On Monday, 19 August 2019 21:48:05 UTC+1, Chris Green wrote:
Andy Burns wrote:
Chris Green wrote:

I can't find a site providing what seem
to be realistic 'ball park' figures for UK regions.

http://www.reuk.co.uk/wordpress/solar/solar-insolation/

What I *actually* want to know is the 'average over the year' *watts*
from a panel.

It's more comlex than you seem to appreciate.
Where abouts do you live I'm guessing a panel is scotland might be differnt from that in cornwall, then there's the angle, is it fixed or what direction does it face, or perhaps it'll be directional and controlled.
Then there's the panel itself, there's differtn types and they age too and depending on how hot they get that will also change it's effcicincy and useful life.

I've seen this with students they calcluate what they'll get from a 12V panel, which is normally spec'd for far higher light levels than we get in the UK, they bring it into the lab expecting 12V at say 3 amps and they end up with 6V and milliamps (because of indoor lighting too).



I could work it out backwards from the above but a
simple "you'll get about 20% of the panel rating averaged over the
year" would be more useful. I want to know how much panel I need to
install to run a water pump, or how big a water pump I can reasonably
power from a 260 watt panel.

Do you expect the water pump to run at night ?




--
Chris Green
·