3 way fridges

3 way fridges require a heat source as their prime energy. On gas this is a flame and on 12V and 240V it is a resistive heating element. In all three cases the amount of energy required to keep the fridge cold is the same, about 80W for my 3 way. The gas flame can easily produce this much and at 240V only about 0.3 amps is required however on 12V 7A or 8A is necessary and once we start to pull those level of current it is hard not to create a voltage drop across connectors, wires, fuses etc and with only 12V to start with a drop of 1V2 means we have lost 10% of our power whereas on 240V a 1V2 drop equates to a loss of only 0.5% of power.

In short; at 12V ensure you use high quality connectors capable of carrying at least twice the fridge requirement, as thick a wire as sensibly feasible and keep wiring runs as short as possible.

Mike Harding

I agree entirely with Mike. 3 Ways are often denigrated on this site when the real issue is often inadequate wiring & connectors combined with long wire runs. .
While not supplying everyones needs, the 3 way sure does away with the need for
carrying a portable power station when running on gas....oldbaz.

I have an old Finch which works very well in the back of the Prado. The wiring to the socket is obviously "up to it" and the lead on the fridge is short. Previous owner had a long extension to run from cig lighter to boot and always complained that it didn't work properly on 12v. Set them up properly and they are fine!!