Your power grid can easily power a 12 volt cooler that can lower the inside temperature 40 degrees F below the outside temperature of the cooler. So if the outside temperature is 85 degrees F then the inside cooler temperature is 45 degrees F, same as your kitchen refrigerator. If the outside temperature is 100 degrees F then the cooler is 60 degrees F and any food will spoil in a few hours.
These kinds of coolers are powered by thermoelectric plates that get cold on one side and hot on another when electricity is applied. Your kitchen refrigerator is NOT based on this kind of cooling – it uses freon and mechanical compressors that liquify freon and then let it “boil” in the freezer section of your fridge – liquid freon boils at -15 degrees F which freezes water to ice and cools the refrigerator.
You have to guess how hot your basement might get without the A/C running and subtract 40 degrees and if the temperature is 45 degrees or less (max 85 degrees F) then this is a viable way to keep food cool. If your base-camp is not in a basement and the room temperature can get more than 85 degrees F then you need a refrigerator, and NOT a cooler.
There are dozens of 12 volt coolers (can be run from your car or electrical grid at base-camp), I picked one that is large enough and has wheels so you can easily move it around: