Setting center angle for solar panels

Just add more panels. It's a pain climbing the roof and changing the angle. Roof is slippery and you need to step carefully because it's not too strong, and panels are heavy even if you lift only one side, and re-attaching those pins or nuts in support struts is a pain when you can only reach one strut at a time. Besides, if your panels can only be tilted but not rotated, it's not always possible to park with tilted panels facing South, so then you'll have to lay them flat.

I also agree with what Redsky says - try and consume less. 30% of maximum daily output is nice because you'll harvest less than half of max output on some days, and sometimes - less than 20% of the max. If you max harvest is 3 times the consumption, your batteries are really full, meaning Float, by the end of the day. Also, if it's clear in the morning and cloudy later, those afternoon clouds won't bother you because you've managed to charge it before noon.

If you are only using 30% of your solar output why are you reducing consumption? I would be looking for more things to run so not to waste all that solar I paid for.

There is the mistaken notion that if the panels are not perpendicular to the sun that a great deal of light is lost. The solar panels' cells are designed to maximize the conversion of sunlight and to be as impervious to the angle of entry as possible.

There is not nearly enough of a gain in most situations to bother with tiling the panels as this would not only need to be done based on the latitude of the location but also based on the time of day. Commercial racking will have a computer control to track the sun and adjust the tilt and rotate the panels throughout the day.

I use less than 30% of my panels output and the remaining 70% is shunted away by the controller. Increasing their output by tilting would only mean that more of the output was being lost on any given day.

For my part I focus on reducing consumption inside the RV.

BFL13 wrote:


Many/most people say to heck with that, and just get an extra panel and nail them all down flat on the roof and stop obsessing about the
stupid solar. That's cheating! :)

If you seriously can add just one panel and avoid all the hassle, sounds like a plan to me.
bumpy

Or build/buy a tracking $ystem so one never has to mess with it, but that would require $ome ca$h.

mena661 wrote:

BFL13 wrote:
http://www.macslab.com/optsolar.html

Good link. I think I can actually understand that.

That link is for panels pointing South tilted up to get the most AH per day. It does not apply to panels that can be pointed at the sun all day.

With fixed South panels, your optimum tilt is less than best tilt at noon as shown in the link. With tracking panels it is the other way around. Noon is the lowest tilt because that is when the sun is highest during the day.

In all cases the aimed tilt is 90 degrees - sun's altitude. The sun goes up and down each day, plus it goes up and down over every six months as the Declination changes approx. 46 degrees between the Earth's equator and the sun's ecliptic.

This means the best tilt at noon changes about 8 degrees a month or 2 degrees a week no matter where you are in latitude. If you want to stay on top of things and get the most AH for your solar buck, you have to keep up!

Many/most people say to heck with that, and just get an extra panel and nail them all down flat on the roof and stop obsessing about the
stupid solar. That's cheating! :)

During the Summer I leave my panels flat, no need to tilt.

BFL13 wrote:
http://www.macslab.com/optsolar.html

Good link. I think I can actually understand that.

Another way to accomplish good tilt angle is to use the best insolation angle in Winter, choosing both MN and FL as tilt points, using either angle when in those locations. A user could also set tilt for best insolation to his locality.

In Summer, you can choose the best insolation angles (another set of tilt points) or leave the modules flat as your harvest duration is much increased.

I have mine set at 59 degrees for Winter storage in MN and leave it flat when on the road.