How to determine best placement of ground mount panels in backyard?

Howdy,

I understand that I only get about 4.5 - 5.5 hours of solar peak power depending on the time if year for my area. Being that I want to expand my current system with adding 4-6 panels ( 4-400s watt or 6-300s watt ea. I will be using a SCC ) with a ground mount system, what methods should I take to find the ideal placement in the backyard? I do have the option to point south, south east. There are obstacles that can cast shadows more in the morning then in the afternoon, and limited areas that I can mount a system on the ground. South west there are some trees that will be to my disadvantage in the summer.

Do I mark areas that are in the sun at 10 AM and again 2 PM to see what I have an area that would be in that peak area? My house will cast a shadow in the morning.
However it is May and I would assume that will be much different in Dec. How can I account for that? Is 'noon' the middle of the peak solar time?

As always I thank you for your comments.

Google solar has maps that chart out building solar irradiance, nothing for ground mount, but perhaps there are shadow charts you can check? Aside from that, you would need a set of pictures showing where the shadows land through the year.

Supervstech said:

shadow charts

Click to expand...

Sweet, that may be the 'word thing' I need to put in the 'google bot' to get the answers I seek Half the battle is to know what to search on. Thank you.

I found this link with additional searches. You can change to a photo map, zoom way in and change the date. There is a time 'slider' where you can see the sun position, this is nice.

I made some measurements in the yard at different times of day & season to find a location for my Solar South facing ground mount.
Had to cut down 3 trees that blocked afternoon.
After some great advice from this forum, a year later added some West facing panels to pick up energy in the late afternoon.

These are some sites I used to determine tilt and direction.

Confusion for me was: Some show degrees relative to vertical, some show degrees relative to horizontal.

Helpful, after I figured that out.
http://www.solarelectricityhandbook.com/solar-irradiance.html

@Lost_One I used that site a lot in the planning of my 45kw system (still working on installation). Make sure you check things around your property and check winter/summer solstice. We have a large swing in sunrise/sunset locations here, so it is tough. Best of luck!

There is not one single best solution to this question.
First, decide what is most important to you, max overall harvested power, or max number of hours of solar.

If you have a large battery, a massive power peak at solar noon can usually be easily absorbed.
But if there is no (or very little) battery storage, less power spread over more hours of daylight might be a lot more useful.

In a very cold climate, you probably need a lot of power early in the day for battery recharging, and breakfast time ! So easterly facing panels might be preferable.
In a very hot climate, airconditioning might dictate westerly facing panels for power in the afternoon and early evening are best.

If you get a lot of really grey gloomy total cloud cover days, panels facing straight up will always give more than any other direction.

So take into account your climate and local weather, and power requirement through the day.
You cannot have it all, but a bit of planning and some trial and error might pay off.

I have four groups of panels.
One group face due north with sixty degrees of elevation. They face the sun directly on mid winters day.
A second group also faces due north but are almost flat with fifteen degrees elevation. These work well on very cloudy days.

A third group has panels facing due east and due west with sixty degrees of elevation. These start up at dawn and give good constant power right throughout the whole day, until sunset. These get going at least an hour before the main north facing panels in summer when the sun actually rises behind the north facing panels. They do the same thing supplying power late in the afternoon.

After about five years of operation I am pretty happy with the whole thing as it is. If I ever add any more panels, they will probably be facing straight up for additional power on total cloud cover days.

Warpspeed said:

max overall harvested power, or max number of hours of solar

Click to expand...

There is a lot of overall info packed into this post. I already have roof mounted E and W facing panels so S seems to be the best choice for me. Being that I am looking at a ground mount system, I believe that you have brought up some good point that point me to the more expensive single pole, top mount where I can adjust the tilt and E to W for seasonal adjustments. I have been looking at the MT Solar mounts, but the cost is very high, but I can adjust the tilt and if needed move more E to W as necessasy.

If you can do a bit of data logging over a whole year, it will give you an excellent overview of which panels work best in different situations, and you can then mount any new panels in a direction that will be most useful.

pvdude said:

I made some measurements in the yard at different times of day & season to find a location for my Solar South facing ground mount.
Had to cut down 3 trees that blocked afternoon.
After some great advice from this forum, a year later added some West facing panels to pick up energy in the late afternoon.

These are some sites I used to determine tilt and direction.

Confusion for me was: Some show degrees relative to vertical, some show degrees relative to horizontal.

Helpful, after I figured that out.

Optimum Tilt of Solar Panels

http://www.solarelectricityhandbook.com/solar-irradiance.html

Click to expand...

regarding the direction to point, I see many of the PG&E utility company remote control systems have the pole-mounted panel pointing about 200-240 (SE-E) rather than directly south... I guess the thinking may be that if there is fog or some weather, it is more likely to burn off by late afternoon and good to point this direction to catch the few good sun hours that might be left near the end of the day...
I have been thinking about recycling the 12x10 ft dog kennel as the ground mount....

and many of the homemade ground mount I see here will be blown away at some point, maybe think about using a connector that will give way in that event and uncouple rather then torn off and short out...
regards

One reason to face panels east or south east is for battery charging.
Early in the bulk charging cycle, current will be at a maximum, the battery can accept everything that is available.
As the battery reaches full voltage, the charging current tapers off throughout the day.
By afternoon, there is no advantage in having excess solar.
What you need is big power early in the day when its most useful for battery charging.

here is what I did for my ground mount.
ground mount pics

ko6kL said:

regarding the direction to point, I see many of the PG&E utility company remote control systems have the pole-mounted panel pointing about 200-240 (SE-E) rather than directly south... I guess the thinking may be that if there is fog or some weather, it is more likely to burn off by late afternoon and good to point this direction to catch the few good sun hours that might be left near the end of the day...
I have been thinking about recycling the 12x10 ft dog kennel as the ground mount....
View attachment 102580
and many of the homemade ground mount I see here will be blown away at some point, maybe think about using a connector that will give way in that event and uncouple rather then torn off and short out...
regards

Click to expand...

here is one way to do it cheap

added some tilt to the mount, see detailed photo, it's a make-your-own shelf bracket from the hardware store... hose clamps to frame.


Birds like to land on that little wood part in the circle , i hope to take many bird photo's here
and bring up during planning meetings regarding zoning for solar.... birds like it!
getting about 90AH a day in the overcast skys we have here.