Manually adjustable tilt racking for large panels?

[missingegg]

Hi!

I've gotten a great deal on 8 LG NeON R 435W panels, and I'm now thinking about racking for them. These panels are 41"x75.2" (1042x1910 mm), and they weigh 45.2 lbs each (20.5 kg). I'd like to mount them in sets of two panels stacked landscape with a shared long side, on racking that's manually adjustable for tilt. I figure the weight of two panels (~90lbs) is manageable for me if I'm only lifting one side of the two panel set (I'm an old fart, no critiquing my muscle tone). And the landscape orientation implies two rails, going from low to high, and across the two landscape panels. I don't want to invest in a motor assisted tilting mechanism. I also don't think I need the efficiency gain of a motorized tracking system, a few adjustments a year should be fine for me.

I'm comfortable engineering my own DIY system and giving a few $$$ to a fabricator, but I'd happily pay for racking that would meet my needs. Is anyone aware of off-the-shelf racking designed for manually adjusted tilts with panels of this size? Google searches turn up racking at the low end, for single smaller panels, and the higher end with motors, but I'm not finding anything in the middle.

 

[solarsimon]

Have a look here - video shows detail

edit: forgot link

Cornish Rocker - an Adjustable Ground Mount by Solar Frames South West

A seasonally adjustable grounded mounted solar frame, the Cornish Rocker increases output by up to 40% in the Winter, is robustly built to withstand high winds and can be customised to your needs

www.solar-frames.co.uk

 

[DThames]

The total gain for seasonal adjusted tilt is pretty small. I thought about it for a while and ended up just building a fixed tilt mount.

 

[revbush]

Sinclair has nice ground mounts (https://sinclair-designs.com/Sky-Rack-2.0-Ground-Solar-Mount). Signature Solar has one that would also work.

 

[acdoctor]

The total gain for seasonal adjusted tilt is pretty small. I thought about it for a while and ended up just building a fixed tilt mount.

I disagree with Charles completely. I tilt mine. The single biggest factor I use to determine if I need to make an adjustment is production. When I see a noticeable drop 5 to 10 %. I make an adjustment. My maximum summer till angle to be perpendicular to the sun at solar noon is 5deg from horizontal. Winter is 56deg.

 

[Llaves]

The total gain for seasonal adjusted tilt is pretty small. I thought about it for a while and ended up just building a fixed tilt mount.

The page linked above explains the cases where it pays to do seasonal adjustment and where it doesn't. I did manual seasonal adjustment 4X per year for about 15 years because I'm offgrid and panels cost $4/W when I built the original system. I needed to squeeze every last bit out of the system. Panels now cost one-tenth of that. And if you're grid-tied, balancing winter/summer production is not an issue like it is for offgrid. My new system is fixed tilt because it's just not worth the hassle - just buy more panels.

If you're still not convinced, run your system through NREL's PVWatts calculator and see what you'd actually get in your location (lat/lon + weather). You'll need to run one calculation for each tilt, then look at the table of monthly outputs, picking the best tilt for each month.

If you're still determined to do this, there are pole-mount systems with crank tilt adjustment. You'll probably pay more for this than a fixed tilt system plus more panels to make up the difference.

 

[missingegg]

The total gain for seasonal adjusted tilt is pretty small. I thought about it for a while and ended up just building a fixed tilt mount.

Yeah, that why I don't think it's worthy the expense of a motorized tracker.

 

[missingegg]

Have a look here - video shows detail

I think you forgot to paste in the video link.

 

[missingegg]

I disagree with Charles completely. I tilt mine. The single biggest factor I use to determine if I need to make an adjustment is production. When I see a noticeable drop 5 to 10 %. I make an adjustment. My maximum summer till angle to be perpendicular to the sun at solar noon is 5deg from horizontal. Winter is 56deg.

Which racking system do you use, and would you recommend it?

