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LED lights dimming after several minutes

Discussion in 'LEDs and Optoelectronics' started by heng512, Dec 17, 2015.

  1. heng512

    heng512

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    Dec 17, 2015
    Hi, I installed an LED strip for my kitchen counter. Since I'm living in an apartment, I didn't want anything too permanent, so I decided to to power the LED strip using rechargeable batteries.

    The power specification for the LED strip is 12V DC. Since rechargeable batteries (AA) are 1.2V, I used 10 batteries. When it powers on, the LED strip will be at the regular brightness that I would expect. However, I've noticed that after several minutes, the light output would dim.

    Would using rechargeable batteries be causing this? I can go out and buy 10 regular AA to test it, but I wanted to check here first to see if anyone has an answer.
     
  2. Sadlercomfort

    Sadlercomfort Ash

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    Feb 9, 2013
    The voltage seems perfectly fine for the application.

    How long is the strip? The smd leds may be small but can consume alot of current if your running a few meters.

    I recently brought a 5m strip myself, which consumes 12v, 5A! If I used batteries I would experience the same issue your having.

    It might be more practical to use a dc adapter, rated properly. But you need to know the current draw of your strip first.
     
    Martaine2005 and Arouse1973 like this.
  3. Sadlercomfort

    Sadlercomfort Ash

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    Feb 9, 2013
    If you know how many leds are in the strip you could find out the current draw that way.

    Let's say 100 leds at 20mA:
    100×0.02=2A

    Then a 12V, 2A adapter would be suitable. It's a more permanent than batteries but at least they won't discharge after a few hours.
     
    Martaine2005 and hevans1944 like this.
  4. heng512

    heng512

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    Dec 17, 2015
  5. Sadlercomfort

    Sadlercomfort Ash

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    Feb 9, 2013
    Same led type as I have! Those 300 leds consume 2A.

    So a 12V, 2A adapter or higher current is needed.


    I think your batteries setup might discharge about every 10 hours. Depending on there current rating.

    Still I would recommend a DC Adapter, these are really common 12v, 2A so you might find one knocking around the house.
     
  6. heng512

    heng512

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    Dec 17, 2015
    Great, thanks for the information. I guess for regular used lights that are one for a while should probably be plugged in.
     
  7. Sadlercomfort

    Sadlercomfort Ash

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    Feb 9, 2013
    No problem ;)
     
    Martaine2005 likes this.
  8. Martaine2005

    Martaine2005

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    May 12, 2015
    Sorry can you explain that again?
    Ash (sadlercomfort) gave a very nice explanation of what power supply to use.
    You can go a little further and buy/use a supply that has a higher Amperage output. Like a 3Amp to keep it cooler.

    Martin
     
  9. Sadlercomfort

    Sadlercomfort Ash

    424
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    Feb 9, 2013
    Frequently used lights :)

    Yeah, a higher rated adapter would run comfortably without being stressed.
     
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