sku.6090

It's got a Cree LED in it and it self regulates from 3-18V. Basically you find a way to mount it and put any battery source you have to it and enjoy the nice bright light. I put one in a headlight and I feel like a freight train when I'm out there riding. It has a nice bright hot spot and lots of usable spill too. Eventually I'll buy a few more and wire them up for a 3 light headlight and ditch the mr16 I'm using...

I hope this isn't considered spam, but I'm in the process of putting together a DIY led light kit. Should help with all those annoying choices the beginner needs to make. What LED? What optics work with what LED? Batteries?

More details can be found at:
http://forums.mtbr.com/showthread.php?t=373277

I'm in the process of trying out a few different designs. I'll probably have a few kits available by mid feb.

Mark

Here ya go....

http://www.cutter.com.au

Have a look under the optoelectronics section and you'll find everything you need for a homebrew LED light.

Bah 240? I'm still waiting for someone to come up with a higher power, say 600L+ for a DIY kit. But that looks as polished as the Dinotte knock-off.

The other unofrtunate problem with a 200L Knockoff is you still have to use that lame rubber-band mounting system. Makes it annoying to install/take off the light and there is no swivel option.

The MR11 kit from cutter puts out 750lm. Order the nightlightning head unit, no lame rubber band :)

Word is SSC is coming out with a 370+lm LED sometime this year. I think that's based on 1A driving. Cree should have ~275lm in thier R2 or was it R4..I forgot.

Right now if you're doing DIY and want good bang for buck and still very respectible bright (some may say blinding) the SSC P4 U-bin LED's at DealExtreme are hard to beat at ~$5.50/ea where as the Cree Q5's are $9.00/ea.

The SSC P4's get 240lm @ 1A (if you win the lottery) but after the conversions of ~85% effecient optics plus 85% drivers it comes out to this :

240 x .85 x .85 = 173.4lm @ 1A after effeciencies.

That's if my math is correct. Still working with two LED's gives you 300+ lm.

Not quite, the one amp is as measured at the led itself. In other words, at 85% efficiency for the controller, you'd see: 1 amp ÷ .85 = 1.176 amp prior to a one amp controller. Doesn't factor into led output, but rather to amp load at the power supply.

So assuming no trouble with the power supply end of things, .85 * 240 = 204 lumens output, slightly under 60 lumens per watt at full throttle.

So in a nutshell, we'll be seeing 370lm+ out of a single LED. I'm a newb at this lighting stuff, what does the 1A have to do with brightness?

http://www.candlepowerforums.com/vb/

The transportation - bicycle lighting forum at this site has a lot of examples home made LED lights, and lots of discussion on the electronics used to drive them. Here's a link to a light I made with 3 CREE XR-E P4 LEDs driven at 800ma. Thats about 400 lumens, and it seems as bright as my halogen two bulb unit 10W +15W.

http://www.candlepowerforums.com/vb/...d.php?t=182208

The higher the current the more light. So at 350 mA a CREE XRE P4 puts out about 80 lumens, at 1A its closer to 200 lumens.

My source is coming from the the CPF forums which is currently down on my side at 1833 ET. :( The guys there are light hounds and study the LED's and the workings of LED's intimately. Also I think that SSC 370+lm may not even come out till ~Q3/08 or Q4/08. It seems like the LED's gain about 10-20lm each advancement.

EDIT: CPF is working now. 1837 ET

The 370lm quote was at 1.4A. Probably over 5w and under 70lm/w
There are MUCH brighter LEDs . . . out there but the efficiency is the important point. Current crees are around 100lm/w

The LED output is a function of the current through it. They are most efficient at lower currents. You are much better off driving 4 LEDs at 350mA than 1 at 1.4A... maybe 50% more light for the same power input. Less heat issues too.