Ideas......needed for freezer circulation fan frigoboat system

[CYQK]

So i have a Frigoboat system it is used as a freezer
Tried to hook up a fan to circulate air in the box.Did testing and it greatly improved the performance,have state of the art insulation
Had the brochure from when i purchased the unit in 2013,took that long to finish my project. Started around the same time as the 757 pilot was doing his boat,for those of you who remember his awesome posts! Where is he miss those posts!!
The sheet explained to install a jumper and hook up the power wires at locations on the thermostat/switch
Well not so for my unit..powered up and it took out the merlin speed controller
Talked to Maureen at frigoboat and she said there is no way to hook up a fan to my existing unit

My question for the talented ones here is...

I have a battery powered one inside now that works ok but the problem is that it runs continously

What have you come up with that has a controller of some sort that will control the fan

Thks

 

[jviss]

What would you like to use to control the fan? Perhaps temperature? If so, you can get an Inkbird thermostatic controller for around $15.

 

[Project_Mayhem]

A solid state relay might allow you to turn on a fan when the compressor turns on as it only draws 15-35mah. Are you trying to move cool air away from the cold plate or simply circulate air around the freezer box? If the latter, does it really need to turn off?

 

[CYQK]

Right now i have the fan set to direct air right on the cold plate and it seems to work the best
Yes a relay would work
Asked the Lady from Frigoboat and she had no suggestions as to where i could get the power from??

 

[Project_Mayhem]

There's a difference between a mechanical and solid state relay. An SSR doesn't draw as much power to trigger and theres no voltage spike on the electrical line. There's also switche modules out there that detect vibration or as @jviss suggested, temperature. The vibration sensor could be placed on the compressor to detect when it's running and you wont have to mess with the freezer circuitry.

In the three examples I mentioned, you would get power from your boat's electrical system. You can use the same point that the freezer gets its power from. Personally, I would go for a solid state relay, followed by the vibration sensor. All options are very inexpensive and boils down to reliability and preference.

Does leaving this fan on all the time do any harm?

 

[Straycat22296]

I use a 4"x4" computer fan. It has been installed for at least 10+ years.
I installed SS bolts through the 4 mounting holes with suction cups on the ends. It attaches to the side of the ice box near the cold plate.
It is set up with an aproximately 1 1/2" gap between the fan and the wall to allow air flow. I had to do some testing to make it work.
It is wired directly to 12 volt power through a push button switch.
Yes, it is always on if not turned off at the switch but the power requirements are small and it really helps.