Does the tilt of the panels really make a difference?

Ozonkiller · October 2014

My panels are on a 4:12 pitch (about 18 degrees) and face due south. In Phoenix the median angle of the sun is 56 degrees altitude. Would it be worth it to adjust the panels with more tilt? The system is a 5.7 Kw with polycristaline (sp) panels. Today at 12:15, I saw a peak output of 4.3 Kw or about 75%.

This is the problem with installing a monitoring system:roll: Some times too much information is a bad thing

Cariboocoot · October 2014

Re: Does the tilt of the panels really make a difference?

Welcome to the forum.

Panel angle does make a difference. How much difference depends on how far off from "best angle" you are, and the best angle may not always be what you think.

How's that for a convoluted answer?

Have a look at this and you may be better able to determine whether a change in pitch will be beneficial for you: http://www.solarpaneltilt.com/

At your location some of your output lost will be due to temperature.

Ozonkiller · October 2014

Re: Does the tilt of the panels really make a difference?

Perrrfect. I really appreciate the info. Based on the link that you provided, the optimum fixed angle would be about 27 deg. 9 degrees doesn't seem to be worth the effort. If I do decide to make a change, it would be to a tracking system. That would mean relocating to my yard. Hmmm, maybe I'll just add a couple more panels.

Thanks for the, no B.S. answer.

I've enjoyed nooping around your forum. It seems like there are a lot of knowledgable and friendly folks on here.

Again,

Thanks

SolarPowered · October 2014

Re: Does the tilt of the panels really make a difference?

Having the panel face directly into the sun actually increases the panel temperature. Most panels today are covered with AR coating, so slightly augmenting the angle so its not perfect, may be better.
Running tests with a pyronometer on a 2 axis tracker, the best tilt to the sun, the panels actually increases in temperature.

Perfect tilt works best in the winter, not on a hot summer.

I would be more concerned with soiling. You live in phoenix. New Mexico, LasVegas, Phoenix, all have high soiling factors. The average soiling factor in the California bay area, is 5% every 3 months, I recommend that my clients clean their panels a minimum of atleast every 3 months of the year, and make sure they are cleaned 1 week before winter solstice, and 1 week before summer solstice, because then I can fine tune the depreciation calculation each year, even though enphase/envoy/enlighten is suppose to take care of that for me.

So were I typically see soiling at 5% every 3 months for my region you typically see soiling at 8% every 3 months.

As of now though your system is on PAR

SolarPowered · October 2014

Re: Does the tilt of the panels really make a difference?

Also for this time of year your production isn't that bad.

These graph's are from a fresh 5.86kWh system I just installed in Oakley CA.
3.61 kWh was the peak for Oct 11.

You also have to realize its not about a peak power any more, its more about harvest, if this system averaged 3kWh for 3.5 hours of PV watts it did pretty good.

This system is also mono crystalline, you are using poly. Poly will tend to see really high peaks in power at peak sun for PTC, but also fall short of power at sunrise and sun fall PTC. So its important when you monitor to review "all the information" not just peak power. The reason why I will always hands down use mono, surface area, and a crazy fast ramp up in power, in less than 1.5 hours the system is already producing 2kWh in early morning sunrise.
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Organic Farmer · October 2014

Re: Does the tilt of the panels really make a difference?

My array is built to allow adjust tilt four times a year. Once my system is completed, I would like to measure the output to verify what difference it makes.

Rick Rowlands · October 2014

Re: Does the tilt of the panels really make a difference?

When I installed my panels recently I was having trouble verifying their angle, but I found an app for my smartphone that will tell you the angle of inline of your phone. Just lay the phone against the panel and it tells the exact degree of angle.

Ozonkiller · October 2014

Re: Does the tilt of the panels really make a difference?

I think things are working OK. 2nd hour after sunrise saw 1.93 Kwh production and the noon time hour saw 4.47 Kwh production. Total production today was 28.9 Kwh.

I just installed a TED 5000 just to monitor my Solar output. My September output was down by about 180 Kwh. A couple of weeks ago I happend tp be walking by my Sunny Boy when the fault light came on. In trouble shooting the system I found the line voltage was climbing to 264V which is the trip point of the inverter. A phone call to the local power company, APS, and the problem was resolved. At least now I can keep track of any problems much better on a day to day basis.

