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Thread: run time?

  1. #1
    mtbr member
    Reputation: hizzity's Avatar
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    run time?

    I have looked around trying to find what the equation for finding out run times is but I can't find it. anybody know it? I am building a 3 cree q5 system running at 1ah and using a 14.4 3800mah battery. I am thinking that since it is running a 1000mah and should get 3.8hrs?
    It's go time

  2. #2
    maker of trail
    Reputation: essenmeinstuff's Avatar
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    Quote Originally Posted by hizzity
    I have looked around trying to find what the equation for finding out run times is but I can't find it. anybody know it? I am building a 3 cree q5 system running at 1ah and using a 14.4 3800mah battery. I am thinking that since it is running a 1000mah and should get 3.8hrs?
    Your method is wrong, but you've come up with probably an accurate number lol.

    Unless you're running a linear regulator, calculate your LED power (LED voltage times 3 times the current in A), divide it by about 0.9 to take the efficiency of the regulator then that is the power drawn from the battery. Divide that power number by the battery voltage, and you have your actual battery current, divide this by 0.9 to take your battery discharge efficiency and you have your "drain" on the battery.

  3. #3
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    Quote Originally Posted by essenmeinstuff
    Your method is wrong, but you've come up with probably an accurate number lol.

    Unless you're running a linear regulator, calculate your LED power (LED voltage times 3 times the current in A), divide it by about 0.9 to take the efficiency of the regulator then that is the power drawn from the battery. Divide that power number by the battery voltage, and you have your actual battery current, divide this by 0.9 to take your battery discharge efficiency and you have your "drain" on the battery.
    Cool, thanks. It looks to be about 3.6hrs.
    It's go time

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