Panel tilt
- Thread starter pda1
- Start date
About 40 degrees would be ideal year round, but usually you would lean towards better production in the summer when there is more daylight hours, so something around 30 degrees?
Consider this:
unboundsolar.com
Consider this:
Tilt & Azimuth Angle: Finding the Optimal Angle to Mount Your Solar Panels
Learn how to find the optimal tilt and azimuth angle to get the most production from your solar panels.
unboundsolar.com
That’s only true for grid tied installations when optimizing for maximum annual power production. If this is an off grid application, it should be optimized for the worst stretch of cloudy winter days.About 40 degrees would be ideal year round, but usually you would lean towards better production in the summer when there is more daylight hours, so something around 30 degrees?
Consider this:
Tilt & Azimuth Angle: Finding the Optimal Angle to Mount Your Solar Panels
Learn how to find the optimal tilt and azimuth angle to get the most production from your solar panels.
So if I'm at North 40° then I should tilt my panels to 40° up from the horizontal?About 40 degrees would be ideal year round, but usually you would lean towards better production in the summer when there is more daylight hours, so something around 30 degrees?
Consider this:
Tilt & Azimuth Angle: Finding the Optimal Angle to Mount Your Solar Panels
Learn how to find the optimal tilt and azimuth angle to get the most production from your solar panels.
chrisski
Solar Boondocker
- Joined
- Aug 14, 2020
- Messages
- 5,570
Look at the calculator in my signature block and play with some numbers And see what the best tilt is.
Not counting AC, my power production is by far the most on winter nights because of the propane heater blowing and the electric it uses. So, I may tilt higher for that December shortest day of the year. If I do get my AC working on solar, panels will be flatter because I use the AC in the summer months. AC takes so much more than everything else, I would not worry about winter production because there’s be so many panels that in the reduced need in the winter months, any angle would work.
Kind of comes down to an energy audit based off low production verse high production to include at different times of year.
Not counting AC, my power production is by far the most on winter nights because of the propane heater blowing and the electric it uses. So, I may tilt higher for that December shortest day of the year. If I do get my AC working on solar, panels will be flatter because I use the AC in the summer months. AC takes so much more than everything else, I would not worry about winter production because there’s be so many panels that in the reduced need in the winter months, any angle would work.
Kind of comes down to an energy audit based off low production verse high production to include at different times of year.
pollenface
Solar Addict
I use an android app called "optimal tilt for pv systems"
It gives daily/monthly/all-year tilt recommendations based on your location.
It gives daily/monthly/all-year tilt recommendations based on your location.
Great calculator but I'm confused about the Installed peak PV power [Wp] *
I read the explanation but it's beyond me...
Horsefly
Solar Wizard
Here's a site that has been around for quite a while. I think it is a little to nerdy, and probably overkill for trying to figure out the tilt, but it is hard to argue with the logic: https://www.solarpaneltilt.com/
My place is at about 38°N latitude, and we pretty much only use it in the Summer. We went for about a 40° angle, and it has been fine.
My place is at about 38°N latitude, and we pretty much only use it in the Summer. We went for about a 40° angle, and it has been fine.
Now I'm progressively getting confused.
Tried some android apps which were just nag-advertisement types. They do give you an angle but there's a discrepancy in results between what fixed angle is best in Northern latitudes.
So....I still have no solid answer.
At North 40° at the Summer solstice the Sun's declination at LAN (Local Apprent Noon) is North 23° 26.2' and the corresponding angle of the Sun above the horizon is 73°. So, simply, the panels should be tilted to 73°. This would only be true for the Summer Solstice. At the Winter Solstice the Sun's angle would be 27°.
Tried some android apps which were just nag-advertisement types. They do give you an angle but there's a discrepancy in results between what fixed angle is best in Northern latitudes.
So....I still have no solid answer.
At North 40° at the Summer solstice the Sun's declination at LAN (Local Apprent Noon) is North 23° 26.2' and the corresponding angle of the Sun above the horizon is 73°. So, simply, the panels should be tilted to 73°. This would only be true for the Summer Solstice. At the Winter Solstice the Sun's angle would be 27°.
Well, according that guy it's something like 38° x .76 + 3.1° = 32°
This is probably being "over-thought" by me.
wattmatters
Solar Wizard
It depends on what you are trying to achieve and the sort of system you have.
Optimal for what exactly?
There is a panel orientation which, provided there is no barrier to loads, will provide the highest annual output. That fine for grid tied sets ups with good feed in tariffs. But off-grid it may well be sub-optimal as it's more important to have power when you need it.
Without knowing what your needs are and the sort of system you have or propose then the answer is "it depends".
It may be more important to sacrifice overall production total to have better output in the Winter. Or to have a more even spread of production across the day. Or be able to recharge batteries earlier in the day, or cover aircon use in the late afternoon. Perhaps your location experiences morning fogs a lot at times of year you really need to extract the most, and it's better to face panels a bit more West rather than waste the end of the day with clear sky. etc etc
A very good point concerning the usual better part of the day for weather- more westerly orientation.
Edited- I'm thinking making a ground mounted tilting array- not a pole mounted system.
Here's the simplest site so far- Solar Panel Tilt
Here's the simplest site so far- Solar Panel Tilt
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GrumpyOldRetiree
New Member
- Joined
- Jun 12, 2020
- Messages
- 24
Here is the calculator I use. (caveat: I'm a simpleton):
www.solarelectricityhandbook.com
Solar Angle Calculator
The solar angle calculator tells you by location the optimum angle to get the best out of your system.
www.solarelectricityhandbook.com
svetz
Works in theory! Practice? That's something else
It really depends.
