Panel angle optimization

[oakdale]

I've looked at optimizing the angle of tilt for solar panels before, at one time I picked two locations on insolation charts and interpolated the data for each month to match my location. Today I found a webpage that shares a way to use your latitude with three equations to quickly get a result.

the equations:
Winter angle = (latitude * 0.89)+24
Spring/fall angle = (latitude * 0.98)-2.3
Summer angle = (latitude * 0.92)-24.3

results for a latitude of 35 degrees are:
winter = 55.15 degrees
spring/fall = 32.0 degrees
summer = 7.9 degrees

They claim that these angles are optimized for producing power thoughout the day, not just at noon.

(My interpolated results were within three degrees of their winter and spring/fall results. I was ten degrees steeper with my summer angle. )

Their web page addresses more details than I've repeated here. It also includes simple charts with other latitudes. And they discuss the tradeoffs of fixed vs. adjustable mounts, as well as several other issues. I found it to be an interesting read.

Disclaimer: I have no affiliation with the company that produced the information and I don't believe that any of us would need their services.

[satguyjim]

This is the one I used: http://ocw.mit.edu/ans7870/SP/SP.769...t/PVPanel.html

[Naptown]

Personally I use the software from Solar Pathfinder. This takes weather into account to find the optimal tilt angle.

[russ]

Rich has the right software to do for the job and that is best.

For the rest of us PV Watts allows you to adjust the inclination (a bit) and is relatively good.

[oakdale]

by hand

My system is currently offline, need to buy more panels, a charge controller and batteries.

In the past, I'd manually adjust the angle to match the sun at around 11:30 am a couple of times a month.