To get the maximum sunshinethe correct direction for your solar panels is either True North or True South.
This is true North for people living in the southern hemisphere like Australia.
True south for those who live in the northern hemisphere like India.
True south and true north are also referred to as True South and True North, respectively.
These are collectively called geographic poles.
Read: How to find the right solar tilt for maximum sunlight?
Magnetic poles and geographic (true) poles are different
The magnetic compass does not point to the geographical poles of the earth.
It points to the magnetic poles of the earth.
Magnetic poles and geographic poles are two different things.
The magnetic pole that is near the geographic south pole is actually the magnetic north pole.
A little confusing!
Let me clear things up with an illustrated example.
Our earth behaves like a magnet.
You can see that the magnetic pole near true south is Earth’s magnetic north.
In terms of magnets, opposite poles attract.
This means that the north of the magnetic compass is the magnetic south of the earth.
Likewise, the south of the magnetic needle is the Earth’s magnetic north.
Simply put, magnetic compass north is attracted to the earth’s magnetic south which is close to the earth’s true north.
Magnetic field lines always run from north of a magnetic pole to south of the earth’s magnetic pole.
While on the other hand,
The geographic north and south poles of the earth are the points from which the axis of rotation of the earth passes.
The earth’s axis of rotation and the line joining its magnetic poles are not aligned.
(The green line and the red line are not aligned)
Note: even if it is the opposite. Yet we take the direction of the magnetic compass needle as the direction of the Earth’s magnetic pole.
Why are these two lines different?
Because these two come from different mechanisms.
Magnetic field lines come from inside the earth.
This is due to the circulating current produced by the molten iron inside the earth.
Earth’s magnetic fields continually change relative to its geographic poles.
These are due to changes in the magnetic flux in the Earth’s outer core.
While on the other hand, geographic poles are the points around which our earth revolves.
The magnetic poles of the earth due to the changing magnetic field may or may not align with true north or true south pole.
This is the reason for the difference between magnetic and true poles.
How to find the direction (True North or True South) of your solar panels?
The magnetic compass alone cannot find it.
We have to use a combination of the methods to get true north or true south.
Let’s discuss one of these methods.
a) Using the magnetic declination and latitude of your location
Magnetic declination is the angle between True North and Earth’s Magnetic North.
This is represented in the image above by θ.
The magnetic compass gives me the direction of the magnetic poles.
So somehow I get to know magnetic declination.
I can then rotate the compass by the magnetic declination value and get true south or true north pole.
Take a magnetic compass and line it up along the North and South point.
You will get the magnetic poles of the Earth.
Now find the magnetic declination of your location.
There are websites that can help you with this.
I refer to NOAA website to get magnetic declination values.
If the magnetic declination for your location is west, rotate the compass clockwise the same number of degrees of declination.
If the declination is east, turn counterclockwise.
Let’s understand it with the help of an example.
Suppose your location is in New York.
The magnetic declination of New York is 12° 38′ West.
Now to get True North in this case.
First, align the needles of the magnetic compass along the North and South points.
Then turn the compass clockwise at 12° 38′ to obtain true north.
(Note: The Magnetic North Pole is at 83°06′N 117°48′W in 2005).
For New Delhi, the magnetic declination is 1°16′ East.
Now that it’s east, gotta turn my compass anti-clockwise over there to get the true north or south line.
Let’s see the magnetic declination of some of the world’s major cities as of October 21, 2022.
- Tokyo (Japan): 7° 49′ West
- São Paulo (Brazil): 21° 43′ West
- Shanghai (China): 6° 26′ West
- Berlin (Germany): 4° 42′ East
- Bombay (India): 0° 7′ West
- Istanbul (Turkey): 5° 58′ East
- Buenos Aires (Argentina): 9° 45′ West
- Lagos (Nigeria): 1° 32′ West
- Cairo (Egypt): 4° 45′ East
- Mexico City (Mexico): 4° 7′ East
- Manila (Philippines): 2° 36′ West
- Canberra (Australia): 12° 34′ East
b) Using the shortest shadow method
This method is based on the principle that when the sun is at its highest point at noon.
The shadow formed is the shortest.
The line joining the ends of the shadow is the true North/South line.
- Choose a day when the sky is clear and the sun is shining.
(Wait until 11:10 a.m. for the sun to rise).
- take a stick
- Mount it directly on a flat surface or on the floor.
- The sun will cast its shadow
- As the sun rises, the position of the shadow will change and its length will begin to decrease.
- To get the shortest shadow length, after a few minutes, start scoring at the end of the shadow.
- When you observe that now the shadow begins to appear longer than the previous one.
- Stop the activity, the previous one is the shortest shadow.
- Join these ends, you get the True North/South line.
We should point our solar panels towards true south or true north.
For people living in the northern hemisphere like India. Keep your solar panels facing the true south direction.
And for people in the southern hemisphere, they should face their solar panels in the true north direction.
This improves the financial feasibility of the solar energy system and makes it more attractive.