An associate of mine runs 5 houses on converted power from Direct current to Alternating current, he uses surplus glass mat phone batteries, the system is 48 volts DC but if you buy brand new quality batteries and cycle them you will only get 5 years max out of them but if you run the batteries on what is called the float which on the 48 volt system is actually run between 54 volts at the top and recharge at 52 volts my associates battery system is over 20 years old and still going strong.

Increased voltage and running batteries on the float is an affordable system, strict 12 volt systems cost a great deal over the long term as much as 10$ a watt on average, the higher voltage systems can have multiple means of charging, my friend uses generator, photo cells and hydro and wind to keep the system on the float charge even with heavy load of five homes.