South West vs. South - Get MORE POWER - DIY Solar Panel System Performance - Actual Data
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- Опубликовано: 31 май 2024
- Mid year (equinox) results comparing South, South West, and West facing solar panel performance. Is facing all panels South really the best?
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Timestamps:
00:00 Intro
02:04 Why You Want Clipping
03:17 West Array Winter Result
04:14 South West Array Mid Year Result
07:09 Full Array Output South
07:47 Full Array Output East / West
09:48 Full Array Output South East / South West
10:50 Full Array 3way Comparison
11:35 Why South West Works Better - Solar Declination, Azimuth, Elevation Impacts
16:29 Conclusion
18:01 Energy Pal - Easy Solution for Going Solar! 
Хобби
It seems RUclips ate my comment but I'll type it in again. This is a great video with empirical data. I did some calculations in PVGIS for my location. I'm further north, but the principle should hold. As suggested in the video, making a shallow V pointed south loses very little production compared to having all the panels due south. PVGIS predicts that having each leg of the V 10 degrees from south gives 99.6% of the annual production of the south facing panels while 30 degrees should still give 96.8%. Any angle up to 15 degrees from south (i.e. 150 degrees inside the V) carries less than a 1% penalty while giving a more spread out production during the day since it takes the sun two hours to move from being straight in front of one side to being straight in front of the other. If clipping is taken into account, this would yield more energy over the course of a day than a south facing array. In other words, Dave's findings in the video confirm the theoretical model.
In addition to benefit of more power there are other key advantages to orienting panels in two directions. One advantage is that on days that are cloudy part of the day but at least sunny early or late, you are more likely to still collect significant power sometime during the day. A cloudy midday can pretty much wipe out the performance for a whole day if all panels are pointed directly South. A second advantage is that if you can collect significant power starting a couple hours earlier and a couple hours later, if you need to rely on batteries for the rest of the day you have a significantly shorter window each day when you must rely on batteries, meaning you can get by on a slightly smaller battery bank.
Yes, the weather advantage is more significant than I anticipated. It is often cloudy in the morning or afternoon and sunny the rest of the day. With panels facing multiple directions I get a much more balanced output from day to day.
Also in some countries like the UK, buying power from the utility company is expensive (e.g. 35p/kWh) but they give you almost nothing for feed in (sending power to them is 7p/kWh ). So you may be better off producing less power overall, but for a longer duration, with East, South and West panels. Producing a lot at midday and exporting is poor economics in this case. Of course, if you've got batteries it is all about total output throughout the day.
@@ProjectsWithDave Yeah was wondering if you had panels facing all directions you could get away with less facing the south since they're clipping power anyway, putting more on the sides would give you the more balanced output through out the day? I just got 1 panel and having fun with it, was thinking of a solar dome, but thats just wastes panels that aren in the sun when you cuold just move them around, (although they still capture ambient light). So ive investigated the solar trackers, which are just as expensive as more panels and more maintenance so i dont know if its better. Maybe a simple one, like a wheel that lets you spin the array into just three postitions youve shown here to capture all power curves. Could give you 90% of the benefit of a solar tracker with maybe 1/10th the cost. Anyway nice data, very useful, thanks for sharing.
@@willsmithorg octopus have increased their export to 15p /kWh which is pretty good! Not sure what you have to do to get it.
@@matthewwakeham2206 that is good. I was going to DIY my panel install and forget about the small amount I export. Now maybe a bigger install, worth doing properly.
I think you might have been saying this in the video but if you are trying to extend the time your panels are producing to later or earlier in the day then you may want to adjust the angle of the panels for where the sun will be at that time of day. Whether that will drop your overall output I don't know but obviously if you had panels tracking the sun they wouldn't just move east to west but the tilt of the panel would also change throughout the day.
Always good and usable information from your videos. Thanks Dave!
This is just what I was looking for. I have 8.5kW of panels oriented to SW and since there is never enough of panels, I'm adding another 7.5kW to a roof oriented to SE. It's only 1kW more then inverter handles (15kW) and my grid export is limited to 13.3kW anyway. Thank you for your information, it is highly appreciated.
Great show. Your commitment is impressive. Thanks again.
nice video, exactly the analysis I was looking for. much appreciated!!
So basically the conclusion is solar panel facing South-SouthWest (202.5 degree) and South-SouthEast (157.5 degree) are the best direction.
And if it is grid-tied system, and your utility company charge you extra during peak time (usually 4 to 9 pm). Your best bet is face ALL of your solar panel to South-SouthWest (202.5 degree)
This highlights the reality that every situation is different. That's why I like to do test and give you the results to apply in the most effective way for you.
My maximum requirement is during summer months for air-conditioning.
Great video, Dave! Very interesting just how much thought can go into a solar setup.
I'm not sure this much thought is necessary, but it helps to know the magnitude of the impact of different options.
We're getting solar panels on our house soon and the info from this channel has helped me be a lot more confident in what our system will do for us. A lot of the space on our roof is east-west, and I was worried that that was going to be a problem, but your data helps me believe that it's not that big of a deal after all, and might even have advantages. Thank you!
Thanks! I'm glad it has been helpful for you.
The biggest problem is shading. Even a fractionally small portion of the panels in shade at any time drops output in a big way.
