Never sized a solar panel, but worked in the industry (basic research). I did tell a local manufacturer that they sized an array wrong for a particular inverter and that's why the system was for show and never worked.

I did design a system to do a demand side management study for that same installation hence the troubleshooting of the inverter. I didn't build or operate the system. I just designed it in a big hurry. The published study was done remotely, pre-internet.

Yes, the standard is AM (Air Mass)1.5 Global spectrum. https://en.wikipedia.org/wiki/Air_mass_(solar_energy) 100 mW/sqcm or 1000 W/m Clear day around noon in most places. Short circuit current is proportional to intensity,

OK, your right, crap shoot. You need a calculator e.g. http://solarelectricityhandbook.com/solar-irradiance.html
which can tell you on average how much solar energy your panel should get per day based on location, direction and angle of the panel.

Thanks for that, it makes sense.
Using the calculator theoretically the 100 Watt panel I was considering would do the job if
1. it was a genuine 100 watts output. The panel dimensions work out to about that so it might be OK.
2. I had some sort of battery storage to extend the usage during daylight as there would be an excess of power at midday and not enough in the late afternoon.
Interesting...
Maybe I will an consider battery storage upgrade at a later date.

 

My dental office has panels that look like this https://www.usaskypanels.com/products/cumulus-ii-skypanels.html on his florescent lights. Then, for fun, you could use something like these https://www.decorativelightcovers.c...ht-covers/astronomy-fluorescent-light-covers/ at night.

Interesting idea.

 

Solar panel specs are marketing tools - basically optimistic lies, with plausible deniability.

I would say use 30% of the rated output as a reasonable guess, but I would be more concerned about the behavior of the system as the light falls off.

Will it flicker or blink in a super annoying manner?
Test the light with a variable power source first- avoid a nasty surprise.

I agree 30% Is a good optimistic number.
Sparky