I use a couple of Campingaz Extreme
cool boxes on the boat & a 3 way fridge for camping. The Campigaz boxes are the dogs danglies, they are bomb proof & keep stuff cool/frozen for a couple of days even in hot weather. I use 1.5l bottles of frozen water as ice packs, that way you can drink the water as it thaws. We used to have a Coleman 12v cool box prior to the 3 way & it ate batteries, & didn't get that cool. The 3 way (240v, gas, 12v) that we have now is spot on, it was a cheapy from GoOutdoors & we've had it for about 5 years.