Thermoelectric Device, how to test one

Discussion in 'General Electronics Chat' started by Gdrumm, Oct 7, 2016.

  1. Gdrumm

    Thread Starter Distinguished Member

    Aug 29, 2008
    684
    36
    A wine cooler stopped working, and I took the back off, and found the boards.
    I found and unplugged one lead of a thermoelectric device that converts heat to cool, or vice versa.
    When I did, things started lighting up, as though it was turned on (but it wasn't cooling)..

    I tested the ohms of the device, and it started at about 38, and began to drop slowly.
    When I hooked it up to 12v, all I got was a repeating beep.

    When I hooked the Pos. wire to Pos. on my meter, and neg. to neg., the meter also beeped (as though a direct short).

    Is the device bad? (I found some on ebay pretty cheap, and I'm pretty sure I can put it all back together correctly.)

    The wine coolers sell for anywhere from $50.00 up to $500.00, so if I can get it working, that would be cool.
    (pun intended)
    Thanks
    Gary
     
  2. wayneh

    Expert

    Sep 9, 2010
    12,086
    3,024
    The TEC should show a DC resistance of about 1 ohm. A value of 38 is too high for the module. What beeped on 12v?

    In my opinion the TEC is possibly ok but places too great a load on the power supply. That's where the problem is. But are you saying that everything works fine as long as the TEC is not connected?
     
  3. MrChips

    Moderator

    Oct 2, 2009
    12,414
    3,353
    Testing a TEC is simple.
    First of all, you want to derate the unit. For example, if the TEC is a 12V, 12W unit, derate it to 6V, 3W.
    Use a fixed 6-9V power supply (or a current limited supply) and connect to the two leads of the TEC.
    Very quickly (within a matter of seconds) one side should feel cool while the other side runs hot. Don't run this test for more than 10-20 seconds to avoid damaging the TEC.
     
  4. wayneh

    Expert

    Sep 9, 2010
    12,086
    3,024
    A 5V supply from an old computer PSU works nicely for testing a 12V module. As noted, just a few seconds to feel cold on one side and hot on the other.
     
  5. Gdrumm

    Thread Starter Distinguished Member

    Aug 29, 2008
    684
    36
    I have some old PC Power Supplys, and should be able to test it this weekend.
    Thanks
     
  6. wayneh

    Expert

    Sep 9, 2010
    12,086
    3,024
    If you haven't seen it yet, you may find this thread useful.
     
Loading...