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Sun tracking solar panel mount/kits.. why are they not more common?

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beowulf

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I am curious about the use of sun tracker setups.. where you mount 2, 4 or more panels on a typically I would assume cemented in to the ground module for balance (esp against wind). I see a few on Amazon for like $500, and then there is the Ecoflow for $3300. I am sure there are more out there.

They supposedly give an addition 40% or so energy throughout the day per panel.. likely in ideal weather.. but even so, given the relatively "cheap" cost and space savings.. why am I not reading more about this? Is it purely that roofs could not support any sort of even partially tracking module to adjust panels even 15 or 20 degrees over a few hours? But for sure off grid folks.. wouldn't it make sense to set up a couple of these units for the say $1000 for holding say 6 panels to pick up an additional 20% to 40% more energy per day? Or is it just way too much work to install, and they really dont work that well? Maybe they are not very durable and dont last more than a few years before you'd have to replace the motors/etc?

Love to know if there exist some quality units that would last 20+ years with minimal upkeep/maintenance or if these things are very easy to break down and costly to fix?
 
I have a ground mount install but I'm usually not a fan of adding moving parts to a system which is subject to harsh weather conditions at times. I've always felt like a tracker system would come with lots of maintenance requirements and would give me hard time every now and then. Maybe I'm wrong but I kinda feel I'm right.

I agree with the space argument and adding panels is a much better alternative (again, no moving parts :). But if space is limited, then it could be a different story.

So it would indeed be interesting to read some comments from people who actually use tracker systems.
 
beowulf said:
But for sure off grid folks.. wouldn't it make sense to set up a couple of these units for the say $1000 for holding say 6 panels to pick up an additional 20% to 40% more energy per day?
Click to expand...

The added complexity (moving parts), them freezing in winter, maintenance, etc. Just not worth it. I just add more panels, like on my newly built woodshed. Easier, cheaper, less things to go wrong.
 
Too windy at my location. Fitted a motor to a satellite dish many years ago, the constant gusts worn out the gears within 2 years giving too much backlash. I wall mount and adjust vertical angle twice a year.
 
I prefer just having a seasonal adjustable mount, it snows here and I want those panels tilted more in winter. You do gain some yield with more tilt in winter, it comes out to less than 3% according to what PV Watts shows when comparing a 47 degree tilt to a 66 degree tilt for winter months. The main advantage is snow won't lie on the panels for long periods of time, that's important if you are not grid tie.

Tracking devices come with additional costs upfront and ongoing costs once installed. If you had a very limited area to install an array, it might make sense. Given I've seen panels under $0.50/watt, it really doesn't pay to have trackers. Seasonal tilt does pay, you really only need to move tilt 4 times a year.
 
I would like to see a relatively low cost commercially available single axis tracker like the beauty that @BradCagle cooked up in the video below.. Multi-axis tracking seems excessive and like it would break too often.

 
Agreed. Just something that can rotate one axis from morning to evening, then reset. Be great if it was handle cold weather as well and use the power from the panel itself to power the motor + tracking details.
 
That is slick.. but now you need panels to put out enough power to rotate a bigger motor.. that ALSO has panels putting power out to a MPTT so that you actually get power from it. :D
 
beowulf said:
That is slick.. but now you need panels to put out enough power to rotate a bigger motor.. that ALSO has panels putting power out to a MPTT so that you actually get power from it. :D
Click to expand...

On this little one, maybe we could use some sort of timer, so it only checks every now and then.. and switches the output of both panels out to an MPPT when not checking. So you only need one motor, big enough for both panels, and it just checks every 5-10 minutes or so? 15-30 minutes?
 
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KITROBASKIN said:
Seems like we have seen data that shows changing panel tilt twice a year is pretty good, with 4 changes per year not that much better?
Click to expand...
It is about 3% in winter months for the most part but not having snow on the panels ensures yield on days the sun is shining while fixed still have partial shading that kills production. Around here when it is cold in January, it also has clear skies. I've seen fixed panels have snow for a week around here so that is one week of lost production. Rooftop is worse around here, I drive around and take note of how long roof mounts are covered. I've seen some as long as 3 weeks. Those were all grid tie, if you ask the owners they will tell you their bank is depleted by mid January.

