I wouldn't worry about oxygen deprivation from a chunk of dry ice. First, it's sealed in your cooler. Second, even if your cooler isn't perfectly air tight, neither is your vehicle. Your vehicle's heater/AC vents are open to outside air. If you're still nervous, open a window just a crack. If you have a roof vent, open it.<br><br>But I think vandwelling requires the same changes in eating patterns as it does in all the other aspects of life. I think that means not having much food that needs refrigeration, and not trying to keep it cool for more than a day or two. People in much of the world get that day's food that day, or maybe two day's food. Hey, let the market be your refrigerator. If you're boondocking far from stores, then stock up on food that doesn't need refrigeration, like canned and vacu-packed, or dry foods. We're not 21st century house or apartment dwellers anymore. We can't think like that. Think like a 19th century person. How did they do it? Think like a backpacker. How do they do it? Think like most of the people in the world who don't have reliable electricity, much less big-ass refrigerators and freezers. How do they do it?<br><br>I know, it's a philosophy thing. Minimalism vs. having as many conveniences as practical. I once thought a DC compressor fridge would be great. But then I thought about what it would take to run it. Suddenly things got more complicated and expensive. Solar panels, deep cycle batteries, controller, inverter, worrying about the charge state and service life of the batteries, maybe a generator, and fuel for it, and its service life... just to have really cold drinks and some perishable food that isn't as fresh as it would be if I'd bought it that day? Hmmmm...