 

[missingegg]

The page linked above explains the cases where it pays to do seasonal adjustment and where it doesn't. I did manual seasonal adjustment 4X per year for about 15 years because I'm offgrid and panels cost $4/W when I built the original system. I needed to squeeze every last bit out of the system. Panels now cost one-tenth of that. And if you're grid-tied, balancing winter/summer production is not an issue like it is for offgrid. My new system is fixed tilt because it's just not worth the hassle - just buy more panels.

If you're still not convinced, run your system through NREL's PVWatts calculator and see what you'd actually get in your location (lat/lon + weather). You'll need to run one calculation for each tilt, then look at the table of monthly outputs, picking the best tilt for each month.

If you're still determined to do this, there are pole-mount systems with crank tilt adjustment. You'll probably pay more for this than a fixed tilt system plus more panels to make up the difference.

For this particular installation, I'm severely space constrained, and the 8 panels I've purchased is as big as I can go. So changing the tilt is my only option for boosting the system's output, as I cannot put in more panels, even if someone gave them to me for free.

 

[Zwy]

Hi!

I've gotten a great deal on 8 LG NeON R 435W panels, and I'm now thinking about racking for them. These panels are 41"x75.2" (1042x1910 mm), and they weigh 45.2 lbs each (20.5 kg). I'd like to mount them in sets of two panels stacked landscape with a shared long side, on racking that's manually adjustable for tilt. I figure the weight of two panels (~90lbs) is manageable for me if I'm only lifting one side of the two panel set (I'm an old fart, no critiquing my muscle tone). And the landscape orientation implies two rails, going from low to high, and across the two landscape panels. I don't want to invest in a motor assisted tilting mechanism. I also don't think I need the efficiency gain of a motorized tracking system, a few adjustments a year should be fine for me.

I'm comfortable engineering my own DIY system and giving a few $$$ to a fabricator, but I'd happily pay for racking that would meet my needs. Is anyone aware of off-the-shelf racking designed for manually adjusted tilts with panels of this size? Google searches turn up racking at the low end, for single smaller panels, and the higher end with motors, but I'm not finding anything in the middle.

Just reviewed MT Solar. https://diysolarforum.com/threads/mt-solar-mount-review.51255/

If you are handy and have some fabrication skills, you could fabricate much of it yourself. I'd buy something along the lines of the Tamarack rail system to mount the panels but as for the mount and tilt mechanism, much easier to buy some long I beams, 10 feet of 4 inch pipe and 10 feet of another pipe that slides over it for a hinge along with some square tubing. I bought one for a few reasons, one was time, I'm still building my battery and finishing inverter and electrical install in the house. Snow load in winter that clears off days before fixed tilt in this area and lower sun horizon. I also wanted to be able to run the lawnmower under the array in summer.

My next array addition in a year or so will be a fabricated one similar to the MT with modifications for it's shortcomings or purchase the Skyrack 2.0 with tilt and mount posts in concrete. I have the large earth auger after installing the MT Solar mount so not a huge deal. I do like having the array higher in the air, not so many problems with shading as a result. Can you believe there is a building that is 26 feet tall at the peak southwest of this array by about 45 feet? The sun track at winter solstice will never shade the array.

As for the price I paid, most likely the price on the MT Solar mount has declined, I purchased at a time when steel was moving up fast and steel prices have come down since.

 

[Warpspeed]

Motorized tracker is a lot of trouble, and just not worth it. A much more practical way to get more, is to just add additional panels.
In early days, the very first solar panels were incredibly expensive, and some kind of tracker well worth doing.
Today, panels have become so cheap, its no longer worth building a mechanical tracker.
Easier just to throw up twice or three times as many fixed panels and enjoy all the power.

For most of us, seasonal adjustment of tilt will not make the large difference you might be expecting. It depends on your latitude.
So opinions on that topic from different people can vary quite a lot.

