help with modding light bar off road use only

let me start off by being crystal clear, this will never be used on the road. i have fabricated a magnetic mount so that i can remove the light bar from the roof for when i drive the vehicle on the road. the light bar has been and will only be used for off road purposes only. i purchased a cheap led light bar from ebay about a year ago. its 42 inches wide and has 80 leds. 40 flood and 40 spot. i love the light output but due to the fact that it uses very small reflectors its basically a large flood light. alot of light spills into the treeline of the trail. it literally lights up t the top of a 40 foot tree. seeing as this is all wasted lumens i want to change the inner 40 leds from reflectors to asherical lenses in order to achieve more throw down the trail while keeping the remaining leds for flood. my 3 questions are, is this something that is a realistic idea? and if so where can i get small lenses that are fairly cheap (i dont want to spend more then 100$). and how would i calculate the focal length so i can determine what size lens i need. i do have some experience building and modding flashlights so im not a total noob. below is a picture of the light bar i bought.

http://i.ebayimg.com/00/s/ODAxWDgwMA==/z/kZUAAOxyB9RS14UC/$_12.JPG

nobody can help me out? I just need how to calculate the size aspherical lens I need and a place to buy them from

It may seem like you're being ignored, but what you're asking is a little outside the realm of this part of the board. Homemade/home-modified lights are no good for on-road use, and off-road use is such a tiny fraction of vehicle lighting, that there aren't a lot of answers forthcoming for you.

burro breath said:

nobody can help me out? I just need how to calculate the size aspherical lens I need and a place to buy them from

Click to expand...

Pictures may go a long way. We have no idea what reflector you have right now, what LEDs, etc.

An aspheric may not be realistic.

Pictures go a long way, and may be better in another thread.

Semiman

burro breath said:

nobody can help me out? I just need how to calculate the size aspherical lens I need and a place to buy them from

Click to expand...

The higher the diopter (1000/f where f is the focal length), the larger diameter the aspheric will need to be to reduce chromatic aberration due to dioptric spread at the edges (as it will have a larger optical center), so you don't get a hood-full of "rainbow" from scattering.

In other words, "WOW this is dang complicated."

i cant figure out how to attach images. i took the light bar apart today and there is no brand name on the leds and i do not recognize them. i am 99 % sure that they are not cree leds. how do i attach images?

burro breath said:

i cant figure out how to attach images... how do i attach images?

Click to expand...

You don't *attach* them. You put them on a photo hosting site, or a website you own, and then use the IMG tags, like [img]http://www.colonslash.org/special/carrepair.jpg[/img]. I used NOPARSE tags to show the syntax more clearly.

This is the inside of the light bar. The leds are also very easy to dedome. I managed to dedome the one on the top far left.

Those look like Epistar LEDs.

Yeah...epistar, edison optoelectronics, mason led...

I took apart one of these same bars before too. Not really a whole lot going on electronics wise or optics wise.

Check out Ledil, or Carclo. You can get optics through Mouser, Digikey, Future Electronics.

electromage said:

Those look like Epistar LEDs.

Click to expand...

Except Epistar does not make packaged LEDs ....

Ok so at least we are getting somewhere. How would I go about calculating the focal length so I can use at aspherical lenses. Id like to make at least 40 of the leds throw alot more then they do now. Also if I measure the voltage and amperage going to each led would it be possible to get a ball park estimate on the output in lumens?

SemiMan said:

Except Epistar does not make packaged LEDs ....

Click to expand...

They don't? I guess I've just seen LEDs that look like that sold as Epistar. I didn't realize they were just referring to the die. Do you know who makes those cheap white packaged LEDs? They seem to be the same ones used in the Illumination Supply LED bars.

SemiMan said:

Except Epistar does not make packaged LEDs ....

Click to expand...

Ooops...yep. You are right. They maybe a packager using epistar LEDs. A lot of manufacturers do the same with Cree chips in order to claim Cree LEDs too.

So are they definitely epistar leds? Because then I can easily find optics for those.lol

So im still looking for lenses for this project. I have looked and looked and cant find any. Maybe someone could point me in a direction.

maybe the gizmo-heads in the flashlight area know where to shop components?
http://www.candlepowerforums.com/vb/forumdisplay.php?92-CPF-Custom-Flashlight-Builders-and-Modders