@@Mrdsmith500 yes I found that out with my system. I have two arrays and the winter solstice the bottom of my rear panels get shaded about 4 inches from the front panels. it reduces my output about 12 to 15%. So I’ve tilted the front panels to 30° and the rear panels to 40°. I did have them both at 45° angles until December when the sun was very low to the south.I didn’t realize how huge of a difference a small amount of shading does.
Very useful intel. I'm looking forward to your winter calculations.
Thanks! Meet Too : )
I recently did a DIY upgrade of my main southern-system and have been thinking about remounting the old (20-year-old) panels in a west-facing direction to augment the upgraded southern-facing system. I have a little test system going right now but its only been running for a month... but I am already seeing more or less the same thing that you are reporting. Maximum production of a purely west-facing system occurs a bit too late in the day and sunset comes so quickly it is clear that a lot is being left on the table.
Knowing that I can get something even better facing South-West while still filling out the late afternoon is invaluable information! Thank you so much!
I'm so happy that this data is helping people in real world decisions! Thanks for letting me know!
By far the best solar analysis
10:05 NICE graph for SE + SW! Seems like what I need!
Awesome, glad it was helpful.
Nice work, many thanks
Thank you for sharing all your hard work!
Thanks, my pleasure!
Excellent video, you really put loads of work into this, but a point you missed is by spreading out your panels SE/S/SW is it will make your batteries last 20-30% longer life, in two main ways, You be using power from your panels 2-4 hours longer, and you're be spreading out the recharging times, which drastically increases battery life, especially LB.
Thanks for mentioning that, yes that's true for a system with batteries. At the time I filmed this, I didn't have any batteries connected, so it wasn't at the top of my mind.
@@ProjectsWithDave I
Lot of interacting variables including your latitude. Thanks for the video.
Glad it was helpful!
Interesting experiments. Wish you all the very best fir an early success
Thank you very much!
Love your information. The west facing modules needed more angle. Since the sun is on its way down.
Increasing the angle actually reduces production. The sun is very weak when it is low on the horizon.
Really good information here. So my solar adventure began last year in March. I had a company install a ground mount system with Ironridge parts and SolarEdge inverter. All I could afford for someone to install was 21 panels. They told me I needed 50 to achieve an 85% offset. Next, I expanded my 21 panel array with an additional 29 panels to get to my 50 panel array. All are facing south and I’m able to get up to 13.4 kw at peak. I realized I still had room on my 10k inverter, but I built a second array of 20 panels, but west facing. I noticed that past 7pm in the summer I still had sun on a fence line that faced west while my original 50 panel array was starting to get some shade. Now I can achieve 17.6 kw on a perfect summer day, and rarely see clipping, but it has happened a little. So I built myself a battery house and I plan to add nine SolarEdge batteries. Keep in mind this is a 5 to 10 year project due to the cost. However, I will still need more panels to fill batteries. On a heavy summer days use, I can use 160kwh, but I am only producing at best 125 to 130 kWh. So I need enough panels to take care of real time use and fill batteries for when the sun goes down. I have to replace both my current inverters with energy hub inverters, two 10k and one 11.4k. I can slide in an additional 60 panels if my math is correct and using 345 watt panels. My biggest concern is balancing the project. My limit to export is 21kw. So I have to install battery, fill, and not exceed 21. Add more panels, not exceed 21, then add another battery. My bell curve is very sharp though and I really need to see how I can widen this out. So to recap, 50 panels facing south and 20 panels facing west as of right now. I will add 60 more panels, but I just need to see what direction(s) to face them.
You would probably get the best year-round production by facing them SE. However since you already have so many panels facing south, you may see too high of an input at peak production times to make use of the available power. It would depend on what time of year you need the most power, the size of your batteries, and how much they can accept as a peak input. There is a lot to consider for this analysis.
Thanks Dave, great video again!
Thanks!
Sounds good. I love prizez :)
THIS IS THE BEST INFORMATION. THANK YOU!
Glad it was helpful!
I would suggest bifacial panels with reflectors I think it would be interesting to test that. Or bifacial mounted vertically for optimum angle.
Thanks for the hint !
At 8:08 is exact what I was calculating theoretical a year ago, but as of the wind and fixing conditions on the roof I can do it, I didn't test it.
The main reason for this solution is to maximize the direct usage of Solar energy during we use it and reduce feeding, even still legal.
That also should reduce the load- and de-load of a later used battery pack also.
The loss all over is not that important as I oversize better to be sure also during less bright skies.
I just have to find out the angle, as I can ONLY go west and east and see how much to lift some day.
Last 4 months I had just the minimum bill of 30 kWh as of law here feeding ok, as long I still have bill.
So at moment with 49 Cells (16.5 kW peak) on main 4 Inverter I keep 98% Solar of all used, and keep tracking hints for further settings.
thanks for the excellent analysis. i am a small person experimenting with very feeble resources. this has given my assumption a concrete base.
Glad it was helpful!
Thanks for showing us your experiments! And thanks for mentioning the "mini-rails"! Shipping to here is a killer and these could just go in the mail. (I've been using "Z clips" but they're not a total solution.)
