Bluedog225
Texas
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Used my iPhone 13 compass to line up my first array due south.
Well done.
Well done.
Last edited:
iPhone fail-compass
- Thread starter Bluedog225
- Start date
Andrewr05
[Replicant 42069]
Is there a calibration option?
Also, I'm not even one who usually worries about this kind of thing, but I would be leary without posting your full exact GPS coordinate location out for everyone to see.
Also, I'm not even one who usually worries about this kind of thing, but I would be leary without posting your full exact GPS coordinate location out for everyone to see.
Bluedog225
Texas
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Thanks! That did not occur to me. Will edit.
Bluedog225
Texas
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I only had the one phone out when I placed the posts. The bobcat and post drive were out there and I had to get it done. I’m generally south based on sunrise and sunset. I’ve rationalized my easterly bias as being what I wanted all along.
Haven’t seen the calibration deal on the phone for a few years. I remember when it used to ask you to waive the phone around for a bit.
When I first fired up both phones, they were about 180 degrees different. Then came into agreement over the course of about 5 minutes. I’ll have to check the true north vs. magnetic.
Haven’t seen the calibration deal on the phone for a few years. I remember when it used to ask you to waive the phone around for a bit.
When I first fired up both phones, they were about 180 degrees different. Then came into agreement over the course of about 5 minutes. I’ll have to check the true north vs. magnetic.
ricardocello
Watching and Learning
Magnetic calibration of the internal sensor needs lots of phone movement in swirling patterns like a figure 8 for 30 seconds or so.
There is a theodolite app I use that gets pretty darn close. Do watch out for magnetic or true, you want true.
And stay away from any iron or ferrous materials, do it in free space.
There is a theodolite app I use that gets pretty darn close. Do watch out for magnetic or true, you want true.
And stay away from any iron or ferrous materials, do it in free space.
Q-Dog
¯\_(ツ)_/¯
I did that, plus found "solar noon" for my location and used that. Then I double checked my results with the overhead internet map view of my house.Or better still...
You could just put a stick in the ground and see where the shadow falls at midday
Use Google Earth or Maps (in sat view) to see what south aligns to on your property and use that as a reference. Do not depend on a compass due to variation in magnetic versus true heading, and the fact compass are subject to local variations.
The sun at clock noon doesn't really work due to time zone variations. You can adjust this for "solar noon" using a website like this:
It will give you the time in your local time zone of precise solar noon. Then mark that line.
You should also consider your use curve. If you are using more energy in the morning, bias the array slightly east. If you use more energy in the afternoon (like heavier AC use in a warmer climate), then bias the array slightly west.
Mike C.
The sun at clock noon doesn't really work due to time zone variations. You can adjust this for "solar noon" using a website like this:
ESRL Global Monitoring Laboratory - Global Radiation and Aerosols
The Global Monitoring Laboratory conducts research on greenhouse gas and carbon cycle feedbacks, changes in clouds, aerosols, and surface radiation, and recovery of stratospheric ozone.
gml.noaa.gov
It will give you the time in your local time zone of precise solar noon. Then mark that line.
You should also consider your use curve. If you are using more energy in the morning, bias the array slightly east. If you use more energy in the afternoon (like heavier AC use in a warmer climate), then bias the array slightly west.
Mike C.
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... in case the sun got it wrong?
Q-Dog
¯\_(ツ)_/¯
No, in case I didn't do the stick pointing thing correctly.... in case the sun got it wrong?
ricardocello
Watching and Learning
Stick must be perfectly vertical, use a calibrated stick or a level!
Bluedog225
Texas
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Use a plumb bob on a tripod. Then you have gravity and the sun both on your side.
But don’t use an iPhone….
But don’t use an iPhone….
Brucey
Solar Wizard
Use the iPhone as the plumb
marionw
Solar Enthusiast
Also consider magnetic declination https://www.magnetic-declination.com/ to correct magnetic south to true south.
But ultimately for most it is what gives you based on horizons and other obstacles the largest solar window.
But ultimately for most it is what gives you based on horizons and other obstacles the largest solar window.
Q-Dog
¯\_(ツ)_/¯
My roof and property lines don't follow true NSEW anyway, so if I try to do true South nothing will line up with anything on the property, and I don't really have enough room to angle stuff too far off the property lines and house. I'll probably eventually end up with 2 arrays ... SSE and SSW. But finding the true South was helpful.
Bluedog225
Texas
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In fairness, it was only 77° off at the time of the photo.
teal95
Solar Enthusiast
In MI solar noon is around 12:50. All of Ohio should really be on central time.
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