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My household of 3 is off-grid, running off a 15kW PV array and 24kWh of LiFePO4 batteries, with 100% electric appliances and hot water. (Location is mid-latitu
by Andys 3y ago
My household of 3 is off-grid, running off a 15kW PV array and 24kWh of LiFePO4 batteries, with 100% electric appliances and hot water. (Location is mid-latitude Australian, plenty of sunlight most of the time)
- duckmysick 3y agoWhat do you use for hot water? Solar thermal collectors?
- originalvichy 3y agoI’d be curious to know if an inland Aussie would like hot water at all besides for cooking. Some nightmarish temps there.
- Andys 3y agoIt gets cold at night :)
- Andys 3y agoA 250L tank with a 3.6kW electric heater element, programmed to turn on when batteries hit 98% full (and off again when batteries fall below 95%). We really only use it for short showers, and it stays warm enough for that, for about 3 days without power.
- louwrentius 3y agoThat is really cool and would be my dream. In the Netherlands it's near impossible unfortunately to achieve 100% off-grid due to the winter months, when you basically have no solar. Maybe there are Dutchies who have somehow achieved it (with overprovisioned solar). Do you still have a grid connection for backup or are you 100% disconnected from the grid?
- Andys 3y ago100% disconnected; it was cheaper this way (grid was too far away). What is the typical kWh/day consumption of a household there in winter months?
- louwrentius 3y agoThanks for sharing. To be frank, I've looked in my Energy supplier app (Vattenfall) and it states for December an average usage of 122 KWh (all households) and energy efficient households (solar) of 91 KWh.
- Andys 3y agoNo problem, I'm happy to share all the info. People need to hear how easy it is to do this with the latest technology. 122 kWh per day ? That can't be right.. does that include gas or something?
- louwrentius 3y agoSorry, per month. So around 4 KWh a day on average. Gas is not included.
- zo1 3y agoI'm not OP, but I would look at this tool I found a while back. Ridiculously useful and underrated. I think someone on HN linked it, as I've not found a tool so useful via googling despite many attempts. https://re.jrc.ec.europa.eu/pvg_tools/en/ https://re.jrc.ec.europa.eu/pvg_tools/en/ What you're looking for is the "Off Grid" tab, plug in your details. e.g. solar array size, size of battery, etc. Then click visualize results. After visualizing, there are a few tabs to help you make some decisions. For your case (Netherlands, it looks like a 5.4kWp solar array and 4kWh (I assumed 5) used per day, and with a single 5kWh battery, you should be able to go off-grid :) In fact, during summery months, you could even push to the grid. This tool even looks at cloud data based on various databases. I don't know of it's accuracy, but I'm inclined to trust it.
- 3y ago
- skc 3y agoReally curious to learn more about this. Have you had to scale back usage of certain appliances such as irons, air conditioners, washing machines etc?
- Andys 3y agoAmazingly, no. I thought we were going to have to, but our natural usage peaks at about 20 to 30kWh per day, and we can generate far more than that on a sunny day. Thanks to the oversized PV array, we generate power even in cloudy conditions. The PV array is also split in half and oriented east+west so it catches more sun through the entire day instead of a midday peak. For things like clothes washing, drying, and hot water heating, those are the heavy users but can be moved to times of good sunlight. We only run out of power if we have 2 or more days of heavy rain in a row, which only happens a few times a year.