We've had This Guy since before we got the Lance (2013). It's proved really good at keeping things cool, with an up to 40 degrees difference between outside temps and cooler temps.
It draws about 5 amps at 12 VDC, so a 100 watt solar panel can keep up with it, and even as an unpowered cooler, it's well insulated.
We got the Koolatron 110 volt adapter, which has just this last trip failed, and we're testing a generic 10 amp replacement, which seems to be working well.
We also got the Koolatron Battery Saver Model F70110, which is designed to cut off drawing power if the battery voltage drops too low. Sadly, we didn't bring this with us on our trip, and thusly killed our battery when we had a power outage.
So, this is the 'booze box',which has kept our beer and wine chilled these last 4 months.
It's great 
