Author Topic: Put new freezer to fridge controller online yesterday... .41kwh in 24 hours  (Read 2324 times)

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Mary B

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I recently bought a new freezer so I could move my 2 year old one to regular freezer duty to replace one that was 15 years old. 15 year old one still works, just not as efficient for running off solar. I was using a mechanical temp controller to control the freezer/fridge temp(freeger? needs a name!). The temp swings on it were wide and I had to manually switch to grid if the batteries were low. Short power outages could lock the compressor too causing issues.

So I picked up a 30 amp transfer switch used for marine shore power switching. I run inverter power as mains and when it shuts down it drops to secondary power which is the grid.  I added a cheap PID controller that was recommended by the homebrew crowd, a solid state relay to save wear and tear on relay contacts and a heatsink for the SSR.

Picture was on my test table with just a light for a load. Works well, I have a 3 minute compressor delay to prevent hard starts, holds temps within 4 degrees where I currently have it set. I tossed the Kill A Watt meter on it and in the last 24 hours it used .41kwh and that was after putting fairly warm leftovers in it from yesterdays ham. Nice having everything automatic with little to no effort on my part for controlling things. I check bat voltage a few times a day is it.