All this talk about these new fancy (expensive) coolers!
I just got over a week out my my old-fashioned Coleman metal sided cooler:
https://www.coleman.com/54-quart-coleman-stainless-steel-cooler/6155B707.html?cgid=coleman-coolersandwaterjugs-hardcoolers
The cooler sat in the back of my truck for the drive up to the mountains, through 105 degrees on Saturday. Then it sat outside at camp under the trees for a week, with temperatures in the 80's all week. It was a "wilderness" camp- no ice resupplies. The cooler was opened several times a day to obtain cold sodas and replace with warm cans to be chilled. Next Saturday it went back in the bed of my truck again through 100 degrees. On Sunday at home, when I finally unloaded it, it still had ice cold drinks!! The ice was "slush" with plenty to still keep it cold!
If you see my pics on the Corral Hollow Trail thread, you'll see this cooler in the back of my truck- and the boys drinking ice cold sodas at the overlook. This was on Saturday, the 7th day of our trip.
"How is this possible?" you say.
I used a combination of "Dry Ice" and regular ice. One block of dry ice on the bottom, covered with cube ice. Then the drinks/food etc.. go on top. If you want frozen food, put the food/ice in first, then the dry ice on top. You could keep ice cream frozen this way.
Caution: Play with the ratios of dry ice to regular ice to fit your climate and cooling demands. The first time I tried this, I got frozen eggs.
Oh, and I never drained off the melted ice water. Ice water is still "icy," and if you drain it off unnecessarily- you lose all the coldness! Only drain water when adding ice, and/or the water threatens to spoil non-waterproof food.