Don't know how many do this but I have not seen it done very often.
If you just need to keep food cool for awhile eg. next camping stop or a trip away from the van.
Instead of forking out for a largish portable fridge --- just buy a small one and set it on freeze --- keep them blue freezer blocks in it and just keep replacing the ones in your Esky/Cooler
cheers
Coyotte
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BOWRAL --- Southern Highlands -- N.S.W
Love this road -- Love this life-- It's in my blood --It's in my soul