[chuckm]

forgottenmindset,
I can assure you that it will be more often than just "every few days." I know a little about the gatoraid coolers... Back in my high school days, I played football. Just before school started, we had summer "two-a-day" practices. First practice was ~8:30am, second around 3:30pm. The junior varsity guys had to make the ice water and they were, um, encouraged to get to the ice machine early before the afternoon practice. Why? The ice from the morning practice would be practically gone by the 3:30 practice, even when stored in the shade. (And the last group to make up their jug didn't get much ice.) Sure, we are talking about Louisiana heat. But you're looking at storing your ice inside a vehicle, where the temps can go over 130F pretty quickly.