Brian on the solar control panel where you can tick to graph expected solar values can you add an option please to allow plotting a percentage of the expected solar values, so people can choose to plot say 75% of expected. I think this would greatly assist in setting the correct solar threshold for sunny as you could compare your raw solar values to any ‘sunny’ threshold you might want to try and see how it fits against a curve on a sunny day.
Stuart
BTW I’d like to be able to set the % value to be plotted on the same place as the plot button is now, I think it would be better to have a separate value for testing and then only change the actual threshold when happy with the % when compared to the graph.
I played around with this and found it helpful in setting my sunny threshold to match the actual solar readings. It appears that my readings on a sunny day are closer to the 80% mark for full sun. As I suspected, all the crap in the air is blocking 20% of the available solar. It will be interesting to see how this changes in the years ahead as we come up with ways to reduce pollution and clean up our act. Hopefully it won’t go the other direction #-o
True. But others have reported similar findings so I don’t think this is confined to my area. I think the northern hemisphere has much worse air quality than the southern.
I agree, since I got my Davis solar I have had to reduce my sunny threshold to 75% otherwise it was saying it was partly cloudy when there were no real clouds anywhere and the sun felt hot when you were out in it.
I thought there was something wrong with my VP solar sensor… the W/m2 never got much above 80% expected either. So I compared the output to Davis’s own station in Hayward (on a clear day around the Bay) and found I was only about 2-3% below theirs, so it’s not the sensor per se, it’s the ‘expected’ that’s a bit high for the area/time of day.
Thanks for adding the ability to adjust that Brian!
I can see now
bumper stickers:
my expected solar reading for the lat/long for the time of day is only 75% and it should be more than 80%, please drive a smaller car !
in NZ, the vast majority of cars are japanese
i.e 1.3 to 1.6 or sometimes 2.3 size litre engines
compare that to the big Dodge 8 litre cars/trucks/utes i saw lots of in the midwest!
Problem here is that the UK has a very high proportion of company cars and an awful lot of those are big, although not as many 3-5 litre giants as in the USA, most are 2 litres or thereabouts. Also quite a lot of people have fuel cards as well so that does not encourage careful or economic driving. Now I’m retired (or retarded as my son describes it) I do drive a 1200cc petrol car, and since I pay for my own fuel I’m more careful about how much I use
Brian,
I’ve installed WD 10.37f-build 12 and see the new ‘Plot this as % calculated’ option … I’m guessing that the ‘Always show max solar for time of day…’ has to be checked for it to work.
I do have a question about the ‘Attenuation (*10) finetune’ control … it seems to only allow values of ‘0’ … ‘5’ – what does this control do?
Ken the attenuation factor is the adjustment for the effect of the atmosphere reducing the intensity of the sun. Most of the available calculation routines on the web use this value, and in my view it should only be altered if you live at significant altitude where the atmosphere is thinner and has less effect of reducing the sun’s power. I suppose it could be increased to offfset the effects we all seem to be seeing. Over the next couple of days or so I’ll play with my solar calculator php script on which Brian’s code is based to see how changing it alters the expected values.