I have Chinese plug-in microinverters that claim to be 700, 1000 or 1400 watts but they never really put out that much. They seem to have a sort of "soft clipping" where the more power going in, the less efficient they are. (And the 700W ones have no cooling fans, so they reduce output even to half to avoid overheating.) So if an inverter has say 3 solar panels, it might make sense to face the panels for each microinverter SE, S and SW or somewhat those directions to maximize daily output. And spread it out. (For 2 panels, maybe SSE and SSW at 30 deg?)
At 53 deg. N. we don't get much output in the cloudy winter with long, long tree shadows. My best panels are at 45 deg, not 53. (others are flat on the roof at 18 deg.) 45 gives 96% at summer solstice but still 86% (of not much) at winter solstice.
I also have batteries and charge controllers making a 36V DC system to run LED lights & essentials (freezer via 36 to 120 V inverter) in what I expect will be hard times with the grid sometimes down ahead. (There are lots of little adjustable DC to DC down converters from China to run 12/24V appliances from 36V.)
Great analysis the real production differences lay in the vertical angle from 18 degrees to 60 degrees depending on your latitude.
Yes, the tilt angle of the panels is critical, but much easier to get data on from online tools.
Thank you for the great video!
Bifacial solar panels would definitely add another great data set in this experiment 🌄👍. Thanks Dave!!!
Don't worry... It's coming.. : )
This is great data!
I got rid of this issue completely with my 2-axes tracking panels. It took several years to perfect, monsoon storms were the biggest headache, and one tornado, but I'm good to go now.
How many panels are on your tracker, and what tracker system are you using?
@@ProjectsWithDave I have a total of 8 arrays, 2 have 4 panels and 6 have 8 panels. A total of 13.5kw. I am using my own tracker I built with a commercial controller. It looks a the length of the day and then does the math to pulse the panels to the west. They start the movement at 10 am and finish at 1600 hrs. 20 minutes after sunset I pulse them back to the east. The east pulse is just over 30 minutes since the linear actuators are rated at 20% duty cycle.
Nice!
HOWdy P-W-E-D-D, ...
Thanks for the Comparison
COOP
the WiSeNhEiMeR from Richmond, INDIANA
...
Nice analysis. Solar rocks!!
Thanks!
I have 24 panels, 12 facing southeast (6 Santan 250w and 6 Renogy 300w) and 12 facing southwest (6 Santan 250w and 6 Renogy 300w). No grid tie, off grid (3000 KVA 48V Victron Quattro) with 10 kwh of Battleborn LiFePO4 batteries to get me through the night. My small house runs on less than 1000 watts per hour so I wanted to capture the sun as soon as it rises and catch it to it sets to keep batteries at 100%. If I was grid tie, I would face them ALL south to maximize output back to the grid. Grid is backup for my system. I like how methodical and exacting you are in your testing and analysis. Very interesting, Keep it up...
Thanks! Sounds like you have thought out your system carefully. As you said, grid-tie vs off-grid can be a significant factor in panel orientation.
Love the K2 mini rails mounted with the roof mount pad has the soft tar like seal ran the screws in with 3" framing screws had torx head. We been through two seasons of heavy monsoon weather here in AZ not one drop of leaking. I started out wanting to just power a light with one 12V battery now I'm running a small AC unit with a 60-amp 12V charge controller. I found with the 100-amp lithium battery not big enough to power the small AC unit in high summer heat. Now I'm looking at EG4 3kw system might upgrade to 8 panels. I'm only 45 min drive from Santan solar that's the smaller cost of the project batteries and controller where the money is. This was more like an experiment to learn off-grid solar wife and I looking to buy some land in NE AZ I will have to build a larger system.
That's the thing with solar... once you start you just can't stop!
Hi Dave, thanks for your comprehensive review! A variable that you did not take in to consideration is temperature. Assuming a person wants the most output on a YEARLY basis, you need to consider temperature as well as direction. Your panels that clip n April will not clip as much or perhaps not at all in the summer when temperatures are higher and voltage is decreased. Similarly, the panels that face SSW will be hotter in the summer afternoon sun when you expect a bump from their direction, hence the voltage will be lower and less power. Your numbers look good in April when you have cooler spring temperatures, but I don't think, on a yearly basis, the results will be as clear. I operated 3 arrays in the mountains in California and faced different directions for all 3. Factors that drove those directions were mountains, trees, getting a higher payback from kilowatts sold back in the summer versus winter, etc. I've owned 3 houses with multiple arrays and kept daily logs over the last 20 years .... just my 2 cents.
I have not found heat to be a significant factor in my summer production. My clipping in April and July is very similar. However, it rarely gets over 90 deg F here. It may be a bigger factor in hotter climates.
Hi Dave: I just read an article in PV Magazine that showed Bi-Facial Solar panels only lost 2% of their production in snowy climates due to snow cover compared with Mono-Facial panels. The Bi-Facial panels have two advantages in Snowy climates, one, the reflections from the snow help to melt the snow cover on the front of the panels faster, and two, the Albedo from the snow on the ground increases production by 19%. Overall, the Winter production of the Bi-Facial panels exceeded the Mono panels by 33%.
I don't doubt it. From what I'm seeing so far they outproduce everything else I've tried.
A buddy living off grid in Montana, found an important trick was mounting panels back to back upright, aiming straight east and west. By mounting the panels east and west he got some production first thing in the morning, and some last thing in the evening. By having the panels completely upright, they did not accumulate any snow. This was critical for production when snow was an issue. (and in his case the panels were mounted in a difficult to access area, that was not wise to try to remove snow from) Used panels, are now cheap, so his answer is just to add more panels.
