24v House

[Bulworthyproject]

Until a couple of days ago we planned to make the electrics of our off grid house 12v (dc).

There are some downsides compared with 240v (ac):
Most people use 240v (ac) so there are more appliances available for 240v (ac)
The amperage is higher so the cables have to be thicker (therefore more expensive)
Running high wattage appliances on 12v is not as practical (due to high amps)

However:
A lot of mobile appliances are available in 12v to plug into cars and these tend to be more energy efficient.
You do not lose efficiency converting dc (from solar) into ac (through an inverter) just to convert it back into dc as this is what most small appliances work on.
Our whole ethos prevents us from regularly using high wattage appliances.

Balancing this all up we decided to go for 12v (dc) until we looked into 24v (dc). The amperages are halved so the cable costs are lower, as are regulator costs. Other than that it is the same as 12v except for the availability of appliances. Lorry drivers use 24v appliances so there is a market out there but it is not as large as that for 12v stuff.

Does anyone have any experience of 24v systems, the availability of appliances and any other issues?

[Thurston Garden]

I don't have any experience really but will be interested to watch this thread. I seriously considered no grid tie when I built the straw hoose and keeping it 12v but I was talked around following a few threads and discussions on the Navitron forum. The thought on there was that £3k for my grid tie was not expensive (contrary to my thinking!) and to tie. I did, and I am not sure if I made the correct choice.

My consumption is small 0.6kWh a day although this did rise when I bought a wee freezer. I think if I had the chance again, I would probably not have had the tie.

[Bulworthyproject]

We're a bit far from the mains for grid-tie ti be practical and there is definitely something about a self contained system that makes you think about energy use. In a lot of situations grid-tie is the sensible option though.

0.6kwh per day is pretty good.

[diggernotdreamer]

How do you use so little electricity, try as we might, we cannot get our electricity useage down lower than about average 18kw a day

[Thurston Garden]

18kw a day

There's only me in the house. No dishwasher, no TV, only an A rated wee fridge, a mac mini and an amplifier on in the evening. One of the key things for me is I will make bread or do my washing when the sun is out so I am using my own electricity. My average consumption has definitely gone up now I have a freezer. Even at that, it's not near 1.8 neverheed 18. Are you sure next door don't have a secret cable connected to your supply

[Bulworthyproject]

Having lived 4 years in two caravans stuck together with 120w of solar panel, we dream of having 0.6kwh a day of electric. Previously when we lived in houses goodness only knows how much we used.

Not having a tv definitely helps. (not just with power consumption)

[Thurston Garden]

Having lived 4 years in two caravans stuck together with 120w of solar panel, we dream of having 0.6kwh a day of electric. Previously when we lived in houses goodness only knows how much we used.

Not having a tv definitely helps. (not just with power consumption)

Being Scottish and miserable helps me!

[diggernotdreamer]

Are you sure next door don't have a secret cable connected to your supply

Hah, we did wonder that. We spent several weeks logging our useage. Then we turned everything off until the wheel stopped, so unfortunately, it is us that is using it. We have a fridge freezer, and we do watch telly in the evening, it all seems to add up, oh and the wizard is an engineer so we often have lights on in the workshop and he might run some machines if he gets a bit of work, we have the immersion on all the time, we found it was actually cheaper to leave it on then put it on when we wanted showers, and at the end of the day, we would have to boil kettles of water to wash up, so I guess we just have to grin and bear it, we don't waste it either

[woodi]

Hi - we lived for a long time in a truck, using 12v electrics powered by solar and wind. We've now moved about 10 feet away into a cottage that we were going to wire for 24volt, but eventually decided on 240v.
Here's why.
12 or 24 volt means you're carrying fairly high currents and so need heavier cable. It is also harder to find good durable sockets etc for 12 or 24v gear. Also you will need to rewire if you ever change your minds.
We plumped for wiring for 240v, using LED bulbs throughout. Our power comes in from only 500W of solar, through a couple of victron charge controllers, and into a pure sine inverter. Losses really are minimal, and we just use appliances sensibly. It runs all the lights in a 1 bedroom cottage, our fridge, a laptop and router. We've 500Ah of AGM batteries, and we don't make any significant dent in their state of charge.
Low voltage is grand if you have short cable runs and 12v appliances, but don't discount inverters and 240v.
cheers
Steve