We have a gas fridge as well, but a gas bottle only lasts 4 weeks in the summer, longer in the winter. You must have a very efficient gas fridge nobrot for a bottle to last that long. We rely on solar and have a good system and we run a fridge from this as well. We only really use the gas fridge now in the summer to put the drinks in.
We had our solar system put in by llatjes and they have done a fantastic job. So any one out there that wants a good solar system don't scrimp and use somebody that says they know what they are doing (because they probrly don't!!!) Use a good company like llatjes