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IR led light powered by car battery.

Discussion in 'LEDs and Optoelectronics' started by johnpuppa, Apr 20, 2017.

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  1. johnpuppa


    Apr 20, 2017

    I'm trying to build a small project using arduino and I would like to control a 12V lamp through a mosfet.
    As a power source for the lamp I was thinking of a 12V car battery.
    The lamp I'm planning to use is this:
    From my analysis, since a small car battery has around 60A, and leds drag as much current as they can, I don't think I can directly attach the battery to the lamp. Am I right?

    If I want to limit the current to a 2A I would need a 6ohm resistor as 12/6 =2A. However 2A * 12V is quite a lot of dissipation... and I would need a a 24W resistor to be safe.. Am I right with this analysis??
    Am I better off considering a different type of battery?

  2. KMoffett


    Jan 21, 2009
    The lamp is spec'd at 12VDC/15W. So it will only draw 1.25A. It has internal current limiting. "Generally" when LEDs are spec's as a specific voltage, like 12VDC, they have internal limiting.

    Last edited: Apr 20, 2017
    73's de Edd likes this.
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