I resectfully disagree with you John as in order to wire even a moderately sized house with extra large cable to run a 12v system would be prohibitely expensive. Also if on the 12volt system as battery power is used up then the voltage supplied wil reduce accordingly, ie 10% of power used , now at 10.8 volts. 15% = 10.2 volts. Very dim lights and probably not enough voltage to run all that you want and very much reduced life in your batteries.
However on a 24 or 48 volt system with proper inverter/ charger, then there is no voltage drop, its 230v all the way.
Also if you need to buy anything else in the way of appliances they are readily available and not at an exhorbitant price.
Try charging a phone , rechargeable batteries, or running security lights or using a bread maker, a food mixer. Do you really want to be starting a generator, (which costs money and pollutes EVERY time you use it) because you want to go on line to look at this forum for example?
Generators cost a lot of money to run. Plus you have to go and get the fuel in the first place, which also costs money.
If you are living here in the campo then solar and wind is the ONLY way to go.
Re Navitron,
I bought one of the first Navitron solar water heating set-ups 7 years ago.
IT IS FANTASTIC.
My 20 tubes produce enough hot water for 4 people all through the summer and enough for one person in the winter. I have invested in a top up gas boiler for the winter months Nov- March which uses very little gas as it only tops up the partially heated water to 80c
Just my opinion on the subject, as I want to live as 'greenly' as possible :)