Converting 12v lights to LED

Discussion in 'The Projects Forum' started by Dozer, Mar 12, 2012.

  1. Dozer

    Thread Starter New Member

    Mar 12, 2012
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    I have an existing 12v lighting system I installed that provides lighting to the stair case leading to my house and the parking area at the top of that stair case. The 12v system bulbs are S-8 automotive style bulbs and they don’t last very long.
    The stair lights are mounted in a single gang box imbedded in concrete and the path lights are each mounted to a single gang box which is mounted on the railing around the parking area.
    I would like to convert all the 12v S-8 bulbs to LED's for bulb life but I am not up to speed on what type of voltage and current regulating circuit would be appropriate for this, I also do not know if a single regulating circuit can be made and run the LED's in parallel?
    The lights I looked at are Lumex SML-LXL99MWC-TR/5 (spec sheet attached)

    Any suggestiones are greatly appreciated.
    Kind regards,
    Matt
     
  2. #12

    Expert

    Nov 30, 2010
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    This looks like a job for www.romanblack.com

    He has 12 volt constant current, switch mode designs that are perfect for this.
    I've also heard of a "buck-puck" but haven't looked them up.

    You will need one regulator for each LED.
     
  3. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    I believe S-8 is a bulb size, not a lamp trade number. Do you really need a 5 W LED?
     
  4. gerty

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  5. #12

    Expert

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    One of my personal limitations is that I usually assume the original information given was properly researched. Bernard correctly points out that Dozer has not given enough information for us to double check his calculations on the required amount of LED power.

    Gerty has a very good idea. Not needing a regulator is always cheaper than building one.
     
  6. Dozer

    Thread Starter New Member

    Mar 12, 2012
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    All great suggestions, including proper research, but I had to get nudged on what I was doing wrong before I knew to move on and do something else wrong.
    The lights are 1156 base 18 watt 12v lamps, going to a brighter bulb is ok as these are for safety on the stairs and walkway (it is my wifes parking space and she and the kids use it, I have to park on the hill).
    The link to the prefabed automotive LED's is great, but very pricy, maybe other options are just as pricy and more time consuming?
    As far as the brightness of LED, I dont know? is 5 watt too bright, it appeared to be about 180 lumens, but I am not well versed in this area.
    So, out of simplicity, if I am using an 18 watt 12v light now and dont mind going brighter, what may an appropriate wattage for an LED?
    Assuming the 30,000 to 50,000 life of the LED's I may only have to buy these once every ten or twelve years.
    Kind regards,
    Matt
     
  7. Dozer

    Thread Starter New Member

    Mar 12, 2012
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    OK your lead has sent me down a good path...
    p.s. BA15s base, 1156 was a part number. and I have now found several options depending on the appropriate wattage.
     
  8. KJ6EAD

    Senior Member

    Apr 30, 2011
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    You might just get some strings of cheap white LED Christmas lights and modify them to run on 12VDC.
     
  9. #12

    Expert

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    I'm picking up the idea that you would need about 400 lumens to match an 1156 bulb. Check carefully to see if I am right in saying that the superbrite site might be selling fairly dim bulbs.
     
  10. Dozer

    Thread Starter New Member

    Mar 12, 2012
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    All of the LED BA15s base bulbs I find only state howmany LED's they have in them i.e. 9, 15, 24, 45, but there is no mention of light output. Are there basic rules of thumb for LED output in these types of configurations?
     
  11. #12

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    Nov 30, 2010
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    I looked up the 1156 bulb as an incandescent and it was listed as 32 candlepower. Another site said a candlepower is about some number near 12.5 lumens. That number times 32 = 400 lumens.

    The fact that 2 different sites were involved and possibly the involvement of distance from the lamp means I am guessing. However, selling lamps that have no mention of brightness or light output is a bad sign to me. Would you like to buy a rope from me? I make no mention of its length.
     
  12. Bernard

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    Aug 7, 2008
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    Might it be advantageous to compare a 1156 to a 75,000 mcd, white, 3.4-3.6V @ 30mA, 40 deg. LED, $1.49, G17255 Electronic Goldmine, in a night time test? If you had a choice of color, what would it be.
     
  13. Audioguru

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    Dec 20, 2007
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    Use millions of very dim Christmas tree LEDs. The total amount of light will be like one candle.

    A light bulb is bright because it burns a pretty big filament at thousands of degrees C.
    They are made to get hot and like to be hot.
    Bright LEDs also get hot but heat damages them so they must be cooled somehow.
     
  14. Dozer

    Thread Starter New Member

    Mar 12, 2012
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    White is what I am using. I imagine the 1156 12v bulbs I have are similar to soft white but I don’t think a whiter white will be an issue since these are safety primary and ambiance secondary.
    I looked at the 8mm ultra brite, it claims 75,000 to 90,000MCD which if my 30 second defenition of MCD look-up serves me is about 75+ watt bulb equivalent depending on dispersion. I think a test of one unit is a good idea though it will require some voltage/current regulator set-ups to use those. I also found a waterproof 45 LED light BA15s LED lamp for $4 from china that I will throw into the test since all I have to do is plug that in.
     
  15. KJ6EAD

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    I fear that if you put some nice, bright removable LED automotive bulbs out there, some car enthusiast punk will quickly steal them unless they're enclosed in some kind of theft and vandal resistant housing. :(
     
  16. Dozer

    Thread Starter New Member

    Mar 12, 2012
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    Theft wont be an issue in this application, these are the units they will be installed in, Focus Industries SL-02 and SL-07 light housings.
    [​IMG][​IMG]
     
  17. KJ6EAD

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    That's a relief. Those are nice housings.
     
  18. russpatterson

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    Feb 1, 2010
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  19. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Does the bulb go straight in or does it face down. Just for fun I converted a 1156 base to a bright LED, in line but could be mounted at rt angle- operates at 5V DC. Is present 12V power supply AC or DC. Total no of bulbs?
     
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