I have 2 banks of panels on an L-shaped roof: one bank faces SE, the other bank faces SW (90 degrees to each other).

(For this season now, may change during summer?)
The SE facing bank has an angle of incidence of about 90 degrees with the sun between, say 10am-2pm, which seems like it would be pretty efficient. Then the sun starts to face the other bank more directly. But the angle of incidence here seems higher than 90 degrees, say 120 degrees.

Assuming this stays fairly similar during the summer, should the SW facing bank be angled more to bring the angle of incidence close to 90 degrees? Or it's fine where it is? And/or summer will naturally have a better angle - keep it as-is for summer months.

It's not that I need more energy (right now). But would like to squeeze every ounce out.

The angle gradually changes year round and will be specific to your lattitude. If you optimize it today, you may not get desired results during the summer.

quote:

The angle gradually changes year round and will be specific to your lattitude. If you optimize it today, you may not get desired results during the summer.

Ok. So, wait until summer and check angle of incidence again. If closer to 90 degrees, that's optimal. If still 120 degrees, then investigate further if changing the panel angle is beneficial.

Pthe them on axes with drives to always face the Sun? Probably impractical. Most folks just mount their panels to face south all the time and don't worry about it. The panels will give some power even just from the sky.

flashguy

I have excess panels so the most efficient angle isn't necessary for me. That was a design choice so, if needed, I only have to move the panels twice a year. Considering I am only using an average of 17% battery capacity in 24hrs year round, I could get away with not moving the panels, but moving them and being more efficient will extend my battery life. I am at around 50* in winter and 30* in summer based on 0* being perfectly flat.

Many folks use the general rule of latitude + 15* in winter and latitude - 15* in summer.

Here is a good reference https://sinovoltaics.com/learn...le-tilt-calculation/

Unless it's stupidly easy to access & adjust the panels, it's probably not worth your time to fool with, especially on a backup/cogeneration system.

Sigolicious has more of an incentive to do it since it's his only supply.

Assuming this is fixed in place, the installer should have factored your seasonal need for power, and possible interference (buildings, trees, etc.) into the angles.

Our CA house was L-shaped and we were fortunate in that the long part of the "L" had great roof area facing west. We blanketed that side with every panel that would fit...the other side (south facing) got some as well (we figured on CA's utility costs skyrocketing, as in the event, they did) but the west did the heavy lifting.

Most of our electrical needs were in the summer, and that setup got us a lot of solar power in the summer afternoons/evenings. The elevation angles were done by the installers so that the most direct angles were when the sun was high in the sky (i.e. summer).

We didn't fret about the angle-suboptimality in winter - Silicon Valley weather didn't call for much power then.

Thanks guys. Sig - interesting info and seems to align (no pun intended) to what I'm seeing / anticipating.

It's not easy to adjust the panels but I would request it of the installer if the set up is currently sub-optimal. But looks like it might be the best balance for the year.

I'm still getting used to this net metering thing. It seems that during the winter, especially on cloudy / rainy days, generation is minimal. In fact, on rainy days, I think we consume much more than is generated on that day. But on clear winter days, we generate a little bit of excess. So, expect that a winter month will be slightly net positive.

Anticipate that spring and fall (no rain, no AC) will be heavily positive. But that summer w/ AC will be closer to neutral.

Our system is in PA. We produce an excess for 8 or 9 months of the year. Zero electric bills at that time. Winter, with shorter days and snow on the panels - they don’t produce enough and we get a bill each month. 11kw system.