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Thread: Hot video tx, attach heatsink/fan?

  1. #1
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    Hot video tx, attach heatsink/fan?

    My video tx pulls 800mW, and can get VERY hot (even too hot to hold). Before I fulfill my project and start flying I want to make sure it won't cook before the flight's over, I know that on a plane it'll get airflow but in the heat of summer would that even be enough? I have a list of a few things that I want you guys to check out and tell me if they might do the trick:
    -http://www.ebay.com/itm/131014795047...%3AMEBIDX%3AIT
    -http://www.ebay.com/itm/271462972707...%3AMEBIDX%3AIT

    If there are any suggestions in terms of heatsinks, the surface area on my tx is 23mm x 31mm

  2. #2
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    Quote Originally Posted by K-Note72 View Post
    My video tx pulls 800mW, and can get VERY hot (even too hot to hold). Before I fulfill my project and start flying I want to make sure it won't cook before the flight's over, I know that on a plane it'll get airflow but in the heat of summer would that even be enough? I have a list of a few things that I want you guys to check out and tell me if they might do the trick:
    -http://www.ebay.com/itm/131014795047...%3AMEBIDX%3AIT
    -http://www.ebay.com/itm/271462972707...%3AMEBIDX%3AIT

    If there are any suggestions in terms of heatsinks, the surface area on my tx is 23mm x 31mm

    I used a TO-220 heatsink from radio shack (PN 276-1368) and a tiny dab of JB weld to hold it on.

    In before 10 other people say it's not necessary.
    "If it breaks, you get to keep both pieces"

  3. #3
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    Quote Originally Posted by Airborne View Post
    I used a TO-220 heatsink from radio shack (PN 276-1368) and a tiny dab of JB weld to hold it on.

    In before 10 other people say it's not necessary.
    Does JB Weld transfer heat? I was thinking of using thermal paste, turning it on to heat up a few times so the heat can set it

  4. #4
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    Quote Originally Posted by K-Note72 View Post
    Does JB Weld transfer heat? I was thinking of using thermal paste, turning it on to heat up a few times so the heat can set it
    It worked well enough for this application. The heatsink is the same temperature as the case where it is mounted, so it is transferring heat..

    There is nothing wrong with using thermal adhesive if you have it. You might even stand a better chance at being able to remove the heatsink later on. It is never coming off if you use Jeb Weld.
    "If it breaks, you get to keep both pieces"

  5. #5
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    You can also buy heatsinks with thermal glue pre-applied, loads on ebay of all different size. I just use small copper sinks (they aren't more than 6mm in height) and just stick them ontop.

  6. #6
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    Quote Originally Posted by londonguy View Post
    You can also buy heatsinks with thermal glue pre-applied, loads on ebay of all different size. I just use small copper sinks (they aren't more than 6mm in height) and just stick them ontop.
    I just figured these heatsinks and some cpu thermal paste should work

  7. #7
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    Well I jumped on those parts and have them on order, meanwhile I did a little test (well 2 tests in one actually). I had my tx powered on and idle and set on it a 40mm fan, 1.08 watts (low airflow really). I got an excess of 1 hour of power (no signal feed), and the whole time the tx only got a little over lukewarm. Funny how just a tiny bit of airflow made all the difference, so hopefully with the heatsinks alone I can keep it cool in flight. Next time I'll do the same stopwatch test of battery life again, except I'll actually have a video feed transmitting.

    Seeing as how a 2200mah powers the tx for an hour, I could get away with 1300-1500mah for a decent flight right? Don't see the flight battery lasting that long anyways
    Last edited by K-Note72; 22nd June 2014 at 11:51 PM.

  8. #8
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    All gear fully charged and fully hooked up, I clocked the life with the given 2200mah for the tx and 5000mah for rx. I got to 2 hours and 17 minutes, only because my monitor's battery started dying.

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