I have never noticed the cab heating up with mine.
As far as insulation, I Was just out camping this weekend with the fridge and had it on a different battery in the bed of my truck. I had it running on FF which is fast freeze or flash freeze. Basically the highest draw on the battery. It lasted about 20 hours before the low power kicked in and automatically shut it off. The temp was hovering around 100 and it only got up to about 55 degrees sitting in the blazing sun with no insulated bag. Took about 5 hours to rise from 35 to 55 but got no higher. I have the 63 quart edgestar and am looking to maybe get a smaller one so it will fit in the cab of my truck easier.
As far as insulation, I Was just out camping this weekend with the fridge and had it on a different battery in the bed of my truck. I had it running on FF which is fast freeze or flash freeze. Basically the highest draw on the battery. It lasted about 20 hours before the low power kicked in and automatically shut it off. The temp was hovering around 100 and it only got up to about 55 degrees sitting in the blazing sun with no insulated bag. Took about 5 hours to rise from 35 to 55 but got no higher. I have the 63 quart edgestar and am looking to maybe get a smaller one so it will fit in the cab of my truck easier.