Everything stated above is correct. Most boat fridges run about 50% of the time. So when using the compressor label to calculate Amp Hours understand that the fridge will normally run only half the time or about 12 hours per day. The beer comment above is, sadly, also true. If you put even 12 warm beers in your fridge, the fridge will probably run for 24 hours non stop before the beer is cold and the fridge goes back to running half the time. Then consider that you should only use half of the batteries Amp Hours before recharging. Therefore, let's assume 50 AH used per 24 hours without the warm beer shock or 100AH with the warm beer shock. Then double the resulting number for battery size calculation (for each 24 hours). Or, you could get a Yeti cooler for your beer.
