The ratio between storage capacity and production power seems way too low, unless your daily consumption is ~10-15kWh and your batteries are over spec for harsh winter days (and then you’d need couple of sun days to recover). Are you sure about these numbers?

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duffpkg a day ago | parent [-]

In it's location the solar is very effective, the 4kw is the actual generation rather than a label rating. 100% full sun, no shade, no clouds. The array typically generates over 20kw per day. The house is pretty efficient and the weather is very nice both summer and winter. This is not an area with a harsh winter or summer.

Shade and clouds of any kind, even very minor, have a HUGE effect on the production of a solar array.

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pyrale 20 hours ago | parent | next [-]

London's latitude is north of Calgary.

I don't know how far south you are, but 15-20° of latitude has a significant impact on the effectiveness of solar, especially during winter.

	▲	duffpkg 20 hours ago \| parent [-]
		Absolutely. Clouds also have a profound effect on solar output, I think much more than people realize. I am not english but my understanding is that london has a lot of clouds.

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insane_dreamer 11 hours ago | parent | prev [-]

> 100% full sun, no shade, no clouds ... the weather is very nice both summer and winter

Are you sure you're in the UK?