Another solar panel question

Hi,

I collect 17 amp-hours on the winter solstice from 256 watts of panels. In the summer I get about 100 amp-hours per day. Location is 50.449197,-104.523339

jrnymn7 wrote:
I'm guessing going flat will yield next to nothing in the late fall / early spring?

jrnymn7 wrote:
I'm guessing going flat will yield next to nothing in the late fall / early spring?

In AZ he will do fine year round. This is not the Arctic Circle.

Crazy Ray wrote:
All 4 of my panels are FLAT I lose about 10%??? but I don't worry about the lost

not up north here in the fall, then it is closer to 30-40%. Down further south, and summer, yes not much different.

Optimum angle is roughly lattitude + solar declination. So, northern US. that 45degrees + sun angle which in the fall is 20 degrees or so, roughly 60 degrees. lay them flat or horizontal in those conditions and it drops of dramatically. A 45 degree error in orientation is a 30% decrease in solar energy.

Now optimum angle as BFL mentions is not constant since the sun traces an arc in the sky. so for static conditions you want it about the middle of the arc. Then for optimum daily gain, track the sun east to west. Neither is very practical.

But, even with a flat panel in the far north in the early spring or late fall, you will still get output. Could drop by 50% near the equinox compared to optimum.

Note that going horizontal has the same problem, it also is suboptimum for much of the year.

So.... since most of us like to camp, not fuss with the panels, pick your evil. flat panels on the roof that aren't optimum, or portables that can grow legs and need to be stored, and then get enough panel to do what you want. Or tilt on the roof with legs and crawl up on the roof. whatever suites your fancy. IMHO there is no ideal solution, what satisfies one person may not satisfy another.

jrnymn7 wrote:
I'm guessing going flat will yield next to nothing in the late fall / early spring?

Not sure what that means. The difference between flat and tilted is greatest when the sun is lower. The sun is lower daily and seasonally so it gets complicated. See macslab on "optimal tilt angle"

You also have the time early and later in the day in the summer when the sun can get behind the panel pointing South. After the March Equinox and before the Fall Equinox, the sun rises north of East and sets north of West so the closer to June 21st the more the sun can be behind the panel early and later in the day.

That is why your "optimal tilt" is less than the optimal for high noon, so you can get some shoulder hour time with the sun on the panel in the summer.

Note here where early the flat is better than tilted till sun gets higher.

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/26065604.cfm

It is all about the time to make AH from how that plays out and how they came up with an optimal fixed tilt for the whole day

I'm guessing going flat will yield next to nothing in the late fall / early spring?

2oldman getting ready to hit the Q ?

If wired in series you'll suffer greatly. Just came through casa Grande. Found the only casino in the western us that won't allow overnight stays. Up near Phoenix

All 4 of my panels are FLAT I lose about 10%??? but I don't worry about the lost

A special circumstance is if the panel is partly shaded by the AC shroud or something while flat, and a slight tilt would get it all in the sun. The tilt might not be optimal but results would be way better than a partly shaded panel.

Once you run out of roof real estate flat and still want more solar, then tilting is how to get some more.

Solar is cheap. If any doubts put two panels up there flat.