LED type head light for car, is this possible?

Discussion in 'The Projects Forum' started by kchan, Jul 1, 2007.

  1. kchan

    Thread Starter Member

    May 14, 2004
    12
    0
    hey guys, im wondering if the super bright LED can be use a an head light for cars ? maybe 10 or 20 LED's?

    if anyone knows how, im kinda interested coz ordinary halogen (100 - 150w)wont last long and it melts the plastic connector
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    If you can keep the junctions from overheating, it is probably possible. There are state and federal regulations aout headlamps that may prevent you from actually using such illumination. I would want to be awfully sure about the equivalence of illumination and reliability before actually using LED headlamps.
     
  3. kchan

    Thread Starter Member

    May 14, 2004
    12
    0
    hello sir, i the only possible way i think for it not to overheat is changing the bulb to a lower wattage but it has a poor light.

    im not sure about regulations in headlamps but ive seen a few headlights already that uses LED, maybe 2 or 3..

    and maybe if there is a law about it, they wont allow to use those type of headlights (i forgot the name) the one that uses ballast and electronic type, and it goes around 6000 watts. thats a cool one but very expensive for me
     
  4. mrmeval

    Distinguished Member

    Jun 30, 2006
    833
    2
    It will not give nearly enough light yet. A 5W LED can give about 65 lumens.
    Contrast this with 1550 lumens ±15% for a H1 Halogen and you'd need
    23 of them X 2 so about 46-50 of those painfully expensive chips plus the heat sinks, a pretty massive current regulator and something to focus the light where it needs to go.
    Look at HID lighting. It' s far more efficient than filament and approaches florescent
    lamps with a stunning capacity for high intensity light.
    This has some links to discharge lamps, there is another link to automobile HID lights
    http://members.misty.com/don/contxe.html
     
  5. kchan

    Thread Starter Member

    May 14, 2004
    12
    0
    ok sir, thx for the informations. well thats sad, anyways can u guys teach me how to wire a super bright LED.

    i need to wire 4 pcs of them as a light for my PSU. (i can get a source of 12V, i think thats 10A from that same PSU or 5V but i think its 30A)

    thanks again
     
  6. Gadget

    Distinguished Member

    Jan 10, 2006
    613
    0
    The other thing about super bright LED's are that they are nearly impossible to look into. I would hate to meet an oncoming car that might be using them.... kinda like looking directly into a laser....
     
  7. kchan

    Thread Starter Member

    May 14, 2004
    12
    0
    ok thank u guys about the replies.

    i hope someone can teach me how to wire a 4 pcs led direct to a PSU 12v (or same as where the PC fan molex connector is connected)
     
  8. cumesoftware

    Senior Member

    Apr 27, 2007
    1,330
    10
    I can, if you wish.
     
  9. kchan

    Thread Starter Member

    May 14, 2004
    12
    0
    cume pls :>

    heres what i remember but i dunno if its gonna work

    series connect D1, D2, D3, D4 and a 270k 1/4 watt resistor. is it correct sir?

    how can i calculate the resistor i need (for future LED projects ^^)
     
  10. kchan

    Thread Starter Member

    May 14, 2004
    12
    0
    hmm, no one wants to share?
     
  11. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
  12. kchan

    Thread Starter Member

    May 14, 2004
    12
    0
    ty sir. nice site
     
  13. cumesoftware

    Senior Member

    Apr 27, 2007
    1,330
    10
    Sorry, did not saw that. But is is simple. You will need to know that is the voltage drop for an individual LED for a given current. It is better to have a voltage/current curve to get this information. Then you use the formula:
    Rs = (Vsupply - 4 x Vled) / Iled

    Rs is the series resistor resistance, Vsupply is the supply voltage, Vled is the voltage drop for each led and Iled is the current across the LED, which is the same across the series. If you are using white LEDs for an automotive application, I would expect a voltage drop from 3V to 4V, so I yould advice you to use series of two LEDs (since voltage will vary greatly, and can achieve 18V). You can use the two series of two LEDs in paralel. You can even use a single resistor for both series, although some others might think that this is prejudicial to the LEDs (I think it might, but in the remote case of one series of LEDs being interrupted). If you use the same resistor consider the currnt needed for the association equal to the double of the current across each LED, or:
    Rs = (Vsupply - 2 x Vled) / (2 x Iled)
     
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