It really finally comes down to the east/west transit of the sun. You then decide what time of day would be most useful to receive the inevitable power peak, and fix your panels in that orientation.

In a cold climate, east facing panels may probably be best, because early morning is when your battery will be at its lowest, and likely the greatest electrical load around breakfast time.
In a hotter climate, there will obviously be more solar anyway, but the biggest load of all might be air conditioning, so you want plenty of power in the afternoon and early evening.

In a temperate climate (where I am) I have half my panels facing east, and half west. I get pretty constant power from sunrise to sunset without anything needing to move.
Early in the morning only half the panels are working, but they are going flat out. Around mid day, all the panels are working, but only at about half rated power. Late in the day the west panels are going really strong. So all day there is almost constant solar power available, perfect for normal expected house loads, where the night time battery might be rather small.

If you have a really large expensive battery, with several days worth of kWh storage, best solution would probably be to face all of your panels to receive just the mid day peak. The battery needs to be large enough to be able to fully absorb all that charging power in a short time.

No single correct answer, it really depends on where you are, and your particular needs.

 

[solvej]

We're off grid and have fixed tilt panels. I would like them to have adjustable tilt. There are a few reasons for this. I'll name them in the order I've realized the needs:
1) Wind gusts. We live far north. In order to get the most gain out of the winter sun, our panels are nearly vertical. Roof mounted vertical panels catches a lot of wind forces. We need them on the roof to avoid shades. 60kg / m2 at wind speed of 58 knots (the highest gust measured here in the past 2 years). Being able to tilt them to horizontal will make me feel safer on windy days.

2) (Near) vertical panels does not catch any sun before 7am or after 5pm. During rainy summer days the sky tends to be blue either before 8am or after 4pm. On such days horizontal panels would be able to charge some during these days. We have a lot of them, hence I'd like the panels to be horizontal during summer. However, we do have quite a bit of snow. When snow starts I'd like the panels to be vertical so the snow doesn't collect (a lot of weight and a lot of work (time consuming handling of safety harness with frozen ropes and with thick gloves) to clear snow off roof mounted panels.)

3) Cloudy days indirect sunlight catchment. We've now had 8 weeks without any sight of the sun. It's not realistic to scale a battery for this. We need to find a way to catch the little solar radiation we can get. I've tested with a panel at 11.53am (the time the sun should be exactly south at our location). When facing directly towards the sun (where it should be according to compass and solar angle calculators) I got Voc of 0.516V/cell. When laying the panel down this gradually increased to 0.549V/cell when it was horizontal. This should indicate that the charging during cloudy November days would be better when panels are horizontal. Our hybrid inverter chargers needs 0.583V/cell in order to start actual charging. (With less voltage the charger consumes more power than solar provides.) But with a more light weight controller there is a chance the horizontal panels would actually charge our battery on these cloudy days.

My conclusion is that I would like to have my panels horizontally mounted (slightly tilted for dust to be washed off by rain) during summer and through the cloudy and windy fall season. Then, when first snow falls, I'll tilt them to vertical. Then back to horizontal some time during the spring.

 

[acdoctor]

Which racking system do you use, and would you recommend it?

I have a DIY rack that looks very similar to this one. I spend maybe an hour a year adjusting panels. Another hour cleaning them after the pollen in the spring. https://sinclair-designs.com/Sky-Rack-2.0-Ground-Solar-Mount

 

[Llaves]

Where was the sun in the sky when you made these measurements? If the new 52° angle points directly at the sun, then 45° is off by only 7°, and the difference in the direct insolation component is only 1 - cos(7°), or less than 1%. The indirect and reflected components are much smaller and won't account for the difference.

 

[acdoctor]

Where was the sun in the sky when you made these measurements? If the new 52° angle points directly at the sun, then 45° is off by only 7°, and the difference in the direct insolation component is only 1 - cos(7°), or less than 1%. The indirect and reflected components are much smaller and won't account for the difference.