When space isn't an issue, the low price of used panels opens a lot of doors to creative solutions.
That's clever. I found my corn field last year planted E-W shaded a lot of the rows behind the leading edge, this year I'm planting N-S. Plants are the original solar generators and they lead the conclusions.
I have a South-facing roof. Oversized my system 120% of normal usage to factor in growth, degradation, and increased power needs ... I have some clipping but the NEM 2.0 program in California makes my electric utility payment $0 anyway (they pay me each year around $200 due to selling back excess power at agreed tariff rate). That said, long term I would love to expand the system, add an EV and a bi-directional charger and also get some SE-facing panels on my sideyard for some late day production. That said, with our kWH price around $0.30/kWh and 10%-18% YoY increases my system gives me a $467k+ ROI using your calculator due to how expensive our electricity is and the 10%+ increases that don't seem to be slowing down due to a lack of interest in growing our power production in the state. More than financial reasons, once I have batteries (or can use my EV battery via bi-directional charger) I want to increase resiliency in my state that often sees fires, rare earthquakes, and repeating power mismanagement.
Nice! High power rates are unfortunate, but they do make it easy to justify solar. : )
Supurb analysis!
interesting, thanks, also for the link to the website with the calculators. Please, energy, not power
Nice analysis. I have Solar panels on my RV and once I realized that an East/West array produces almost as much power as a South facing array, I never bothered trying to face the panels "into the Sun", you get what you get.
If you want to drive yourself crazy... I read recently that a Utility Scale Solar Farm is going to be installing the panels parallel to the ground (yes Flat mounted panels). Their reasoning is that with the combination of reduced panel cost, savings on racking cost and being able to increase panel density (due to reduced shadows from adjacent panels) they can generate more Energy from the same amount of land as a tilted or tracking Solar installation. They are however, investing in panel cleaning robots to keep the panels operating efficiently.
With this said, is your next project going to be flat mounted panels? The Gauntlet has been laid at your feet...
Very interesting! Thanks for sharing that. I imagine that was done close to the equator in a location with no snow. I have some test panels set at a very low angle, they tend to collect dust much quicker. Maybe that makes sense at a utility scale installation with dedicated cleaning bots, but I don't think that's practical for the average homeowner. Also, I'm pretty far North of the equator so the sun is low on the horizon in the winter. When I was in Alaska last, I saw a building with the whole side clad in solar panels, perfectly vertical orientation. I think the takeaway is not to think "traditionally" about solar installations. Everyone has a unique set of circumstances to consider. Think outside the box... Thanks!
@@ProjectsWithDave i like you mention vertical here, off-grid folks struggle most with winter output still they angle their panels to the summer optimum.
Nice job with this analysis, in offgrid systems at least ussually the inverter sizes are not that many to chose so clipping is an issue normally, in my system is the battery charger the bottleneck. I think that analysis of clowdy day would be intresting
Bifacial panels change the options quite a bit as you can see in this video: ruclips.net/video/1SXNjsSsmq0/видео.html
Also my panel are way more efficient during the winter. I don’t have consistent data , but the few data points show even though we have less sunlight we have more efficiency. We are in Florida. Our biggest disadvantage is the constant cloud cover.
Temperature can have a significant impact on panel performance. If you have a lot of cloud cover, you would benefit from bifacial panels. They really shine relative to standard panels in cloudy environments. Here are some options on my website: projectswithdave.com/solar-panels/
This was really helpful. I have a existing array on a 40x60 shop that is 8k watts and produces a max of about 6500 watts peak. I get 30-35kwh in the winter and 55-60kwh per day in the peak of the summer in Northern California. There is zero shading. This exceeded my expectations. Living what is the beaurocratic hellhole of CA we have seen our true-up bills go from $1200 per year to now $3000 per year. This year we added an EV to save $500 a month in gas as we have a 34 mile round trip commute to pickup/dropoff kids. This adds up. I fully expect the true-up bill go up another $120 per month, now $4300 per year true-up. Thus with the 30% tax incentives I am going to do 60kwh of battery using eg4 LL and charge the car ($12k after taxes), have backup power and start peak-shaving the usage as I have a pair of sunny islands. Peak rates are up to .52c per KWH here now, so I am thinking about removing my 8000 watt existing 14% efficient panels and putting in some 550 watt bi-facial panels for $8000 that are 21% efficient. I already have another inverter that will take in 7500 watts max and the building faces perfectly south (sb6000us). I learned from doing some research that I could either remove all the panels on the roof and go up to 16,000 watts using the same wiring that is in place, not having to replace the racking, and sell the older panels, or add a single row of the 550 bifacials to the north side of my building but use some rack extensions to get more like a 2:12 pitch. There is one spare 10 gauge wire set on the roof which can be used w/ the bifacials to do about 6600 watts in the add-on scenario. Either way, I anticipate $1.00 per KWH will be here within 8 years based on how things have gone the last 7 years since owning solar. It's a waste of time pretty much to try and fill in those edge gaps of a few hours on E/W, just face everything south and up-size the system- with battery storage on top of this I can almost flip the breaker on the main and do everything except run a 5 ton AC and a 5HP well pump.