Thanks again for all of your input,

Tom

Cariboocoot · October 2014

Re: Does the tilt of the panels really make a difference?

Organic Farmer wrote: »

My array is built to allow adjust tilt four times a year. Once my system is completed, I would like to measure the output to verify what difference it makes.

You can do this relatively simply by adjusting the angle to a different time of year's pitch while watching the power output. For best results loads should be high when you do this to relate to maximum power potential.

To verify a difference in daily Watt hours you could change angle from one day to the next if you can have consistent loads (or separate measurement thereof so the data can be compared on a percentage basis).

SolarPowered · October 2014

Re: Does the tilt of the panels really make a difference?

Ozonkiller wrote: »

I think things are working OK. 2nd hour after sunrise saw 1.93 Kwh production and the noon time hour saw 4.47 Kwh production. Total production today was 28.9 Kwh.

Tom

Compared to the micro inverter system here in Oakley and comparing insolation, your system is right on point where it should be using poly and amperage ramp up.

Distance from Oakley, CA to equator 4230 km = 2628 miles
Distance from Phoenix, Arizona to equator 3723 km = 2314 miles

2628
-2314
_____

314 miles =longer distance to Oakley

Phoenix Arizona Elevation=1117' above sea Level
Oakley California Elevation= 20'Above Sea Level

Phoenix system do to insolation factors should be averaging a peak 1kWh greater than the system in Oakley CA.

So Yeah you are on par with where you need to be plus or minus some cloud cover

Ks Solar · October 2014

Re: Does the tilt of the panels really make a difference?

I am at approx. at 37 deg. lat. in so. central Ks. My garage roof where my panel is mounted is approx. 25 deg.
Looks like I need about 55 deg. winter. My little system just went together in Jan. I have no monitoring setup.

So far my my led lighting is running dusk to dawn with no lv-disconnects . I just recently added a switch to turn off about 5w worth of lighting for the winter.

Without giving any more boring stats on my meager system

Would it be worth it to remount my panel at 55 deg. or something in between. I would really like to keep it fixed. My balance on ladders and roofs not what it use to be. The only other option would a pole mount .

I realize I need to start tracking stats. Any opinions are greatly appreciated by a total solar newbie.

BB. · October 2014

Re: Does the tilt of the panels really make a difference?

If you are doing lighting for security--Look at installing motion controlled lighting.

Personally, I believe that motion control lighting is better than always on for security.

As to tilt angles and such... Start plugging in tilt into PV Watts or equivalent programs and see what pops out.

Winter is a difficult time for solar... Yes, tilt can give you more energy--But if low hours of sun is the results of clouds/bad weather--Changing tilt will really not do much.

"Station Identification"
"City:","Wichita"
"Array Type: Fixed Tilt"
"Array Tilt:"," 37.7"
"Results"
"Month", "Solar Radiation (kWh/m^2/day)", "AC Energy (kWh)", "Energy Value ($)"
1, 4.30, 425, 32.73
2, 4.88, 427, 32.88
3, 5.25, 484, 37.27
4, 5.80, 509, 39.19
5, 5.75, 507, 39.04
6, 6.01, 495, 38.12
7, 6.27, 520, 40.04
8, 6.33, 532, 40.96
9, 5.63, 470, 36.19
10, 5.36, 480, 36.96
11, 4.32, 393, 30.26
12, 3.68, 359, 27.64
"Year", 5.30, 5603, 431.43

"Station Identification"
"City:","Wichita"
"Array Type: Fixed Tilt"
"Array Tilt:"," 20.0"

"Results"
"Month", "Solar Radiation (kWh/m^2/day)", "AC Energy (kWh)", "Energy Value ($)"
1, 3.62, 357, 27.49
2, 4.35, 379, 29.18
3, 5.03, 465, 35.80
4, 5.91, 520, 40.04
5, 6.17, 544, 41.89
6, 6.61, 545, 41.97
7, 6.82, 565, 43.51
8, 6.58, 553, 42.58
9, 5.49, 459, 35.34
10, 4.86, 436, 33.57
11, 3.72, 336, 25.87
12, 3.08, 298, 22.95
"Year", 5.19, 5456, 420.11

