Background of the project:

I am doing my own DIY Keezer (keg freezer) which basically turns a chest freezer into a fridge that will hold kegs with the assistance of a temperature controller. The temperature controller plugs into the wall, the freezer plugs into that, and the temperature controller has a thermal sensor that goes into the freezer.

When building this Keezer, I am adding a riser in between the top freezer area and the lid (which you take off) and install all of my tap handles and gas lines, which essentially creates a large open pocket at the top of the freezer. This dead spot creates a warm climate at the top, which apparently varies depending on the freezer size and who was building it. You can overcome this feat by adding a fan to circulate the air.

Just an FYI, the desired temp will stay around the desired 38° Fahrenheit, it will never truly "Freeze".

I want to use a USB fan. I would like to install a power grommet through the riser, with the plug-in being on the inside of the freezer. The USB fan has a controller on it as well.

So to my question:

Using the products below, will the freezer being at 38° Fahrenheit, cause any negative experiences?
https://www.amazon.com/gp/product/B07PPVM1P5/ref=ox_sc_saved_title_1?smid=A1S0CF6D9DSSI6&psc=1 https://www.amazon.com/gp/product/B07V5LJ5L2/ref=ox_sc_saved_title_1?smid=A1AV40UDU1XL8S&psc=1

  • 2
    \$\begingroup\$ Please provide links to the manufacturer's datasheet for all of the components you are considering, not a link to the vendor page. If you can get a datasheet then you can't be sure about anything. Also, please clarify what you mean by "plug-in". What kind of power are you trying to pass through the wall of the freezer? \$\endgroup\$ Jan 14, 2022 at 12:29
  • \$\begingroup\$ Plug-in.. fan plugs into the outlet via usb. The opposite side of the USB oulet (which will be on the outside of the freezer) has a 3 prong AC plug that will connect to a power strip. \$\endgroup\$
    – MrJustin
    Jan 14, 2022 at 13:12
  • \$\begingroup\$ definitely ... 38° F may not be cold enough for some people \$\endgroup\$
    – jsotola
    Jan 14, 2022 at 17:51
  • \$\begingroup\$ I’m voting to close this question because this question is not about electronic design \$\endgroup\$
    – Voltage Spike
    Feb 1, 2022 at 18:35
  • \$\begingroup\$ thanks, I already have the answer, but do whatever you feel like you need to. \$\endgroup\$
    – MrJustin
    Feb 2, 2022 at 19:29

1 Answer 1


Condensation forming on/inside the controller module can cause issues. It's better to keep that outside of the fridge, so only the fan is on the inside and all the other electronics are outside.

This is especially true for a mains power AC socket and usb power supply like you shown. At the very least it would have to be gfci and condensation would be a pita.

The fan likely will not have issues running at 38 degrees. A quick Google search of DC fans shows most operate down until 14° F/-10° C.

But unless you are going to actually use the speed setting on that module often, just buy a freezer rated fan and power it directly. Less headache. A 12V fan ran at 5V will be much quieter too while still providing some airflow. Otherwise just use 12V power.

Ideally you could buy a 120/240V AC freezer fan and wire it directly into the freezers power so no need for external power adapters.

  • \$\begingroup\$ I did not figure condensation would be too big of an issue to do the USB plugs in my car operate at cold temperatures. Just was not sure about prolonged usage. I do want to use the fan controlled settings, as why I picked that one. \$\endgroup\$
    – MrJustin
    Jan 14, 2022 at 13:16
  • \$\begingroup\$ @mrjustin a car is not as air tight or insulated as a fridge. If you actually will use the controller, cut the cable and extend it through the fridge opening so the controller ane power is on the outside. \$\endgroup\$
    – Passerby
    Jan 14, 2022 at 14:22
  • 1
    \$\begingroup\$ Ok, I'll just cut it, run it through, and splice it back together. \$\endgroup\$
    – MrJustin
    Jan 14, 2022 at 16:14

Not the answer you're looking for? Browse other questions tagged or ask your own question.