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Hi Alex
We've been living off grid for about 8 years now and after a steep learnimg curve the best decision was to go 48 volt.
When we started building we were given all the wrong advice and went down the 12 volt way.
This meant 4mm wiring on short runs, over priced 12 volt panels, expensive 12 volt breakers.
We started with expensive 12 volt lighting (no leds available) and 12 volt tv as well as a couple of cheap inverters.
When led down lights first came around I used to make my own bayonet hybrid out of old globes. Now they cost $5 of the shelf.
One day I got a cheap offer of 200 watt / 24 volt panels from a solar company that went bust.
I bought a heap of these bust no use on a 12 volt system so they sat around for afew years.
Prices came down, mppt got cheaper, so we did the 48 volt change over.
Now its same batteries but 48 volt, panels are in banks of series at 120 volt dc to a 60 amp controler.
A decent inverter and a 7.8 kva honda genie and no more gas fridge.
When I originally wired the house I did dual 12 volt and 240 volt with homemade powerpoints that took cigarette lighter plugs.
When we did the change over I kept the 12 volt lighting and the odd powerpoint and built a robust 48v to 12v dc step down transformer and kept this system.
The batteries are getting a bit tired so soon we have to replace them. Lead acid is still cheaper but a bit of maintenance is required.
A new school of thought about headroom for cloudy days is being talked about.
Normally you design for 2.5 cloudy days and try to keep discharge to under 30 %. This means more than double the cost of batteries is needed. This way you get about 10 or so years out of the batteries but the last few years the batteries are a bit tirerd anyway.
Get a robust genie with good charging and auto start the system, use the 50% or more discharge rate and only have 1 cloudy day backup.
Yes you will hammer the batteries to only about 5 years lifespan but you need about 1/2 the bank.
Petrol is cheaper than batteries in the long run and technology is changing so each time you upgrade the battery bank it should be cheaper and more efficient
Its still better than paying 70k for the grid so we can pay a bill!!!
In the future base load grid will be battery and stored hot salt for turbines and a shift from total reliance on gas and coal for power generation.
But thats not for a while we all just have to use less and build smart efficient housing.
When you live off grid you always have one eye watching amps and the weather and live accordingly, no lights are ever left on.
I think if houses were installed with coin and note machines on power meters so you pay as you use I think people would get used to turning off plasmas and lights in empty rooms and turn off residual load from standby appliances.
Anyway good to see that im not alone in our way of living
Cheers
Andy
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