ssc p7 cooling issue- Mtbr.com
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  1. #1
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    ssc p7 cooling issue

    Hi! I am designing a light for my mtb using https://www.dealextreme.com/details.dx/sku.22567.

    Has anyone any idea how to handle the heat? I am using a 2.8A driver. I am afraid that the heat will override the absoulte maximum in the specification.

    Cheers Daniel

  2. #2
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    How are you planning to use the light body, in it's original form or just the head ? The light as-is has quite a bit of surface area, and with the air flow of riding you'd probably be fine at 2.8a. I have the MTE 2 mode P7 C bin flashlight and it runs at a full 3a since it's direct drive. Never seen it to have any overheating issues when moving.

    On the other hand, I'm currently in the latter stages of a dual P7 D bin based on achesalot design and running a pot dimmable driver up to 2.75a - it gets HOT, too hot. I haven't cut and installed the heatsink materials on the main body yet, but I'm already anticipating the need to sink some heat into the mount system and even to the bars, so the mount will need to be aluminum and well attached to the light body.

  3. #3
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    Yes, I am planning to use the flashlight as it is. Just added wires to external Li-Ion battery pack togheter with the driver.

    It get so hot that is smells burned ;-) . But I have not made any measurements of the temperature.

    DR

  4. #4
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    I think your light has a poor thermal path for the LED. Disassemble and apply thermal joint compound to all the mating surfaces from the LED to the shell and see if the LED will run cooler.

  5. #5
    I like bloody ankles
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    Quote Originally Posted by Vancbiker
    I think your light has a poor thermal path for the LED. Disassemble and apply thermal joint compound to all the mating surfaces from the LED to the shell and see if the LED will run cooler.
    Good call Vancbiker. I didn't mention that I had disassembled my light, added thermal compound under the star, cleaned up all of the ground path contact points, and added dielectric grease to the threads on the body. Prior to doing this, my light flickered even when sitting still, now it's rock steady.

  6. #6
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    The termal path is ok and there is thermal compond on the LED base plate. The flash light structure get really hot, does not this means that the thermal path is functional?

    I will do some measurements and post a reply with the result.

    Cheers DR

  7. #7
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    I have made som measurements a hot summer day in Sweden. It seems that the temperature is stable after 20 min burning time. It ends up at 85 degrees Celsius. I can accept it.

    Thanks for all advices!

    Cheers Daniel
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  8. #8
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    I have made som measurements a hot summer day in Sweden. It seems that the temperature is stable after 20 min burning time. It ends up at 85 degrees Celsius. I can accept it.

    Thanks for all advices!

    Cheers Daniel

  9. #9
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    I have measured it to 86 degrees Celsius and it seems ok. Thanks for all advices
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  10. #10
    I like bloody ankles
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    what did you use to get that thermal image ? that's good stuff...

  11. #11
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    yikes ...smoking hot. Just think of how cooked that led is getting; it runs much hotter! From my experience, if you can't hold the enclosure it's getting to hot for making optimal Lumens (as lumen output drops way off w/ increased temp)

    Cool thermals, wish I had one of those!

  12. #12
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    Quote Originally Posted by DanneRe
    I have measured it to 86 degrees Celsius and it seems ok. Thanks for all advices
    If you measure the temp at the die, 86 C is ok, as that is around the test temp Cree uses, but I'll bet 86 C at the surface means a much higher temp at the die. I'll bet you burn out the led in less than 10,000 hours...

    ...course, 10,000 hours is equal to at least 3,000 to 5,000 night rides. Not a bad lifetime...
    I know a lot about cars. I can look at a car's headlights and tell you exactly which way it's coming.
    Mitch Hedberg

  13. #13
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    do you guys just use these to light your workbench?

    cause if you're moving 10mph at 90f, they're completely cool to the touch.

    measuring it while it's sitting still doesn't tell you much.

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