I am looking for a little help as I am trying to make a small Peltier cooler and having a little trouble. FYI I have very little idea on what I am doing just got an idea off of youtube and gave it a try so please be patient as I am totally ignorant on this topic. So....I purchased the following products.



These are a premade Peltier cooler: parameter: Working voltage: 12V Maximum power: 72W Maximum current: 4-6A Product size: 11810068MM The package includes: 1*DIY semiconductor air cooling kit

Power supply above12V 7A

That was all copy and paste and have no idea what all of that really means. Then I purchased a 12v accessory plug

input 12v Output max 5amp

I soldered all of the positive wires together and did the same for the negative. Plugged it in and the unit seems to work. Fans blow and heat exchange seems to happen. The issue is that it happens at such a slow rate that it doesnt seem right. I have been running it in a small cooler for about an hour but there has been no change in temperature of the cooler. I have vented the heated air to the exterior of the cooler. Is it under powered?

Background. Why am I trying this???? As a part time gig I own vending machines. I also live in south Florida (Naples). It gets hot and my chocolate candy doesnt seem to like the heat. I was hoping to build this unit and keep it plugged in to at least keep the chocolate from melting. It just has to stay at about 70 degrees. I dont need it to be cold just cool at best. Please help.


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    \$\begingroup\$ Can you include a photo or diagram of your setup? You say that you are venting the warm air to the exterior, however it is unclear how this is accomplished. You need the hot end installed on the outside of the cooler and only have the cold side/heatsink protruding into the cooler with a good seal around whatever opening you insert this through. \$\endgroup\$
    – Ben Watson
    Commented Oct 3, 2021 at 18:19
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    \$\begingroup\$ For a practical application, forget Peltier and try a 12V compressor refrigeration unit. (Or 120V) \$\endgroup\$
    – user16324
    Commented Oct 3, 2021 at 19:36
  • \$\begingroup\$ So I purchased this cooler walmart.com/ip/Igloo-38-qt-Ice-Chest-Rolling-Cooler-Blue/… cut a hole in the side and then attached the fan that expells the heat to that hole. The whole unit still sits in the cooler but the hot air is blown out of the hole. I just dont have my little project with me right now or I would send a pic. \$\endgroup\$
    – Johng7769
    Commented Oct 3, 2021 at 22:41
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    \$\begingroup\$ Putting the heatsink into the cooler is probably leaking more heat back into the cooler than it pumps out. Instead you should cut the hole such that the cold side is inside the cooler and the hot side is entirely outside of the cooler (and insulated as best as possible from the cold side). TECs do not move a lot of heat, so you must use what they do move efficiently. \$\endgroup\$ Commented Oct 4, 2021 at 2:47

1 Answer 1


A Peltier cannot generate a lot of 'cold'. You might be able to get a 20 °C difference from ambient if you do have a good fan maintaining the 'hot' side close to ambient.

It seems the unit you have is a 2-stage cooler. This is probably not best for your application, in that while it may be able to generate a cooler temperature, the amount of cooling (i.e. heat it can absorb at that temperature) is low. You should use a single-stage Peltier for this.

  • \$\begingroup\$ Are you able to point me to what you think would work best for my application? \$\endgroup\$
    – Johng7769
    Commented Oct 3, 2021 at 22:38

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