One of us with these 12v 'coolers' should also mention that the manufacturer may offer an insulating jacket. My Dometic CF-18 unit offered an optional jacket for $50 that I was very impressed with, and this is especially helpful if hoping to use the cooler as a freezer when the variance between ambient & cooler temps will be 50-70F, a HUGE spread. My guess is that folks who are pleased with these units when used as freezers are more than likely located in temperate climates and running the units at dock
power/charger 'on' voltages of 13+V. I doubt an energy conscious, <100 AH/day cruising boat will find them viable as a freezer when used in climates typical for cruising.
Lots of apples & oranges comments here related to energy consumption
of these units. Using my CF-18 unit as an example, here are apples lined up with one another:
-- Dometic sez: 2.9 amps is 'average power consumption', a gross generalization at best. As a fridge or freezer? Tropical or New England
wx conditions? 2.9 amps X 24 hours each day?
-- My CF-18 as a fridge: 4.7 amps @ 13.2V DC ~ 15 mins each hour in FL fall weather
and with the insulating jacket in place; consumption
is therefore ~30 AH day. Not a terribly high number but equivalent to what my Isotherm
12V holding plate system uses for fridge & small freezer function & 4 times the capacity
-- My CF-18 as a freezer (with remote
temp sensor showing avg temp of 15-18F): ~30 mins each hour under same (for a cruising boat, almost ideal) conditions as above; consumption is therefore ~60 AH/day. Interestingly, that's not much less than what our average daily consumption is when cruising (~70 AH/day).
BTW I find, at the above freezer temps in the 'teens F, that water
in ice cube trays doesn't freeze hard - it only gets slushy. The temp sensor I'm using is accurate within a few degrees. Any thoughts about this?