Using a hacked dorm fridge thermostat to control an inverter

[PorchDog]

Exploring a way to automatically turn an inverter on and off while powering a dorm fridge. I see where most inverters have a remote on/off function, which appears to be a simple switch closure---closed is on-- open is off.

My idea would take advantage of the already existing bi-metallic thermostat inside the refrigerator to turn the inverter on and off- the fridge would stay connected --with the compressor wired straight to the power cord such that when the inverter turns on (as commanded by the fridge thermostat) the compressor would start immediately and run until the thermostat contacts open and turn the invertor off. This of course would require a small dedicated inverter.

My concern here is whether the inverter can handle starting up -- or be damaged--with the compressor load across the output terminals at all times. (Although I assume this is the case in many applications)

The goal here is to minimize or eliminate idle current usage.

Anyone done this?

 

[Hedges]

I think that should work.

There are inverters which wake up occasionally to see if a load has been turned on. That makes consumption pretty low.
Obviously they're expected to start into a load. Don't think that is any problem.

Some DC power supplies need to have voltage ramped up before load is applied, that's a different "soft start" issue, don't think anything like that applies to AC. (but AC loads can require a surge, even/especially if AC is at full voltage.)

 

[efficientPV]

I do that with my fridge. Just bring a couple wires across the inverter on switch. Current is typically about 25ma. Momentary push button switches require a micro to be successful.

 

[timselectric]

I don't see any problem with this plan.

 

[sunsurfer]

My concern here is whether the inverter can handle starting up -- or be damaged--with the compressor load across the output terminals at all times. (Although I assume this is the case in many applications)

The goal here is to minimize or eliminate idle current usage.

Anyone done this?

I have a Low frequency inverter (2.8kw) that I shut off often when I'm gone from the house. I start it under load all the time. A fridge and a freezer come on under load when it starts up. Its holding up so far. I never searched the manual to see if this is hard on it or not.

Smart way to save some battery power. Before I got my batts, I just ran my fridge and freezers while the sun was shinning(or gen was running) it did fine if there is allot of mass in them.