Wow, $0.52/kWh!! With those prices I guess its not hard to justify a significant upgrade to your system. Keep in mind, if you face everything south you will need inverters and chargers that can utilize that peak input to take full advantage of it. In general though, I'm not a fan of East or West facing panels, they don't perform well in the winter.
@@ProjectsWithDave It's a no brainer at this point to add at least another 8k watts(16k total) - the panels are only .48c per watt for bifacials in a pallet, so $3800 or so in panels to double the system output. Winter production should be 40-60kwh per day and summer production around 100kwh per day. With six children under our roof, this is a no-brainer. I would imagine with this size of system I can run a more specialized mini-splits all day long and even off of battery at night until I get down to 20% on the LiPo4 bank (e.g. use about 45kwh after it's dark). It's really a great investment for the future - I can't think of anything that is more inflation proof as the cost of living is always increasing.
i enjoy hearing about your findings with the emphasis on efficiency. I wonder how what would be the effect of tracker mounts? I suspect to realize your goal of capturing the most power you will need more than panels and inverters. Movement to follow the sun and storage for the high collection times some to mind. And as always there is the consideration of cost...... Looking forward to your next video and what data you have collected.
Thanks! My goal of optimizing performance vs cost usually rules out tracking systems pretty quickly. Also, I hate maintenance, I see it as a tax on my time and I expect tracking systems would require more maintenance over the long rung than a fixed system.
I need my solar energy earlier in the day especially in winter. And just added some more panels
If time of day solar input is that critical, you might consider a larger battery.
I'm expermenting with 4ea QCells 475 bifacial facing SW at 45deg. Getting 200W with the early morning sun now vs 0 before.
Nice! It doesn't seem to take a whole lot of angle to pick up the morning and evening sun.
I’m adding 6.65kW facing 215 deg azimuth, angled at 66 deg to help with our high evening loads after work. Peak is around 4pm now, 3 pm next week with time change.
Based on your work it looks like a S. East and S. West facing system would be best in an off-grid setup. My system dose not have a clipping problem as I am off grid with a EG4 18K PV.
I wonder if this will be more efficient because of load. A steady load will stop the battery from charging and discharging (and the associated losses) but will just use the extended flat solar O/P
Angle and tilt being two different things.
You need to change the tilt for winter and later sun capture. As in they need to tip up at the top for winter.
Mine are 25o and 75o.
Make senses?
i guess to make it most efficient with what you are currently working with
Excellent topic to make video on,
i'm also looking for solution like this, my mppt supports 40amps at 24volts maximum, I find the cost of mppt charge significant, so cant upgrade, my panels will be outputting 1360watts(bifacial) or 1100 from one side. And so the controller supports 1100watts maximum output.
1. I cant figure out the correct angle spread between both directions plus I'm not sure at what inclination I should put both of them to maximize power output based on my coordinates on earth. I m sure there should be some online calculator which I can not find.
2. Does this also depends on how strings (or panels in my case) are joined? If I connect both of them in series and they in different directions, the current will be reduced in the other panel and hence in series, the output will be of the lower one, and how does this stands based on parellel connections based on how voltage will change in different directions?
I just stumbled on your site and you break things down so that a newbie like myself can understand. One question I have, is there a website that shows which direction your roof faces. I recently had solar installed and what I'm noticing is what they told me were south facing panels produce the least amount of energy. My west facing actually produce to most followed by my east facing panels.
You can just load your address in Google maps and change the map type to "satellite," then you can see which way your roof pitches point. You can also load a compass app on your phone.
My house faces EAST/WEST. I submitted a plan for 6 east-facing 405-watt panels and 22 west-facing on the rear of my home. The 6 on the front (east-facing) is for aesthetics to my HOA and neighbors and the fact I could only squeeze in a few more panels given my roof design so I didn't want to push my luck with neighbors and HOA.
Just don't expect to get very good performance in the winter.
Another thing to consider , is morning or afternoon more cloudy during the season of concern.
Right, for instance, in some climates it rains every afternoon.
Panels work better in the morning when colder SE but are more needed late in the day SW
Interesting :)
I realize this video is a little old and I may be missing something from another video, but I have two questions: one have you considered or tried one of the array set up that will let you track the sun, will let the panels turn and follow the sun? And secondly have you tried any 400 W panels? Seems like I may have seen one of your other videos that you did try 400 W panels and I’m definitely interested in starting out with some 400s to maximize my return on everything.
The equipment to track the sun costs more than just adding additional panels. The wattage of the panels doesn't change the power profile throughout the day. Having panels facing SSE and SSW regardless of their wattage will broaden the power curve throughout the day similar to what a tracker would do.
Thanks for this very useful video, l've 8 solar panels connected in series,
Is it possible to splits half of the array towards SW 20° , SE 20°, will it cause a problem to the inverter , will Amp flow towards dimmed panels??
It depends on your inverter. If your inverter has two MPPT inputs and the new strings are within the voltage range of the inverter input, than you should have no problem. If you're not sure, just contact the manufacture and they can tell you what your options are.
Did you do the metal roof building for your friend yet? I have a shop (28x30) with with a roof exposure that is SW and wanted to put panels on it. BUT I am not sure the best way to mount to the roof and not have leaks
Yes, it is complete I just need to finish editing the video. We used a similar mounting system as what I used on my shed. The difference being, we removed the screws going through the tops of the corrugations and replaced them with the EJOT cupped washer lag bolts. I should have it finished in about 6 weeks.
