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Thread: Help with 12V to 5V step down converter.

  1. #1
    Who am I? HiJackZX1's Avatar
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    Help with 12V to 5V step down converter.

    I bought a 150 watt, 30amp, step down converter. Its supposed to take me from 12V to 5V. i am using this for all my hubs and many 5V based devices. My understanding is that this unit steps down the voltage by turning the extra energy into heat.

    Obviously I have to cool this thing down, so would it be ok to build an enclosure to cool the unit down? Basically it would have a fan to the right and left of it, so the air passes through the fins to cool it. Im just worried that cooling it to much will kill its function. If I cool it to much will that mess up its ability to stepdown to 5V?
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  2. #2
    Maximum Bitrate Mickz's Avatar
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    You can't over cool it with fans. Overcool would be putting it in a freezer, and then the problem would be condensation/moisture as it warmed.
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  3. #3
    Variable Bitrate
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    The only energy the device would dissipate would depend on the current it is sourcing.
    Many electronic converters just chop the 12V and then smooth it again to give the 5V required so there is little heat generated as you expect when dropping 7V@30A across a drop-down resistor.
    I would connect it up to your load first in an open position and feel how much heat it generates by feeling the heatsink.
    Are there any specs which show the Watts dissipated ?
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  4. #4
    Who am I? HiJackZX1's Avatar
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    Thanx, that all makes sence. Here are the stats listed on the website.

    Input Rage: 10 - 30 VDC
    Output: 5 VDC
    Output Current: 30A
    Size: 77*77*30(mm)

    Waterproof;
    Light compact, convenient to use and transport;
    Switching mode power supply, Non-isolated, efficiency:> 90%;
    Ambient temperature at -10 ℃ ~ 45 ℃;
    with overload / over-current / over / low voltage protection (some of the products have the protection of plus or minus reverse), stable performance.
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  5. #5
    Variable Bitrate
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    OK so 150W @ >90% efficiency means about 167W total at full-load from the 12V supply.
    This means that at full-load the converter will only need to dissipate about 16W and less if not at full-load of 30A @ 5V.
    Chances are with that large metal surface area heatsink it will only get warm to touch with normal convection cooling but give it a run to check before you stash it anywhere.
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  6. #6
    Who am I? HiJackZX1's Avatar
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    All the devices will be pulling about 21 amps. So I should be good? I could just have the fans in case. This will be tucked in a tight space.
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  7. #7
    Maximum Bitrate Mickz's Avatar
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    You should have no heat issues with a switch-mode supply at that current, case fan air should be ample and as suggested, run it loaded for about 20 minutes and verify it holds at a stable temp in its installed location.
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  8. #8
    MySQL Error soundman98's Avatar
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    i would probably put a fan right next to it, so some directed airflow is going across it, but other then that, the case options are up to you.. i might need to pick one of those up for my 5v hub..

  9. #9
    Raw Wave
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    It should only dissipate ~16W - hence less than a 21W bulb. And in that finned-case, that should not be a problem.
    It may have thermal limiting anyhow, but feeling it as comfortably warm should allay any fears.

    If it were linear, then it would dissipate up to 300W, but it isn't - its an SMPS.


    BTW - how $much & where from?

  10. #10
    Maximum Bitrate Mickz's Avatar
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