I've always taken PV Watts with a grain of salt. For one, you can see some months at a fixed 47 degree angle are lower than the previous, then a big increase the next followed by a much lower yield the next. For example, March at 1034Kwh, then April at 962Kwh, May at 1018Kwh, June at 992Kwh, then July at 1104. While the sky is clearer in March and there can be more rain in April, the May, June, July numbers really don't make sense. If you look at 30 degrees, the numbers seem more believable as you see a climb up and down centered around the summer solstice. Another thing is a 30 degree fixed out performs 65 degrees for a full year by well over 10 percent and this is at 43 degrees latitude. I've ran the numbers about every which way from 30 degrees to 65 degrees. I don't know how the data was collected to arrive at these figures, is it possible in winter snow covered panels some days or did they clean the panels off? I did compare December at 30 degrees compared to 65 degrees and that would be a 15% increase using 65 degrees compared to 30 degrees.

It does give a guideline on production but I certainly wouldn't say it is gospel. I'll keep collecting my data, I just use PV Watts to help size a system for production in the winter months and consider that into calculations. I would certainly oversize as it does give options to shift some loads. In my case, the projected yield for December using PV Watts is 53% more than my average usage for that month.

One thing I do have is historical power usage back to December 1, 2021 and noticed today that year over year, we had a decline of 150Kwh usage in December for 2022 compared to 2021. I asked my wife when she purchased the new refrigerator but she claimed it was before we monitored usage. January and February were down too but in March we went full micro grid for the house and started heating with it using resistive heaters. I won't know until next March how the heat pump compares on usage.

I would size an array based upon the usage for December and how much buffer one desires. Or for people farther south that have higher usage in summer months running air conditioning, it should be based upon the highest usage month. We produce way more than we can use in summer, I'll have to start adding more dump loads to take advantage of the excess.
 
beowulf said:
I am curious about the use of sun tracker setups.. where you mount 2, 4 or more panels on a typically I would assume cemented in to the ground module for balance (esp against wind). I see a few on Amazon for like $500, and then there is the Ecoflow for $3300. I am sure there are more out there.
Click to expand...

Basic math, get another 1000 watt of solar with zero maintenance for the price of a tracker and always generate more power
 
When panels were >$1.50 per watt they made sense. When you can get panels for under $0.60 it is just unnecessary complexity save a few very specific situations.

I know of a couple remote mountain top radio sites that have an average demand of about 600W and run two small wind turbines and two 400W panels on separate trackers. Their rationale was that they could do an initial helicopter lift for the equipmen, but upkeep is all hike-in/hike-out. They wanted to do anything possible to minimize the use of propane or have to replace a battery early, so making sure the batteries were used as little as possible was important.
 
KITROBASKIN said:
Seems like we have seen data that shows changing panel tilt twice a year is pretty good, with 4 changes per year not that much better?
Click to expand...
I ran the numbers using PVWatts and after buildin, did actual tests with my array, playing with the tilt angles and how often to adjust it:
Tilting 30/65 once every Spring once every Fall increases my solar overall about 8% for the year, however the change is primarily found Nov-Jan when I need it most, and I need the tilt to assist with snow removal.
Tilting makes snow removal simple - most of the time a bit of wind self-cleans the panels.

Adjusting one array every month, a few degrees at a time while the other array was only tilted spring/fall resulted in really no noticeable difference to the solar collection from each that I could tell, maybe 1%. - so I don't bother with "excess-tiliting" anymore.
It could be automated I suppose, but with freezing/ice build up, I would worry something will break.
If I didn't have snow, I wouldn't tilt the arrays, I would just have more of them.
 
I agree buying more panels can be cheaper/easier. But space, if you don't have the space for more panels a tracker is a viable option.

And also consider bi-facial on a tracker. I need to try this
 
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