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  1. #1
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    Dumb Driver Question/s

    Running 2 strings of XPEs with 1000 mA Buckpuck.

    So 500 per string. Simple math.

    Been thinking about putting two 1000 mA Buckpucks in housing and running each string at 1000 mA.

    Could turn one of the 2 strings off with switch and cut lumens back by half. Still pushing 1000 mA through the powered string though. Lots of heat and decreased efficiency........

    So decided to wire 2, 1000 mA buckpucks parallel. Multimeter went from 1000 mA to 2000 mA. No magic blue smoke.

    Could run two parallel strings at 1000 mA each using the 2 parallel buckpucks. Could turn one buckpuck off with switch and the parallel strings would both be on seeing 500 mA each. Less heat and better efficiency.

    So what is the downside, problem, reasons that this should not be done?

  2. #2

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    been wondering the same thing. I have 2-700ma buckpucks that I wanted to drive 2 mc-e's with. In my mind it should work fine but I haven't dared to try it.

  3. #3
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    I am bored waiting for the XPGs to come out. Melted a Fatman and an XPE earlier tonight.

  4. #4
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    Oh well, only another month to wait for the xpg!

    http://www.cpfmarketplace.com/mp/sho...d.php?t=198575

    (28th September possibly)

  5. #5
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    How did you manage to melt a boos driver?

  6. #6
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    Texas, unless you verify that each string runs the same (or very very close) voltage under load, it would be better to run two separate buckpuck circuits. This many leds run in a chain and then split probably isn't sharing the current to well.

    Better safe than sorry, especially since ur already running them hard, and gets worse when you throw heat into the mix. My 2C.

    ~C

  7. #7
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    I think the thought is, if they are on the same thermal path (ie same surface) then you are normally ok,

    You can also put a resistor between strings to ensure that it doesn't go into runaway. Not sure what that would do to efficiency though, but I believe the resistor would only come into play if something went wrong.

    Now everybody else let me know how wrong I am

  8. #8

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    well, that's enough to scare me away from doing it. I own 2 700ma buckpucks and my wish was to have a switch to turn one off like odtexas mentioned and then have the one remaining be dimmable. I had this fear, though, that if the drivers weren't matched (ie, I had one side dimmed when both are on) then it would be unhealthy for the drivers. Just trying to make my cheap buckpucks I already own do what a better driver would have done in the first place. :-)

  9. #9
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    Zen - Wanted to see if the Fatman truly could only handle 12V input. Hooked up an 11.1 charged to 12.3. Pop it goes........... Do not even think about exceeding 12V on the Fatman.
    XPE was being DD.
    Thanks for the replies. I was more concerned about feedback to the "Off" driver. Buck pucks are tough with open circuit and load protection.
    Going to try running a 1000 and a 700 to get 850 per string. Strings are long enough that any variation should balance out I hope. The 700 is on order so it will be a bit before I know the results..... Plus I am waiting on these awesome new battery holders from sdnative.
    T

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