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Help choosing power source

Discussion in 'LEDs and Optoelectronics' started by Pharaday, Aug 18, 2020.

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  1. Pharaday

    Pharaday

    114
    3
    Jan 18, 2016
    Ok guys, today I wanna build a light out of 24 of those backlight LEDs from TVs (LM41-00121E could not find datasheet right away, here is ebay link: https://www.ebay.com/itm/SAMSUNG-UN...0121E-LM41-00121F-39667A-39668A-/333065226733 ).

    I'd like the light to have a power plug so that you can plug two appliances into that. I was going to run one pwer cable into the case and split it so that it powers an appropriate DC converter and the wall plugs. But the only converter I have that comes close to powering those is a 32V 940mA supply and it only powers half the required lights.

    So I was going to put two of those supplies in the case for power. Then I thought about the two appliances the plug may power along with the two supplies that would all draw power from one cord. Surely I have a watts limit to the things I can plug in there, right? I'm sure this is a simple formula plug and chug, but could yall speed me up? lol do I need to just cram a power strip in there?

    I could put a sufficiently fat cable. I have plenty of wall warts but.... what would you guys say is the best way to power this project? It's gotta be done, days of work and like $100 of supplies is invested in this. Please gimme a factor of safety here as well, this is a birthday present for my younger sister. No need to bust out the calculator, a ballpark limit will do, but ballpark also me up a good factor of safety like 2 or so. Again I appreciate the help!
     
  2. Pharaday

    Pharaday

    114
    3
    Jan 18, 2016
    Also, those printer 32V supplies are the highest voltage ones I have. I feel like a ~40V one would do it, but I'd prefer not to have to wait on shipping to order one I'm not sure will work. I have all common voltage/amp supplies below 32V
     
  3. Pharaday

    Pharaday

    114
    3
    Jan 18, 2016
    I donno guys do these things take too much jefferson damn power? I'm now thinking of using mortal LEDs for my unnecessarily lit coffee tables like a common hobo. These things are just so near impossible to blow and freakishly bright. Weigh that against 40V to power 24 LEDs, man. I can still look at this as a learning experience. Continue with your analysis, please. What considerations will I have with just 5mm LEDs that might get overlooked? OP: Isn't FOS generally a structures thing? But I get what you were saying....
     
  4. Pharaday

    Pharaday

    114
    3
    Jan 18, 2016
    ok, OP, I alone hold the answers you seek. What you're gonna wanna do is take mains power from your house and simply convert it into DC via a common AC/\/DC converter. Use a fuse when working with mains. If that's not enough power, simply use one of your transformers. Your only other option is to find that 40V adapter you have somewhere and pray it's enough. Best of luck! All our hopes and dreams go with you!
     
  5. Martaine2005

    Martaine2005

    2,909
    796
    May 12, 2015
    Why did you buy TV backlights?
    Why not a 12V 5 meter strip with AC to DC controller?.

    To answer your question, power strips or extension cords have a max rating. This is based on the cable size and also that the cable is not coiled or rolled up.
    0.75mm, 1.00mm, 1.5mm and 2.5mm for example all work on mains voltage. They all have different maximum current ratings.
    It is down to you to work out what appliances will be connected and what the total load/current plus some overhead will be. Then use the appropriate gauge cable.

    So Volts x Amps = Watts.

    So grab that calculator.

    Martin
     
  6. Pharaday

    Pharaday

    114
    3
    Jan 18, 2016
    Right on! Thanks, both of you! I somehow didn't think it could be that simple. I got it working with a huge printer AC adapter. To answer your question, those backlights are free. I harvest untold numbers of them from broken LED TVs. I did buy one of those 12V light strips to check them out. They have their uses, but for a few more volts I get like 3 times the brightness from those backlight LED strips. I have plenty of volts, I'm after that blinding brilliance! I'll prolly make one using each light source. I'll send yall some pics after I sand etc.

    Thanks again!
     
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