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LED Lighting project

Discussion in 'LEDs and Optoelectronics' started by scutty247, Feb 12, 2013.

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  1. scutty247

    scutty247

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    Feb 12, 2013
    Hello everyone,

    I appreciate an LED lighting project is probably not very original on here but thought I'd start a fresh thread.

    I am currently working on a medical lighting system for developing countries. It will be solar charged and use NI-MH rechargeable AA batteries and a commercial 12V LED cluster.

    I have the LED cluster and they are 12V and 0.24 Watts each. I would like to use 12 of these as that means a good quality light but it could be slightly less if needs be. Therefore its a 12V strip and 12 would need 2.88 Watts.

    My questions are:

    1) How many batteries would i need to make it work?
    2) How long would I get out of the batteries per charge (ideally I would like 9 hours but 6 is acceptable)?
    3) How powerful a solar panel would I need to charge it in 12 hours?

    Many thanks for your time. If anyone does any maths please go easy on me as I'm a maths biff!
     
  2. BobK

    BobK

    7,682
    1,686
    Jan 5, 2010
    2.88 Watts at 12V is 240ma. An AA size NiMH is likely around 2000maH. So you would get about 8 hours out of a battery made up of 10 cells in series to get your 12V.

    The charge them in 12 hours you would need a charge rate of 2000/12 or 166ma ideally, but there are losses, so more like 200ma at a bit over 12V (say 15), or about a 3W panel.

    Bob
     
  3. scutty247

    scutty247

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    0
    Feb 12, 2013
    Excellent, thank you. This totally backs up what I have been told but just wanted to confirm.

    Thank you very much.
     
  4. scutty247

    scutty247

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    Feb 12, 2013
    Just one more question. If I needed to connect 3 of these lights to one solar panel would i simply triple the power output of the panel? So a 9W panel??
     
  5. BobK

    BobK

    7,682
    1,686
    Jan 5, 2010
    Yep. Power does add that way.


    Bob
     
  6. scutty247

    scutty247

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    0
    Feb 12, 2013
    Awesome! Thanks again
     
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