Defrosting fridge evaporator plate using a timer?

[Tim Good]

In hot climates my evaporator plate get frosted. Has anyone considered adding a 12v timer on the circuit to turn the fridge off for an hour or so at night so it defrosts?

I’ve alteady put a drain hole in the bottom with an upward loop.

I suppose my question would be... do there compressors like to be turned off mid cycle? I.e if the fridge was running at 3am and my time cut the 12v to it, would it have a paddy?

 

[Skipper_Christoph]

AFAIK a normal thermostat would do just the same (turn off power supply to the compressor when chosen temperature is reached).
Therefore should be no problem.

 

[cegri]

I've done it. Works perfect.

I had tried different types / placing / setting of thermostats, without success. (I don't claim it can't be done.)

Timer turns off for 3 hours every night.

Should not be a a problem on the compressor. It's no different than the thermostat shutting it down.

 

[GHA]

AFAIK a normal thermostat would do just the same (turn off power supply to the compressor when chosen temperature is reached).

Not quite, depending on setup of course. The common Danfoss BD35 BD50 Compressors have a seperate electronic controller which monitor the thermostat (and can alter compressor RPM based on current going through the thermostat) .

Though the controller will cycle power to the compressor if voltage gets to low, so probably no problem just turning off the power to the whole unit but bypassing the thermostat would be a prettier way to go.

My thermostat is an arduino soon to be an ESP32 so will all be programmed in
https://easyeda.com/editor#id=|67a276ef2ec34fcd83171afdf3a7a63f|87596b64f5e3456c93be7c49d5d8b3f3

 

[PaulRainbow]

Though the controller will cycle power to the compressor if voltage gets to low, so probably no problem just turning off the power to the whole unit but bypassing the thermostat would be a prettier way to go.

Breaking the thermostat circuit is definitely the better way.

 

[Tim Good]

Breaking the thermostat circuit is definitely the better way.

Hmmm... yeah good point.... This was I could also keep the fan inside the fridge running when the timer turns off.

 

[Graham376]

When our evaporator gets well iced up, I just turn the supply off, chuck a cup or two of hot water over it and the ice breaks away. Defrost, clean up and back on again takes about 15 mins.

 

[Bilgediver]

My last fridge in the house was operated like this for over twenty years.