East and West solar array

1

Hi guys,do any of you have a east and west solar array? I want to increase my solar array, but because we live on a mountain the front legs of my structure will have to be 5,7 meters long to get the correct angle. On a east and west array the angle is much shallower.

2

Can you do a N-E + N-W instead? I think that would be optimal for self-consumption, as long as you have enough MPPTs.

3

You donā€™t need more MPPTā€™s. As long as each string faces same direction you can have them on same MPPT. I have a east/west setup that does just as well as my north only setup and if I had to redo I would have just gotten one MPPT and put everything on it.

there is a thread on this already will try find it

edit: Solar panel direction East/West vs North

4

Your description is not very clear on what you mean exactly, but by having them all on one MPPT, you could be leaving a lot of kWhs on the table, depending on a number of factors like the MPPT algorithm.

5

Nope, you donā€™t.
If you study a panelā€™s VI curve, I is not proportional to V.
A panel attains full voltage under meager light.
I am going to explain this with a very extremist example.
If I had an identical E panel and a W panel. I am going to simulate a very extreme morning by covering the W panel with a blanket. The MPPT will still zero on the correct voltage based on the E panel.
Similarly, I can simulate an extreme evening and the MPPT will still deliver the correct max. power.
Now letā€™s consider noon, well, then both panels are delivering, and the MPPT picks a voltage that delivers the max power, which just happens to be spot on for both E & W panels.

So letā€™s consider the mid-morning when the E panel is at 75% power, and the West panel is at 25% power.
So the MPPT will favour towards the tracking voltage of the E panel, which will be slightly higher than the W panel, right?
This is where the VI curve comes in. You will see there is practically no voltage difference between the E panel at 75% I and the W panel at 25% I.
Keep in mind the tracking voltage will still be between these two voltages favouring the E panel as well.
It boils down to that it is a very efficient way to keep an MPPT working for longer in the day an not have to buy a second MPPT.
The low-hanging fruit is to buy extra panels with the saving you made by not needing a second MPPT. Thatā€™s put a lot of kWhs back on the table.

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6

Germany pioneered East West arrays on the same MPPT over a decade ago. The proviso being each array is the same size with the same electric characteristics (same model panels) and that the tilt is Ā± 15ā°. Losses are limited to about 10% of a South facing array (Northern Hemisphere).

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