"Station Identification"
"City:","Wichita"
"Array Type: Fixed Tilt"
"Array Tilt:"," 53.0"

"Results"
"Month", "Solar Radiation (kWh/m^2/day)", "AC Energy (kWh)", "Energy Value ($)"
1, 4.61, 455, 35.04
2, 5.03, 441, 33.96
3, 5.12, 472, 36.34
4, 5.36, 469, 36.11
5, 5.09, 445, 34.27
6, 5.19, 422, 32.49
7, 5.46, 447, 34.42
8, 5.74, 479, 36.88
9, 5.40, 450, 34.65
10, 5.44, 488, 37.58
11, 4.57, 416, 32.03
12, 3.96, 386, 29.72
"Year", 5.08, 5370, 413.49

Leave at optimum tilt (~37 degrees) and add 10-20% more panels and don't worry?

-Bill

Ks Solar · October 2014

Re: Does the tilt of the panels really make a difference?

Perfect.. Thank You Bill. We must think alike..

I thought about splitting the difference. PV Watts proves that. Thanks for the link btw.

Also my lighting is just mostly for the traffic areas but motion lighting is next on my list as well.

Do the motion switches like this use any idle power? http://www.ebay.com/itm/LED-Lighting-Motion-Detector-1-10-minute-off-time-delay-12-Volt-LED-Lighting-/121123448124?pt=US_Stage_Lighting_Controllers_Dimmers&hash=item1c3385253c Plus I would need one somewhat moisture proof. Sorry don't want to hijack this.. Sorry

Cariboocoot · October 2014

Re: Does the tilt of the panels really make a difference?

Ks Solar wrote: »

Perfect.. Thank You Bill. We must think alike.. I thought about splitting the difference. PV Watts proves that. Thanks for the link btw.

Also my lighting is just mostly for the traffic areas but motion lighting is next on my list as well.

Do the motion switches like this use any idle power? http://www.ebay.com/itm/LED-Lighting-Motion-Detector-1-10-minute-off-time-delay-12-Volt-LED-Lighting-/121123448124?pt=US_Stage_Lighting_Controllers_Dimmers&hash=item1c3385253c Plus I would need one somewhat moisture proof. Sorry don't want to hijack this.. Sorry

Any active circuit will use some amount of power. While it is waiting to detect motion it is active.

BB. · October 2014

Re: Does the tilt of the panels really make a difference?

Motion detectors seem to take about 0.1-0.2 watts typically (at least the DC versions). You will just have to search for something that meets your needs:

http://www.amazon.com/Motion-Sensor-Automatic-Switch-Infrared/dp/B00E1C55CQ (12 volt)
Do it yourself kits/products (mostly DC)
Infrared Motion Sensor - 12 volt 8 amp (expensive, draws ~1 watt when off, large current switch)

In California, we now need motion detector lights for our bathrooms (the state feels that its citizens are no longer capable of turning on/off light switches based on needs anymore

--where is the "barfy" emoticon when you really need one). Lots of versions from the megamart hardware stores:

http://www.homedepot.com/s/motion%2520detector?NCNI-5

-Bill

bmet · October 2014

Re: Does the tilt of the panels really make a difference?

As a curiousity I purchased battery-power motion detecting lights for use around the home. I find that they really cut down the number of 'flicks' after dark. Once we got used to them, we don't even look for the lightswitch anymore. Now we just replace batteries once in a great while. I haven't tried to figure the cost of batteries vs. amount of time the light stays on accidentaly, but I have noticed a $4 reduction in the monthly utility bill. The AA used in the hockey-puck lights get replaced about every 3 months, so I think the savings depends on how many tenants there are

Ks Solar · October 2014

Re: Does the tilt of the panels really make a difference?

Wow, good find on the Meco sensor. The Home Depot or Lowes units use a lot more power while doing nothing

I did not see it in the specs but in the reviews said 15 mA .. Big difference from .20 W and 1 W - I ordered one so we will see.

Does the tilt of the panels really make a difference?

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