Since fridge0 uses a standard chest freezer running on AC power, an inverter is needed to convert the solar DC power.

When selecting an inverter, make sure it produces enough watts to run your fridge, and that it can surge to provide enough watts to spin up its compressor motor. The latter could take several times as much watts for a second. Fridge specifications probably won't say what the spin up power is, so assume 10x or so.

A pure sine wave inverter is generally considered to be a good idea for fridges, as it may produce less strain on the motor and be more efficient.

Bear in mind that inverters may consume some power even when nothing is connected to them, to run their internal circuitry. This can add up over the hours that the fridge is not running.

One option is to use a relay to cut DC power to the inverter when fridge0 is not running, but some inverters may need a button pressed to power back on, preventing doing that.

Joey Hess's fridge0

I use an AIMS 1500 watt pure sine wave inverter. Model #PWRI150024S.

It uses 4 watts of power when not under load. So over 24 hours, it would waste almost as much power as it takes to run my fridge for 1 hour. While a single deep cycle battery would more than suffice to keep it and my computer control running for days, that cuts into the winter power budget more than I like.

So I reverse engineered the inverter's RJ22 control port and designed a control board that can put it to sleep under computer control and wake it back up as needed. See


Please add your inverter information here if you do a fridge0 build.