We have a bach in an area with no electricity.
It is mainly used in the warmer months (hardly ever is anyone there outside of the Daylight Savings months). It is a wider-family bach, and is used by many different parts of the family. Most people would stay for a maximum of two weeks.
We have always run hot water, cooking and refrigeration using LPG. It works really well for cooking and hot water obviously, refrigeration works OK, but the fridges are small and expensive to buy.
The current fridge we have is showing its age (it would easily be 20 years old, maybe 30), and getting it back to somewhere it could be serviced would be difficult and expensive, and it may not make it any better, and certainly not any bigger.
My idea now is to replace the fridge with a standard 240V unit, and use the savings between that and a new LPG unit (can pick up a 350L 240V fridge for ~$1000, a new 300L LPG unit is north of $2500) to go with batteries, an inverter and solar.
From what I can work out from manufacturers websites, fridges use, on average, about 40W (this Panasonic uses 328kWh/y - divided by 365, divided by 24 gives 37.45W).
I am looking at getting a couple of High Capacity 12V batteries (say 100Ah each), an inverter (500W would be plenty, but maybe 1000W for safety) and a couple of 55W solar panels.
What I am struggling to work out is how long these batteries will last without a charge going into them (say cloudy days) and even if we get nice sunny days, is 2 x 55W panels enough to have a net gain in stored energy over a day. As mentioned, the fridge will need to be powered for up to two weeks at a time (potentially a little more if one group follows another into the bach on the same day - but we need to know the 'limits'). If it works out we will have a heap of power, we would look at running the lighting off them as well (currently we use a normal car battery and it runs the LED lights and charged USB devices for about a week before the battery needs charging - there would be about 7-8 LED bulbs, between 1 and 5W, used only when dark.
While no-one is using the bach, it would be possible to take the batteries home and plug them into a decent maintenance charger. It would be better to leave them there and have the solar (and a controller) keep them topped up. There may be security concerns around this (being it is remote, and the batteries are worth a good chunk of cash).
Has anyone done this/similar, or can provide advice on what I am missing/will need?