no one likes them, everyone hates the power it takes to run them, and they won't freeze ice cream ... generally.
4 to 7 amps per hour to run, but simplicity redefined if you have the juice to do it. Generally cools an insulated area to 30 or so degrees below ambient ... maybe more with good insulation
and more yet if one uses the higher powered units(5-6 Amps per hour)
I had a Coleman unit to which I added a second fan inside and increased the inside insulation
with about 1" foam and everything stayed really, really cold .... once it got cold. I used this for about 4 years and was very satisfied ... once, in July(not a real hot day, mind you), I froze a 1/2 gallon(maybe a quart), of milk to completely rock-hard frozen, like a brick. A fluke? I'm sure, but nonetheless ... solid frozen.
I usually ran the units for a few hours in the early(cool), mornings, reduced my access during the hot day(to reduce loss of cool), ran it an hour or two in the evening, and ran it again around midnight for a few hours ... tried to keep run time to about 1/2 time overall to make my total usage for 24 hours at 50%. About 4-5 Amps per hour for 8 or so hours for a total of about 30-40 amps.
Running the peltier unit during the hot part of the day is self-defeating, and the cooling
of the peltier on a 90-100 degree day would actually mean you could be "heating", the contents ... that's why I never ran it during the day. Often, I would spray the hot heat-sink with water
to help it keep cool ... always had a spray-bottle for this purpose.
Now ... I like milk, and I like milk near icy cold ... so cold that it's too cold to guzzle ... this peltier would make that milk, that cold ... consistantly.
If one wanted a "cooler", similar to an ice chest, that keeps things "cool", not "cold", I venture to say, the run time on a peltier unit could be further reduced. If you built a unit that took ice(where the melt wouldn't be a problem), to give the peltier a kick, you might further reduce your actual run time to a point where a decent-sized solar
panel will give you enough juice to run the unit.
In any case, given the inefficiency of a peltier, and the lack of truly cold contents, the cost is ridiculously minimal, enough parts
can be carried in a small bag for a few complete rebuilds(at a truly minimal cost).
It's not a Frigoboat(which I have on my newer boat), but with lots of insulation and a minimally invasive(?) way of getting things out(during the hot day), I think it would be worth a consideration ... for the right needs and the right frame of mind.
Any negative posts about peltier, are probably completely true, but I think Peltiers have a place for the right situation ...
... absolute simplicity
... absolutely cheap
... better than nothing(if a real unit is too much $$)