LED gurus, your help is needed. How do I power LEDs from the batt w/o frying them?

[MetalMaxima 10+ year member]

Req is 100% correct. I went out to my car and tried this last night and everything worked perfectly fine! //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[req 5,000+ posts]

neah yeah neah neah neah!

 

[Justintoxicated 10+ year member]

technically, if you just set up the LED's to run at the max voltage for the car - ie 14.4 (like i used in my picture) you arent going to be frying anything, because it will rarely always be 14.4, and if it drops, thats even better for them.
so why go thru all the trouble. mine are working just fine.

and luxeon stars are all good with a bag of chips, but you have to heatskink them, and they put out an awful lot of light for 'accent lighting' //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

You Missed the point.... and yes .5V difference in voltage across an LED can mean life or death for it, but yea if you set them up for 14.4V they should work, although Automotive power supplies tend to have spikes and other things that can damage the LED's so your right best bet is to not use them at their max brightness maybe 2/3s of of it, or REGULATE the curent since LED's are actualy Current sensitive devices.

for the guy who blew them in series that is what I am talking about... If you regulated the current they would all be fine and operating at the voltage they are supposed to operate at! The spikes in power are absorbed by the LM317T (which itself if boarderline for automotive purposes). If you wired them in series I'm suprised that they all blew though rather than just one of them.

If you use resistors and wire them for constant voltage (which a car does not have) THen I would set them up for 16V to be safe and deal witht he reduced brightness which the car drops as low as 12V...

P.S. My Friend is going to weld me up an amprack which will contain both amps and have a low powered super quiet fan blowing through it to keep them cool. The amprack will be bolted under the seats and hidden fro view sept form in the rear seats, He has plans to use plexy for enclose the amps and we will be using Luxeons for accent lighting, if it's too bright I an always adjust the brightness to the desired level.

 

[Rattlebrain 10+ year member]

Not to jack the thread but..... I have a black LED I would like to use. (robbed it out of one of the kids toys) Is there any way to tell what volt..etc it is?? Without blowing it.

 

[djman37 5,000+ posts]

He has plans to use plexy for enclose the amps and we will be using Luxeons for accent lighting, if it's too bright I an always adjust the brightness to the desired level.

I have a flashlight with a 1 watt Luxeon in it, HOLY LORD is it bright! It's the bat-wing i think? It has side discharge to a colmunating(sp) lens. Arc-welder type bright.

 

[Justintoxicated 10+ year member]

I have a flashlight with a 1 watt Luxeon in it, HOLY LORD is it bright! It's the bat-wing i think? It has side discharge to a colmunating(sp) lens. Arc-welder type bright.

yea they can be bright! the High Domes tend to be even brighter, and non binned LED's are typicaly less bright than the ones used in custom flashlights. What kind of flashlight is it anyways? If it is the kind you get at costco they tend to not be as white or bright as flashlight mods from people who are picky about bin codes. Still should look extreamly white compaired to incan though thats for sure! There are some pretty significant variations even from 1 wat Luxeon to 1 watt Luxeon or from 3 watt luxeon to 3 watt Luxeon.

You should see some lights in my collection. lol

I'm planing to build a 5 watt Lux V with a very white but not the brightest bin code VWAsomething bin I wish I could find a or X bin LuxV led with a perfect white color to it for under $80... The light will run on Rechargable PILA Lithium Batteries and will be housed in a 2C Maglite body, should be MUCH brighter than even the huge 6 D cell mags, and rechargable

Never sceen a black LED, so I have no clue as to help you.

 

[djman37 5,000+ posts]

i got it here. http://www.x-tremegeek.com/templates/searchdetail.asp?T1=142+0342&dept=2gd&search=2gd20&child=

there's also a waterproof one from Inova that I like, but it doesn't use Luxeons. A couple of our engineers have the Luxeon focus-able maglite replacement.

 

[Rattlebrain 10+ year member]

Never sceen a black LED, so I have no clue as to help you.

Just like a black light you would buy at Spencers to make florescent colors glow. Just in a LED form. I would get a picture of it but I cant find the little Fugger right now. It looks like a regular LED.

 

[Justintoxicated 10+ year member]

i got it here. http://www.x-tremegeek.com/templates/searchdetail.asp?T1=142+0342&dept=2gd&search=2gd20&child=
there's also a waterproof one from Inova that I like, but it doesn't use Luxeons. A couple of our engineers have the Luxeon focus-able maglite replacement.

Ahh A dorcy cool //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Those drop in Luxeon mods for the maglite are pretty weak, they don't provide enough power to the LED, because they don't have enough Heatsinking since it is a plug in modual. I have a 3C Mag I run off NIMH Batteries DD to the LED, the HS is pressed into the mody of the mag, and has a raised area so as to create a nice beam. It's still adjustable but you have to turn the head alot farther because the focusing post in the stock mag is removed for the HS. I never seem to adjust it though it's best with a nice tight beam. I modified the reflector to take out any blemishes and artifacts in the beam the beam is insainly smooth and perfect now. I also finished it off with a UCL Polarized Glass lense so as to maximize output. I hate the stock crappy plastic they put on Maglites its soooooo much nicer with the UCL lense. And I finished it off by making a ring of glowpowder around the LED so that the end of the flashlight glows Aqua after using the Light for a short period of time. Makes it easier to find in the dark //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

So it is a UV LED? Not sure how to tell really without nowing anything about it.

 

[Rattlebrain 10+ year member]

Just like a black light you would buy at Spencers to make florescent colors glow. Just in a LED form. I would get a picture of it but I cant find the little Fugger right now. It looks like a regular LED.

OK I found it. Here is a picture if it helps any.

 

[MetalMaxima 10+ year member]

So if I were soldering 4 LEDs in series, with the assumption that each LED were drawing a constant 3V, I would only need ONE LM317T in order to regulate the 12 to the circut, correct?

 

[MetalMaxima 10+ year member]

bump......