East West you want panels almost verticle which makes it ideal for wall mounting. What would be a cool test is bifacial panels mounted vertical East West.
I'm working on a plan to test that.
My 5.6kw are put on a set rockers where several times a year I can change the angle of the panels to the sun. this gives around 18% MORE energy i can use!!! try that.
Great video as usual! Have you tested vertical, bi-facial, east-west oriented panels as an adjunct to south-facing panels? Seems like that might optimize winter sun and smooth the daily output.
Yes! You can see the initial results here: ruclips.net/video/5AVO1IyfA9M/видео.html
If you put solar panels at a 70-75 degree angle in Winter for max production... In summer you need 20-25 degree angle and In spring and autumn you need 40-45 degree angle for maximum production
Well if your intent is to build a system that spreads out the power distribution of your panels, then build a quarter circle with them that follows the path of the sun.
That way the panels spread out which ones are getting full sun throughout the day.
I am convinced that the best solution is to have zero panels facing directly South.
For Summer the best orientation may be something like half facing Azimuth of 120 degrees and half facing 240 degrees. For Winter half facing about 150 degrees and half facing 210 degrees. For Spring and Fall half facing 135 degrees and half facing 225 degrees A mounting system that can be rotated 4 times a year to do this would be fantastic
Yes, it's unfortunate the ideal azimuth and tilt for summer and winter are so different, but with a bit more data I think I can find an optimal balanced solution without requiring movement.
I found that I can be at float by 8:00 with 8- 240 watt pannels facing east and 8 facing south and 20 now facing slightly north and 5 facing west. Lots of clipping but with 2 - 48 volt forklift batteries I'm at 96% in the morning and just run on pannels all day. I live in Arizona and summer time the sun comes up in the north more each year. I can tilt 20 of them towards the north now so I don't lose anything. As long as I'm at float in the morning I'm good. I feel the bigger the gas tank ( batteries ) is the ticket. No more generator.
The difficulty with eliminating the generator is in most cases it significantly increases the battery bank size needed for the situation where there are several cloudy or snowy days in a row. What is the usable capacity of your forklift batteries? Did you buy them new or get them used?
The angle seems to also be optimize for summer.
Where I live it's 30° in the summer, 40° in mid season and 50° in the winter.
I guess if you want to optimize morning and late afternoon you might want to raise them a bit more as well.
Its counter intuitive, but when the panels face E or W, the output is better when the panels are more horizontal. You can run several scenarios using the PV Watts calculator and see the result for your location here: pvwatts.nrel.gov/
@@ProjectsWithDave ok, that's good to know.
Other recommended higher angle, but maybe diffusion or other effects are not take into account 🤔
If you are using bifacials, a steeper angle will likely be of some benefit. You also want to consider what time of year you need the most power. For instance if your demand is higher in the winter, bias it towards the steeper angle.
Have you considered adjusting the RAILS rather than the panels?
If you assemble the structure on a parabolic (railroad) track, using rollers on the structure legs, you could manually or mechanically (solar motor powered) adjust the optimum angle daily, weekly or monthly, by the equivalent of 1° laterally per day, and reverse it after each equinox.
It's cheaper and easier to just add additional panels.
Good stuff!
Are you connecting panels facing different directions to different strings? If not, what is the penalty of this configuration?
Another issue: the goal that you want to achieve is not quite clear. Total maximized production over the year is the equivalent to lowest LCOE. LCOE does not appreciate the fluctuations in value during the day and by the season. I understand that you follow 2 approaches to address this. First, by flattening the curve during the day, and second by flattening the curve over the year. In both cases you are avoiding storage cost, whether locally or in the grid (seeing the grid as virtual storage).
I think that calculating the effectiveness of the system should explicitly consider your load profile. Primarily with your own demand, but more generally with your grid‘s day-ahead price. In some EU countries we can pool production and demand with peers at the same substation, which levels out the fluctuations in the demand in a range of a few km.
Given that January PV production is only 20% of max in central Europe, the winter kWh is more precious than that in the summer. Considering this, putting panels flat (7-12 deg) would optimize ambient light on days with low irradiation at the cost of a lower LCOE. It would also help on rainy days.
This requires a more complex model, and I have not figured out the math yet, but my anecdotal evidence from initial calculations shows that there might be a route for a demand-aware optimization.
As with anything solar related the individual circumstances are critical in determining the best strategy. My production objectives might be different than yours, but hopefully you can use my data to draw conclusions to help you achieve the best solution for your situation.
pretty nice fluke solar meter shown in another video... i used a heavy solar power station to check my used panels before buy.... played a bit with angles to get familiar with production before buy em .. funny thing is my measurements were ruined because it was too hot and while i was tired of the whole process . those panels started to burn and reduce production from, next to another . funniest thing is i throwed em on my trailer thinking . WHAT the HECK they are all from same park array . what could go wronk.... . nice video .. didnt help me a lot cause i still need to have both east and west (europes angles) arrays for the off grid charged batteries!!! . but i got the idea of best performance of an array
I'm glad it was helpful. Having the irradiance meter is necessary to be able to compare panels to each other. Temperature can have a significant impact on performance so I try and take measurements at similar temperatures. Used panels from the same lot can vary significantly, it's good you check each one. I have seen as much as 30% difference in output.
