For a while our freezer had been at best a beer fridge. That is good enough to produce ice cold water and wine, not good enough to produce ice for Gin and Tonic! I will try to explain why.

Sounds very much like a first-world problem if you ask me :-)

Now my concern was that even if we replaced the batteries (at vast expense) was it the fridge and freezer that needed replacing as they were taking soooo much power, or, even worse, our 7 solar panels, were they producing the power they should be. What if we replaced the batteries and then realised that it was the other equipment that was the problem and we still would have no ice!

It's not that hard to trouble-shoot. I bought some devices from China that can be connected to the power supply i.e. to the fridge to count the watt-seconds or kilowatt-hours it consumes - I suppose it should be possible to find some similar counters locally. If not, you should have a multimeter on board (and if you don't - buy one or two!), allowing you to see how many amperes the fridge is consuming (and multiply with the battery voltage to find the watts). It's a bit difficult with the fridge since it's running duty-cycles, and the energy consumption is dependent on how much it's on versus how much it's off. To get an approximation, you can set up a timer and measure the electricity consumption i.e. every whole hour, and take the average of the numbers.

Checking the solar panels is also quite so easy - just use the multimeter to see how many amperes it's delivering. Often the charge controller also has a display (sometimes the display has to be purchased separately) showing the stats.

Check that the power drawn from the battery bank matches up with the power drawn from the fridge when you believe there is nothing else drawing electricity. Perhaps there is something else eating your energy.

Also, you should find out if your battery bank is fully charged or not when the sun goes down (and run the generator for a while in the evening if it isn't).

Fridges and freezers do consume quite some energy, but this sounds excessive. There are special boat models that are supposed to spend much less energy than the regular units meant for installation in houses.

There are three reasons for a fridge to spend "too much" power;

• Inefficiencies in the heat pump. Make sure you have well enough ventilation of the heating coils on the backside of the fridge. Make sure they aren't covered with layers of dust. Some people has reported that they have had great success saving power by installing a fan to ensure a good air flow on the back side of the fridge. Old heat pumps often eats more power than newer pumps.
• Heat lost into the fridge. Make sure the door is very well closed, and that there aren't any damages to the fridge. It should eventually be possible to measure how well the insulation works, i.e. by leaving the fridge with only some well-measured amount of cold water at some well-measured temperature over the night and see what the temperature is in the morning.
• Putting warm things into the fridge. Try to only buy beer from the fridge when you're in the shop. Buy frozen food and defreeze it in the fridge. It's also possible to buy freeze boards (something like those from amazon) - if buying standard sizes it's possible to exchange thawed elements with frozen elements i.e. at camping places.

Another trick is to run the fridge on full power (i.e. put the thermostat low) whenever the solar panels or generator is delivering plenty of energy, and lower power (put the thermostat high) when it's needed to save the batteries. Use those freezing boards to keep a stable temperature.