I took my version 3 prototype ThermoElectric cooler and removed two of the four TEC modules, bypassing them in the cooling loop, to reduce the power draw.

Running two TEC’s at 12v each (in parallel, a sort of “turbo” mode) the whole system draws 136 watts. When I put the TEC’s in series (6v each, or “eco” mode) the whole systems draws 46 watts. This breaks down at 5 watts for the power supply, 11 watts for the fans & pump, and 30 watts for the two TEC’s.

Later on, I also moved the fans to 6v each and reduced the total power draw to 41 watts (the fans went down 5 watts when I reduced their voltage by half).

I’m using a cheap low-efficiency 12v power supply that draws 5 watts all on it’s own just idle, so we could get a 4 watt savings by running if off of a nicer power supply, or a 5 watt savings by running it from a 12v battery directly.

The cooling power is significantly reduced from the 4 TEC version, but I think that having a “turbo/eco” switch that would allow the unit to go from 12v operation on the TEC’s and fans to 6v operation (jumping from 136 watts down to 41 watts) would give the user flexibility to either cool things down when excess power is available, or just maintain temperature when operating off of battery power.   However, even in “eco” mode it takes almost a kWh per day of operation.   But at least it outperforms the Chefman TEC.