I'm planning to cut my grid connection and go full off-grid. Which raises the question of how much capacity I really need. And what you see here is me trying to answer that question based on ~51,000 5-minute data points of usage data my power company provided to me, complete with custom-made python script to parse all that data and pretty charts! (Yes, I have 6 monitors. And this kind of shows why.)
And what I'm really torn about now is how much battery capacity I need. Should I get enough to cover the absolute worst case scenario (~66kwh) or is something closer to my average overnight usage (~20kwh) acceptable?
Not the absolute end of the world if the batteries run dry and I need to temporarily supplement with generator backup, I suppose. Nobody is life-or-death depending on any electrical appliances here, and even on the coldest days, waiting a few minutes to go start a generator isn't a huge deal.
But definitely would like a word from the wise about how much battery capacity I really need. And also how much solar panel wattage I need, I suppose.
I had an electric water tank for some years, it did only heat during 4h a day splitted in 2 morning and 2 afternoon, thats more than enough. Just install a temperature logger so you keep track of the temperature. In terms of batteries, they are too expensive for a normal use, invest on a few more panels and try to reshape your consumption.