Oddly I'm also looking for the answer to this question as well. Thanks so much. We are looking to come off grid with our solar panels and it seems a closed market is going on with solar companies and the electric suppliers. All the national solar panel suppliers only supply a 3.6kw inverter, and won't fit anything else, as such its impossible to go off grid with such a small inverter. You can however do it yourself, or if lucky find a good independent to fit a system with a bigger inverter, and a battery storage you can add to as required, but its not easy. You may wonder why I would go off grid, simple the standing charges for electric in the UK are rising far faster that electric prices, and looking at this trend in around 5 years over 50% of your electric bill will be standing charges, put simply you will be paying a significant amount every month before you use a single KW. 99.9% of people who have had solar panels fitted are completely unaware that there system means they are tied to the national grid, without a complete new system to incorporate an off grid inverter, and extra battery storage, plus in most cases additional solar panels they will be paying these standing charges, they have no choice. Simply they are been sold a product that will keep them tied into the grid, which keeps them paying the standing charge. Its logical, how else will electric companies make money for their share holders if they don't keep people tied into the grid? Thanks so much for the answer it really helps.
I tested by turning off the main incomer, and my solar panels still work, however I am limited to a pair of double sockets and a FCU the latter feeds the central heating, as you say the inverter is around 3.5 kW so maximum power one can use is that.
However the freezers use too much, background usage is around 350 watt, so the battery is not enough to do the night, but unless we have spare power to charge the batteries, then there is no point in having more, so to be self sufficient one's solar array would need to be far larger than mine, I have seen nearly a 5 kW charge on a good day, but to be self sufficient I would need three times what I have now, and my roof is simply not big enough.
If I need just 1 kWh from the grid, then idea of going island is a non starter. I think without the grid we could with some candles or touches we could survive, but not live the life we want, yes we could fit showers from the hot water storage, get a new washing machine which uses a hot fill, but we still need the oil for the central heating. Maybe we could cut and burn wood, we could also build a mud hut, and one has to consider if one really wants to be a slave to the sun, arranging the whole of our daily routine around how much sun light we have got.
I am guilty since getting solar panels, every day I have a look on how they have preformed, and am aware if I make two cups of coffee at the same time it costs more than making one after the other. I suppose this is what the government wants with the smart meter role out, rather pointless when in my case the existing meters already allow me to monitor usage 20 second by 20 seconds.
There has to be a trade off with showers, the more water the quicker we can shower up to a limit, so to say a 7.5 kW is cheaper to run to a 11 kW is not quite that simple. Woman it seems get the dirt more ingrained than men, and need a longer shower, the miners did not really spend that long in the pit head showers.
It is questionable is a bath better? As it does not depend on how long you are in it as to what it costs, but since moving into this house I thing I have used the bath twice. One bath has my wife's e-bike parked in it. But in theory we could fill the bath from a kettle on the fire. I have not got a back boiler, but it would be easy enough to install the pipes are very close to the open fire.
We use to have central heating years ago
one fire in the centre of the house, we used no electric, and only oil was Whale oil, using fossil fuels has been the really good for the Whales, it has resulted in the end of Whaling, we really don't want to return to the old days.
