So I'll be driving for about 3 days and was going to leave all my batteries and charger in its fire proof container which is an old WW2 cooler. Wondering if they will be fine to sit in the trunk or should I toss em in zip lock baggies and put some ice in a baggie and put it all in the cooler ice on bottom just in case. What would you guys recommend? BTW it's going to be in the high 90s the days we're driving.