Lifeline has a 24 volt fridge/freezer that we run on solar power. The unit is custom made: 2 boxes (fridge 120 litres; freezer 25 usable litres) with 5" of insulation glassed and two packed; top opening with two separate lids for fridge and freezer. To optimise power usage, we run the freezer between -1 and -3 degrees. A series of channels in the wall between the freezer and the fridge allows cold air to leak over to the fridge, thus keeping stuff cold. Simple and efficient and probably "cool" rather than "cold" in the upper part of the cabinet. I have a lift out basket at the top of the fridge which allows me room to reach down the side.
Before we leave our "home base" I stock up on 6 months of dry goods (mainly so I don't have to lug them to the boat without a car). Then I only have to shop for fresh stuff when we are away.
When I shop for fresh produce I buy 3 - 4 weeks supply so we do not have to go into port if we don't want to. (In general we like to stay away from port, particularly marinas, except to use the conveniences.) Conveniently, that is also the maximum amount I can cram into our fridge. I know what to buy because I do a stocktake against my master provisioning list before I shop. This has 3 columns: one lists how much of each item we use in 28 days; in the next I write how much is on hand; in the third column I write how much to buy. This becomes my shopping list.
Back at the boat, all apples, oranges, hard pears, hard nectarines, hard peaches, mandarins and passionfruit go into two big fruit bowls in the saloon; half the tomatoes are stored out of the fridge in a basket on the bench, the other half in the fridge; ditto lemons and limes; ditto bananas which are kept separate from the apples to avoid premature ripening. Chillis are strung on fishing line around my kitchen window. A whole pumpkin and a whole cabbage are stored down below in the tank room. Ditto potatoes, sweet potatoes and onions, which are in a washing basket lined and covered in newspaper.
So far so good. Nothing much out of the ordinary there. The rest of the stuff, which goes in the fridge, has to be dry and wrapped. So first take everything out of the plastic bags from the supermarket. You will be surprised how wet it is - they spray the produce to make it look fresh! Pay particular attention to drying lettuces and broccoli
You will need at least one roll of paper hand towel for drying and wrapping and medium sized freezer bags and perhaps some of "Rob's long life bags".
When dry, wrap each item in several layers of paper towel before bagging together vegs of the same type. Snow peas, beans etc can be laid out on paper towel and then rolled up like a jewellery roll. Similarly carrots. Broccoli and beans are the shortest lived of the vegs so if you want to keep them more than a few days, use a "Rob's" bag (after wrapping).
I store the firmer, longer life (see below) and "spare" vegs in the bottom of the fridge, gradually layering up to the bottom of the basket with the softer vegs and ones to be used up more quickly. Those currently "in use" (eg lettuce I'm taking leaves off, cut avocado, cut onion etc) are kept in a plastic bag (wrapped in paper towel first) in the basket with the other opened packets, jars, marg. etc that need refrigeration.
The wrappings need to be inspected regularly to make sure they don't get wet. For me this is not too much of a chore because we eat salad sandwiches most days, forcing me to open up and re-wrap most of my bags.
Here is the longevity of fresh produce in the order of what to use first:
Beans 1 - 2 days
Broccoli 2 - 4 days (longer with a Rob's bag)
Cucumber 14 - 21 days
Celery 14 - 21 days
Shallots 14 - 21 days
Zucchini 14 - 21 days
Eggplant 14 - 21 days
Carrots 21 - 28 days
Snow Peas 21 - 28 days
Avocadoes 21 -28 days (Buy hard ones and as needed bring them out of the fridge to ripen)
Tomatoes 21 - 28 days (Use bench ones as they ripen. Then bring out fridge ones to bench)
Potatoes 28 days or more
Pumpkin 28 days (after cutting, remove seeds and sprinkle pepper on cut face before wrapping and bagging and putting in fridge)
Onions 28 days or more
Sweet Potato 28 days or more
Cabbage 28 days (Peel off leaves from outside)
Using "Rob's" bags definitely extends the life of most vegetables.
We try to shop in the morning so the fresh stuff gets wrapped and put in the fridge with plenty of sunlight left in the day to charge the solar panels.