Solar panel and shade, best setup help

[Frank in Thailand]

Hi there!



One picture tells more then a hundred words

Thailand has the sun directly above our heads so the overhang of the roof casts a shadow.

Sunrises on the right, and sundown on the left.

Morning and later afternoon no shade.

I have 2 x 12 panels.
5 can be covered half in the sade.
7 would be sunny.


Will a shaded solar panel that provide the same voltage but half the capacity...
Say 150 watt in stead of 300w, will they limit the others to also provide maximal 150w?
So the choice is 12* 150w
Or loose 3 panels, and get 9* 300?

5 x 150 + 7 x 300 = 2850
Or 12 x 150? = 1800
Or 9 x 300? = 2700 (not using the shaded space)

Shading starts around 10.30 and stops around 14.30

This 40% shading is the maximum it will get

What is the best way to install?

To add complexity, they can't be parallel. Inverter starts at 250v, max 450v.
6 x 36v = 216..
Minimal 7 panels in a string.

Mppt max capacity 3500

Thailand heat, angle, some dust, there will never be full performance of the 300w.
Say 10-25% less due to environment.

14 panels would be too much for one MPPT.
So giving one 14 and the other 10 isn't an option.
Well .. is, but will result in loss as the MPPT can't convert all the provided electricity.

Ideal it can produce 2 x 3500 watt
I like to get as close as possible to this maximal performance as possible.

What to do with the shade???
Not use the space (and not use 3 panels)

Or...

??

Your input is much appreciated ?

 

[efficientPV]

Not a lot you can do for shade. I have 60 to 70% of my panels in shade at any one time so I have six strings in parallel. My system can run on ambient light for the necessities.

When you have defined line shading like yours, the panels should be oriented 90 degrees from the way you have them. Internally the strings are lengthwise in three strings with a bypass diode for each string. The way yours are oriented any shade pretty much knocks out the entire panel. In the other direction you might have one or two internal strings producing full power but lower voltage. One long string with a MPPT controller can sort that out. Parallel strings will be a problem unless each string has identical shading. The controller will lock onto the string with the higher voltage. You have a big problem to sort out

 

[Frank in Thailand]

Yeah.. well not that big problem to sort out

Your input already helped. (A lot)

I have space for 23 panels.
And I have 24 panels.

If I orient 2 panels sideways it will work the "best" due the diodes.

Then I have 2 strings of 11 panels (2 x mppt)

To make it a bit more complicated..
18 x 345w panels
6 x 325w panels

I'm aware that the 325 will reduce the production of the 345.
Yet 7* 345 is 2415w
11 x 325w is 3575 watt.
Overall it's a gain

The 2 panels that are placed sideways...

Should they be the 325? Or better the 345 watts?

Or... Not use all together?
So keep the space open?

That would make it -3 panels.
2 strings of 10

1@ 10 x 345 = 3450
1@ 8 x 345, 2* 325 , seen as 10*325, 3250 watt

I just like to get the maximum performance out of the 24 panels available.

One area is 5*6 meter (15 panels)
The other area is 4*4.5 meter. (8 panels)

It's good if I can use many.
They are available.

It's OK also if it's better not to use them.

6700 watt should be just enough for our power consumption.
(Depending on the weather..
At +40c the air conditioning units are THIRSTY!)