Solar Performance LUX Measurement

[CA_Traveler]

Solar performance discussions on these boards often have phrases like “overcast day”, etc. I’m wondering if one of the inexpensive phone apps would lead to a better understanding of panel performance. Of course these apps are not as accurate as professional meters but they could help to gain a better understanding of light levels.

Has anyone tried this LUX app which cost $2 for example? And how about apps for other phones?

[MEXICOWANDERER]

If, and this is a biggie, you can access quantatative information at Sandia National Labs, qualifying measurements of solar to voltaic panel cell response an accuate idea will emerge re: LUX and cell productivity. You can also try and work up a Trends & Tendencies series of formulasbut LUX to panel output relationships can be misleading. Personally I would try to study a bit if information is available on the web. Optical illumination and panel cell photo response are two different animals. As an extreme example 1, 000 watts of LED illumination can be applied and it would not equal the energy of what is produced in the middle of a fog bank. Conclusion: Double and triple check assumptions.

[JiminDenver]

I have a free light meter on my phone and plan on the same thing. Like the sound meter I have no idea how accurate but it gives me a base that I can tell when things go up and down.

I believe this is the one I have. Free light meter

[MrWizard]

I have two LUX apps on my phone
How they compare to the one in the link...IDK

What I did was use them to compare readings between fluorescent ceiling lamps..And LED ceiling lamps

Side by side readings turning the lamps on and off , phone at waist height beneath fixture

No way for me to calibrate to a known source , to make lux to watt readings

I like the idea...read the lux at the panel..then record the watts from the controller out Turnigy meter

The next time I get out the telescopic ladder and get on the roof
I might do that
But it will only be relative , because I don't have a dedicated calibrated lux metre