For example, I live in Florida and use almost no power in winter and a ton of power in summer. So, set the tilt for summer right?
Nope. Summer is also when we get a lot of rain.
But I live in Florida which has a great net-metering agreement. So, I should optimize for year round, right?
Well no, turns out what was most important to me was wind pressure on the roof (hurricanes <sigh>). So, I minimized those forces by having them flat on the roof.
But, I'd recommend SAM. It'll take into account where you live, your typical weather patterns, you can input your power consumption my month, add in any shade trees, and then you can play with the tilt to see what gives you the best for you. It's a beast, so watch the video tutorials if you go that way.
For example, I live in Florida and use almost no power in winter and a ton of power in summer. So, set the tilt for summer right?
Nope. Summer is also when we get a lot of rain.
But I live in Florida which has a great net-metering agreement. So, I should optimize for year round, right?
Well no, turns out what was most important to me was wind pressure on the roof (hurricanes <sigh>). So, I minimized those forces by having them flat on the roof.
But, I'd recommend SAM. It'll take into account where you live, your typical weather patterns, you can input your power consumption my month, add in any shade trees, and then you can play with the tilt to see what gives you the best for you. It's a beast, so watch the video tutorials if you go that way.
Hedges
I See Electromagnetic Fields!
- Joined
- Mar 28, 2020
- Messages
- 21,785
For that, multiple orientations.
A single orientation will have a curve of production that falls off when sun is at an angle.
Two PV arrays oriented at 10:00 AM and 4:00 PM will present 0.7x as much area toward the sun but have a more broad curve, flatter on top. It can deliver 1.4x as many kWh/day for a given peak power. These arrays could have separate SCC (or MPPT input), but can be paralleled into a single one for better utilization of the electronics.
Delivering more power early and late in the day means battery kept fully charged longer, starts recharging sooner. Smaller battery is sufficient to get through the night.
PV panels are cheaper than batteries, so good to over-panel and buy less battery. But limit max charge current to what battery can handle.
It dosent really matter to much , today at 900am I’m getting 2800 watts my full power noon is 3700watts
at 10am I was getting 3200watts and absorb is lowering the charge rate ?
I’m at 42o at this time of year the panel are lined up ?
in the winter I get about 2200watts on a good day at noon so about half .
Mid Summer time I get lots of power .
Things start dropping off now .
at 10am I was getting 3200watts and absorb is lowering the charge rate ?
I’m at 42o at this time of year the panel are lined up ?
in the winter I get about 2200watts on a good day at noon so about half .
Mid Summer time I get lots of power .
Things start dropping off now .
This was my goal to use 4 panels, 2s2p with each group pointed ~ 35 degrees from noon winter sun angle. I will have just one MPPT charge controller @145Vmax using the LV2424 MSD 2.4KW . Planning to use Talesun 330w panels with 40VOC max which I am ready to click the buy now button on. Starting with 24v @ 100AH LiPo ( 2x12) and hope to add another in parallel soon.
The panels will be about 25 feet away from the batteries in a heated box. What guage wire would you recommend for two panels at 80VOC for that distance?
Do I need a combiner for the two groups of panels or is the one not affected by the other when not getting sun?
To summarize:
-Depends on what you are going to need power for. (winter vs. summer things). Optimize for that season.
I use the NREL PV watts calculator. SImple, flexible and NOBODY WILL CALL TO SELL YOU STUFF. My latitude is 40 (Philly).Rule of Thumb would dictate a 40 degree angle year round but 25 was most pracitcal for me. Interesting that Zero and 25 degrees gives me about the same kwatt-hrs in the summer time. From the attached comparisons it does not appear to make much sense for me to bother with tilt ups during the summer.
-Depends on what you are going to need power for. (winter vs. summer things). Optimize for that season.
I use the NREL PV watts calculator. SImple, flexible and NOBODY WILL CALL TO SELL YOU STUFF. My latitude is 40 (Philly).Rule of Thumb would dictate a 40 degree angle year round but 25 was most pracitcal for me. Interesting that Zero and 25 degrees gives me about the same kwatt-hrs in the summer time. From the attached comparisons it does not appear to make much sense for me to bother with tilt ups during the summer.
Looks like your system losses are different between the two reports.
Richard Lee
New Member
Solar Radiation Monitoring Laboratory Department of Physics
http://solardat.uoregon.edu/SunChartProgram.html this will help you calculate what you need.
I used before I built the adjustable tilt into my semi-fixed array rack.
If you do want to make it adjustable, you might want to add a one foot shadow-stick.
Install the stick in the center of a white 3 or 4 inch disk. You can check it around noon,
and tweak you angle adjuster for max power. From the pdf chart, I found that mid winter
sun is very low, north of Boston. So the angle is steep. But that allows the snow to slide off.
The plot attached is the data for my area. Study it and you'll find a ton of info.
http://solardat.uoregon.edu/SunChartProgram.html this will help you calculate what you need.
I used before I built the adjustable tilt into my semi-fixed array rack.
If you do want to make it adjustable, you might want to add a one foot shadow-stick.
Install the stick in the center of a white 3 or 4 inch disk. You can check it around noon,
and tweak you angle adjuster for max power. From the pdf chart, I found that mid winter
sun is very low, north of Boston. So the angle is steep. But that allows the snow to slide off.
The plot attached is the data for my area. Study it and you'll find a ton of info.
Attachments
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wattmatters
Solar Wizard
One of the advantages of using the NREL PVwatts estimation tool is that the simulated hourly production data accounts not only for your latitude and longitude, array orientations and tile, PV array and inverter characteristics but importantly it also accounts for the weather patterns typical for that location. e.g. seasons where morning fog or afternoon storms might be in play and not accounted for by sun charts.
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