The 4 pictures were on December 19th 2021. The 5200 watts was at 10:53 AM central daylight savings time. The 4800 watts was shorty after at 11:03 with the same sky by observation. The sky had been about the same clarity for a couple of hours. By the panel specs I have 6100 watts. 35.5 kw is the best daily total I have seen.

 

[Llaves]

The 4 pictures were on December 19th 2021. The 5200 watts was at 10:53 AM central daylight savings time. The 4800 watts was shorty after at 11:03 with the same sky by observation. The sky had been about the same clarity for a couple of hours. By the panel specs I have 6100 watts. 35.5 kw is the best daily total I have seen.

Why did the power drop as you increased the tilt, which should have better aligned the panels to the sun elevation?

 

[Llaves]

Returning to the underlying question of how much do you gain from manually adjusting panel tilt during the year, I used the PVWatts calculator to model a 4kW array in Little Rock (a nod to acdoctor's location in central Arkansas). I ran calcs for every 10° of tilt from 10° to 80°. The table below shows the results, plus the result from picking the best tilt for each month.

Month/Tilt	10​	20​	30​	40​	50​	60​	70​	80​		Best​
Jan	307.2521​	350.8542​	382.6911​	402.8853​	411.5229​	410.0979​	399.9741​	388.0406​		411.5229​
Feb	344.2616​	379.6576​	403.4417​	415.8009​	417.3043​	408.5679​	390.6158​	371.7366​		417.3043​
Mar	415.4078​	432.8061​	438.004​	431.8854​	415.4157​	389.1399​	354.6141​	322.2954​		438.004​
Apr	486.9364​	488.1921​	476.2554​	452.2101​	417.2234​	372.3698​	319.9746​	270.6518​		488.1921​
May	564.8798​	551.6166​	523.996​	483.104​	430.5144​	368.8619​	299.5532​	234.1706​		564.8798​
Jun	588.6985​	568.4178​	533.9263​	486.1931​	427.32​	359.531​	284.1232​	214.4917​		588.6985​
Jul	578.4541​	561.3645​	529.924​	485.3984​	429.7721​	364.2023​	291.5915​	223.3865​		578.4541​
Aug	546.804​	546.6889​	531.9196​	503.5787​	462.8525​	410.9792​	350.0956​	291.8068​		546.804​
Sep	491.9275​	509.4349​	512.8255​	502.8318​	480.2919​	445.9829​	401.4781​	357.9695​		512.8255​
Oct	405.6234​	438.9012​	459.0932​	466.8611​	462.7056​	447.127​	421.3404​	394.2888​		466.8611​
Nov	343.5786​	392.1157​	427.2893​	449.3722​	459.3982​	457.7249​	445.6764​	431.1751​		459.3982​
Dec	262.8716​	305.85​	338.2364​	359.1203​	369.391​	370.7296​	364.1552​	356.6131​		370.7296​
Total	5336.695​	5525.9​	5557.603​	5439.241​	5183.712​	4805.314​	4323.192​	3856.627​		5843.674​

Picking the optimal tilt for each month results in a hair over 5% gain over the course of the year. This would require 8 adjustments during the year. If you allow only 4 adjustments per year this drops a bit to 4.7%.

So, is it worth it? That's up to each individual. If it's a straight economic analysis and you're grid-tied you just balance the extra production against the cost of an adjustable mount. If you're offgrid, the increased winter production may be the decider (or the extra summer production if you live in area requiring air conditioning).

 

[acdoctor]

Why did the power drop as you increased the tilt, which should have better aligned the panels to the sun elevation?

It increased with greater tilt.

 

[Llaves]

It increased with greater tilt.

Now I'm confused. You wrote

The 5200 watts was at 10:53 AM central daylight savings time. The 4800 watts was shorty after at 11:03 with the same sky by observation.

which suggests that the output dropped after you changed the tilt. Did you decrease the tilt, or is this just a typo?