What if you mounted the four arrays on a dual axis mount that should balance morning evening production as well as more power during the day
I'm trying to avoid the cost and complexity of moving mount systems.
I'm looking at the ECO-WORTHY dual axis solar tracking system, after solving my problem with my pumps.
Roger
I am unsure which direction for a 5kw PV system. Hopefully some one knows about California's PGE NEM 2. I applied for NEM 2 and expect to be accepted. Given that, some recent solar installations nearby, ground mounts that can be installed in various directions, seem to vary. Some face less than SW, and the most recent one is closer to South. My install will have no shade issues and can be placed in any direction. Should it be directly South or ? Again, this is NEM 2.
Both PVWatts and the SMA Design Tool claim the highest production is South. Just confused why other systems are not South and yet installed by professionals.
All things being equal, the highest production will be south. There can be many reasons for facing some other direction. If there is a price difference in electricity in the afternoon for instance, you may be more profitable to point SSW or SW. This will reduce your daily production, mostly in the winter months, but may still make more sense financially by shifting production into the more profitable hours of the day. In off-grid situations, you may choose to have two arrays, one pointing SSE and one pointing SSW to reduce the number of hours during the day you have to rely on batteries or supplemental power. Each situation is different, it depends on your goals.
Hello. Is there any calculator that let me draw a square and tell me where is best to place solar panels? My south-oriented side of the roof is not that big so I'm looking to place some on east or west, but dont know where exactly. Also, my house is placed at about 20 degrees clock-wise compared to N-S line and the roof has 4 sides, each having the same 20 degrees.
East is 20 degrees clock-wise vs E-W line, South is 20 degrees clock-wise vs S-N line and west is 20 degrees clock-wise vs W-E line.
Given all the conditions I think the best placement would be all i can fit on South side and the remaining on East side.
PS: I live in Timisoara, Romania, 45.72 degrees north.
Yes, you can get some helpful production analysis for each direction from this website: pvwatts.nrel.gov/
Also watching this video on sizing your solar system may help: ruclips.net/video/rbFnZqA0GCI/видео.html
My house faces east by south-east, so I have roof surfaces facing ESE and WSW. I worried that this would not work for solar, but your video has me wondering if it would work better than I think. I have full shade from the west in the afternoon and from due south, in the summer. In the winter, when the leaves are off, the WSW roof would get sunlight shaded somewhat by a few tree tops. I know this is far from ideal, but now you've got me thinking I could probably make this work.
SSE and SSW are much better angles and when you throw shading in the mix you will have pretty low production. Realizing that, you could way over panel, maybe 150% or more to try and balance cost with production. You could run some simulations, but sounds difficult to justify.
A roof that faces ESE and WSW? Wouldn't it be ESE and WNW for a traditional roof?
Excellent analysis! How much more money will you make, or how much money will you save, with this +2% optimization if you add it to all of your panels in your array?
A 2% improvement in my system performance would only increase my savings by about $30/year. Not worth reconfiguring for, but useful for future activity.
but by putting the solar panels in a manner where their efficiency is deficient,...?
love the videos, keep up the good work!
lots of data and the one where you make bread and toast it! very good tests
Thanks!
Would u say having the panals off due south helps power production somewhat because they are staying cooler?
Heat is going to be a direct result of irradiance. If they are cooler it's also because they are getting less sun and producing less power.
Depending on how many panels are needed before you get clipping, what about of 30 panels, 20 are due south. This assumes 20 will get you to the clipping point but not clipped. Then split the remaining panels at 30 degrees or so to se and sw respectively?
Any panels facing south results in excess overlap.
Hi, you absolutely need to make sure that your panel wiring follows the sun… or in other words - where you have a row of panels - because the sun rises and falls, some panels may be in the light first… knowing that electrons move from negative to positive - ensure that the first panels to be lit up are the closest to the negative terminal of any charge controller. That way there is less loss experienced.
I rewired an east west array using this principal and more than doubled the output…
You must have changed something else, the direction of the flow of electrons is not what doubled your output.
Clipping will help maximize your output... You will get higher power at the ends of your day. You get a flat top, but that top will get there earlier and stay longer.
Just wondering if a self tracking is worth the trouble of installing?? What would be the cost over the stationary do you think? I have heard that a tracking system adds approximately 25% more energy captured vs a stationary solar array.
I haven't found a tracking system I thought was worth the cost and effort. My goal of optimizing performance vs cost usually rules out tracking systems pretty quickly. Also, I hate maintenance, I see it as a tax on my time and I expect tracking systems would require more maintenance over the long rung than a fixed system. It's easy to add 25% more performance with a few more low cost panels.
@@ProjectsWithDave As true as that may well be I have seen quite a few home built self tracking systems displayed on the internet that do not seem to be labor intensive or maintenance obtrusive and seem to be quite affordable to put together.
Just Saying that a stand alone system like yours has a lot of redundancy built in with a lot of panels and it does seem that you are putting a lot of thought and effort into this build what with all of the statistical data that you are amassing over time and it does seem to have a considerable maintenance portfolio attached to it.
