I ahve small holding with generator no connection to grid, I have 12v system to cover fridge, lights and tv etc, and only use manins on generator as not sufficient power to rely on by the two solar panels and wind turbine... in windy summer I produce loads and dump it to 12v hot water heater in normal tank which warms water, however near xmas in uk when no sun and little wind then over few days batteries can start to fail and then there is never enough of either to boost them back up to full so over 3 months they run on empty and sometimes when generator on we need battery charger to boost so in the ideal place sun and wind great but in real life either loads or nothing... but if you have no grid 12v is comfortable for 24/7 with generator when needed.