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How do I drive a Peltier Cooling Plate with USB power? Answered

I just ordered some of these 20mm x 20mm Peltier Cooling Plates and would like to power them with a USB hub.

Their rated at max of 4 amps and a max 3.8 volts and I know that generally USB is 5V and 500mA.

So I know I need to just reduce the voltage, but I'm not sure how to accomplish this.

I think I could drive them at 3.5V and still be okay, Not sure if I need a voltage regulator or if just resistors would do the trick.

Thank you

Kurt

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Downunder35mBest Answer (author)2015-05-13

You don't drive a peltier element on a USB connection, period.

Run them at their rated current with a suitable power supply.
Even a high power USB port is rated to a max of 2A, so your elements won't do much as they can't get the power they need.

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mpilchfamily (author)2015-05-13

Nothing you can do to adequately power that particular peltier off USB. If you want to play around with a peltier on USB then get one made for it. This is a good option for about $20.

http://www.thinkgeek.com/product/96b3/?itm=customl...

If you want to use the one you have then find an old PC PSU. Use the 3.3V rail from it to power the Peltier and your good to go.

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Wired_Mist (author)mpilchfamily2015-05-13

+1

at 500ma that cooler Mpilch linked to may not do too much, but it's the best your going to get for Usb

If you do build your own solution I would suggest you use a decent 5V power adapter and run it through a lm317 in *constant current mode*. Use the lm317 to limit the current to 3-4 Amps. The regulator has a natural 1.25V drop across it, bringing you down to 3.75v.

I have a few old hubs and routers that just so happen to have a 5v, 3A output. Perhaps you have something similar sitting in a box of cables !

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KurtRoesener (author)Wired_Mist2015-05-13

Good point, I just might, I tend to save just about everything ;)

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user

Okay, thanks for the link!

I do have extra PS units around, I was just trying to avoid extra outlets being taken up.

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