• eleitl@lemmy.zip
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    3 days ago

    Still need the grid as in winter months output is low. So 6 kW solar and 20 kWh battery is rather unbalanced.

    • humanspiral@lemmy.ca
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      3 days ago

      Doubling the budget is doubly the monthly electric bill. An EV getting a free monthly fuel bill 10 months of the year, is also a winter resilience device to charge the home with a trip to commercial charger. Majority of low income countries, topic, are concentrated around equator and lower seasonal variation. Rainy season in summer often means more winter than summer production.

      • eleitl@lemmy.zip
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        2 days ago

        Whoops. I got it wrong, sorry. If we follow Victron’s recommendations (4.8 kWh backup for 1.5 kWp generation) than for 6 kWp the LiIon backup (AC-coupled) would be pretty exactly 20 kWh. So your numbers are perfectly balanced.

        The problem with just scaling up is that in winter months I can easily see 1/20th to 1/40th of PV nameplate during daytime, and such conditions can persist for more than a month. So without the grid as a backup the only option is diesel generation backup, or going entirely without any major power drain.

        For low-consumer countries in the tropics the equation is much easier, since they’re consuming less than Westerners in general.

        • humanspiral@lemmy.ca
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          2 days ago

          A model for Canada, does require enough solar for just 1 hour total sun to meet electricity needs (for winter). Backup heating necessary, but hydronic and heat pump (reversible heat/AC split units per room) is good use of fall solar to charge up a hot water reservoir that also gets recharged on sunny winter days. An EV that can charge the home counts as a backup heat source. This can mean much higher solar production for 9-10 months than you can use, but also means profitable bitcoin mining or GPU rental for that period. And/or free EV charging, hottub/pool heating, or other energy sinks that become free, off grid.

          Canada/Ontario has corrupt electricity system, with $50/month flat fee. So a $50-$100/month equivalent (5x above investment) off grid cost is a better energy opportunity/alternative especially including vehicle fuel savings, but also in new construction heating system cost savings. A fireplace or woodstove may be an arguable quality of life improvement, instead of just a heating appliance.