As others have said.
I have had 2 or more of those power hungry Ice chests. One perfectly good sitting in the yard right now, same place for over a year now
They are ok if used right, by right I mean NOT as intended!
They do not get cold fast at all normally. Put cold meat in one at ambeint temps at the store and meat warms up before the cooler gets cold. Run the cooler on the way to the store so it's cool before you put in the meat and it works ok.
Manual says do not use ice in it, if you want something cold you use the ice anyway!!
IF you leave it plugged into the car for awhile with engine not running, forget starting the car later!
More similar reasons you may have found it somewhere, maybe it was one of mine before I Knew what a peltier was. Hopefully the newer ones work better but I dought it.
That Peltier, cooling heating device, is a nice toy and expensive to buy. Save it even if you don't use it for beer anyway.
Since you have it, play with it. Heat one side HOT and cool the other, makes a little power, or should.
As already said, 12V at 5amps is 60watts. Alot of money for a solar pannel to run it for no more that it does.
If sun comes up good around 7Am I would not expect the beer to be cold untill 12Noon. Even then the best will probably only be cool beer, not actaully cold. When the sun goes down and the pannel stops making power, you have an ice chest without ice full of beer which is slowly getting warmer.
For the money and effert to have cold beer using that unit you might be better off making ice at home in the freezer and filling a $5 ice chest with it.
All is not lost though, you could make a nice 4-6 can cooler to plug into the car while driving and have a cold/cool Coke or Pepsi instead.