Looking to buy ice cooler to keep drinks cold 6 days

My truck has an electric APU, and you're right that if it's using the AC, secondary circuits will shut down before the 10hr break is up. So, what I do is leave the windows open whenever it's not expected to rain, I bought a 12V fan for air circulation, and all other electronics are shut down for the night. GPS, CB, etc. Phone and tablet are charged during the day while I drive, so they aren't drawing all night, either.
Make sure your shop tests the APU batteries regularly, too. They can, and do, go bad prematurely.
When I buy my own truck, it'll have a real APU, for sure.

 

Honestly, I turned my mini fridge completely off. When I want a cold drink, or string cheese, or a drinkable yogurt, or a SlimFast shake, etc, it's far easier for me to reach into the Igloo next to me instead of awkwardly fumbling blindly behind me with one arm. If I know I'll be running harder than usual for a few days, I'll run my mini fridge on low, with excess containers of fruit and such in there... Thus, if it shuts off somehow, it's not as big a deal. I'm not losing dairy products, but my chunk watermelon might not be as cold...

 

My Igloo is a 12V thermoelectric cooler. I primarily use it instead of my mini fridge.

 

There are some YouTube videos reviewing all the rotomolded coolers (like Yeti). They found the Coleman Xtreme held ice just as good, and its way cheaper.

 

https://www.walmart.com/ip/Pelican-...Deluxe-Cooler-with-2-Insulation-65qt/21804289
it's actually a 64 qt. best bang for the buck,($305), according to 4 wheel drive mag.

 

Ouch, and also $309......