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I do something similar to that. Living off-grid and my solar setup is quite small (1.6kwh of solar panels and a bunch of batteries). However I depend on electri

I do something similar to that. Living off-grid and my solar setup is quite small (1.6kwh of solar panels and a bunch of batteries). However I depend on electricity for most things, including cooking(induction) and hot water (electric water heater/tank). So in sunny days I let the water tank heat as much as possible(usually around 70-80C), and can go 3-4 days without even needing to turn it on. We are 4 in the household and it holds nearly 100liters of water. It is a kind of battery :)

WalterBright 7y ago
> It is a kind of battery I find it ironic that this sort of thing is so overlooked with solar/wind power on the electric grid. Consumer electricity prices should be allowed to rise and fall with the availability of solar and wind. Then, you can heat one hot water tank only when electricity is cheap, and also use that tank to heat your house in winter. In summer, a separate tank can be chilled when power is cheap, and used to cool the house. Or even simpler, a pile of rocks will work. With such a scheme, the need for grid batteries would be reduced enormously. Instead grids have the problem of what to do with the extra power when there's too much of it.
- nunodonato 7y ago
  well.. I guess water and rocks, at a scale that make them useful for other purposes will definitely have a size problem for most people. While a battery (especially the new lithium ones) can fit in a drawer :)
  - WalterBright 7y ago
    Your dwelling, just as it is, has a lot of thermal mass that can be used as a "battery". For example, cooling it to the low end of the comfort zone when electricity is cheap, and letting it drift to the high end when it is expensive. For example, the power goes out around here often. I've noticed it can take up to two days for the house to cool down. The water in the hot water tank is hot enough for a comfortable shower for 3 days. Water/rock batteries are cheap as dirt, no maintenance, no fire risk, etc.
castratikron 7y ago
I don't have a source handy but hot water storage is really cheap, maybe an order of magnitude cheaper than a lead acid battery. Plus you have infinite cycle count.

WalterBright 7y ago

> It is a kind of battery I find it ironic that this sort of thing is so overlooked with solar/wind power on the electric grid. Consumer electricity prices should be allowed to rise and fall with the availability of solar and wind. Then, you can heat one hot water tank only when electricity is cheap, and also use that tank to heat your house in winter. In summer, a separate tank can be chilled when power is cheap, and used to cool the house. Or even simpler, a pile of rocks will work. With such a scheme, the need for grid batteries would be reduced enormously. Instead grids have the problem of what to do with the extra power when there's too much of it.

nunodonato 7y ago
well.. I guess water and rocks, at a scale that make them useful for other purposes will definitely have a size problem for most people. While a battery (especially the new lithium ones) can fit in a drawer :)
- WalterBright 7y ago
  Your dwelling, just as it is, has a lot of thermal mass that can be used as a "battery". For example, cooling it to the low end of the comfort zone when electricity is cheap, and letting it drift to the high end when it is expensive. For example, the power goes out around here often. I've noticed it can take up to two days for the house to cool down. The water in the hot water tank is hot enough for a comfortable shower for 3 days. Water/rock batteries are cheap as dirt, no maintenance, no fire risk, etc.

castratikron 7y ago

I don't have a source handy but hot water storage is really cheap, maybe an order of magnitude cheaper than a lead acid battery. Plus you have infinite cycle count.