Just saying
Sure, I have to count all this analysis activity as "educational" : )
After watching your videos I want to test east/west at my place, before I decide to buy roof mounted or ground mounted. Is there a cheap way to monitor and log 1 panel east and one west to basicaly do what you did with your setuo. I just want to do it before I decide to buy big array
There is not an easy way to get actual data. You would need to log the data for at least 6 months to get a good picture of your situation. One way to do it on a small scale would be to use two NEP micro inverters and their data logging gateway, but that will be $500 plus the cost of the panels. I can tell you the winter production will be a disappointment for you if you point your panels east/west. I recommend doing a simulation of your situation using the calculator on this site: pvwatts.nrel.gov/
Run two scenarios, one with each of your proposed setups. Then download the monthly data to a spread sheet and compare the numbers. This will give you a reasonably accurate picture of what you will get without doing an actual test.
@@ProjectsWithDave Thank you for your answer. I have 2 years to decide, that is when my project starts. I will be renovating my house, all from the ground, good insulation, infloor heating, heat pump option, and ofc solar panels grid tie , hybrid.. This will take some time, that's why I had an idea to test it in advance, because I have time to do it. BUt yeah, I didn't find any solution that would be cheap, and will use that website to run some calculations. Only problem is that I can't place panels south, maybe on a shed, but that would be 2-3 panels. rest of the house is east/west with 50 feet of roof on each side. Only good thing is that I will be doing new roof, so I can change the angle as needed.
Yes ☀️⚡💡👍
Great analysis!
But I didn’t really hear much about optimization of the elevation of the off-axis azimuth (SE and SW) panels.. Your trial installation appears to have the off-axis panels at the same tilt as the south facing panels. But intuitively the off-axis panels should have a steeper tilt angle than the south facing panels. This seems to be true because, by definition, the sun is in the process of rising or setting for the off-axis panels compared to the south facing panels. And it seems like more steeply tilting the panels might suggest a larger azimuth angle too. Curious your thoughts.
Also, it seems like it might not be too tough to write some software to compare and even optimize an array for different boundary conditions if provided data on output power versus incident angle for the panels being employed.
Based on my analysis, steeper angels for East/West facing panels actually reduces production. I believe that is because the steeper angle optimizes for when the sun us low on the horizon and very weak. A more shallow angle helps pick up more energy earlier in the day when the sun is stronger. I'm sure there are software solutions for optimizing various setup options.
@@ProjectsWithDave PVWatts is great for modeling.
As you aren't limited to putting your panels on a roof would a three way south/south west/south east arrays be better
Two arrays, one facing SSE and one facing SSW would probably be the best in my situation.
what if you tilt the panels E & W more vertical than the south facing panels?
That actually results in less performance. The sun is weak when it is low on the horizon.
Have you thought of doing a few panels with a simple tracker (one axis is small and easy for a few panels).
I've considered it for the experimental value, but I haven't spent the time to investigate the best solution for it.
It looks like the vertical angle of all the panels is the same. Shouldn't the SW facing panels be at a steeper angle given that the average sun angle is lower?
That's what I thought would be the case, but analysis shows that the further off of true south the orientation is the more horizontal the panels should be. I believe that is because the sun is much weaker when it is lower on the horizon negating the value of making them more vertical.
One of the best YT vids I’ve seen in a while, Thanks! I’ve been pondering this very question but won’t have parts to experiment for another month or so.
Maximize the number and production of panels in your system. Then tip some of those panels slightly east and west to just eliminate clipping. Is this also the maximum production in all seasons??? Then, using one ground mount, stand-off some panels in an inverted V. So a profile like ^^----^^. Or maybe \\\\_____//// , pickup a little extra with bifacials
You have to be careful not to make a configuration that results in the panels shading each other.
If you're clipping in January then you really need a larger inverter. Perhaps 2 7.4kw inverter to handle june& July months.
What loss should i expect if my panels face 10degree westward from true south?? Tnx for comprehensive information
Almost no impact. You can analyze the exact theoretical result using this tool: pvwatts.nrel.gov/
Thank you Dave, this info is invaluable. I have 4 ground racks on order, each holds 14 panels. I am now thinking that I orientate 1 rack southeast, 2 racks south and 1 rack southwest. I have 28 450w monoPERC Trina panels on order for the south array. I am thinking of putting 28 Bifacial 450w (14 on each) facing SE & SW. I am using 2 10kw Inverters with 2 trackers each. I am in SW France and I am trying to achieve better yields in winter. Does this sound a sensible use of resources? And thank you again for the work you put in to educating us all.
If your goal is to maximize your output in the winter, it is probably better to face everything due South especially if you are using Bifacial panels. I've started testing bifacial panels and they pick up a lot more power in the morning and evening when the sun hits the back side during summer months. If you do split the angle, the way you stated above, I would point them SSE and SSW to maximize winter results. If your inverters can handle two independent tracked inputs, than consider carefully which strings are going to each inverter to balance the power each inverter is producing relative to each other and throughout the day. I would discuss the balancing strategy with your inverter manufacture before doing the installation. Hope that helps. Thanks!
@@ProjectsWithDave Thank you Dave. I can’t wait for your video on Bifacial panels. I can’t get Net Metering here, so my main aim is to expand the production throughout the whole day. We have two EV’s and one is always back late afternoon for charging, the other is always back before midday. I know I will over produce in the summertime. Thank you again for the time you put into this channel. It’s by far the best and most informative one by a long way.
Thanks for the feedback! If you are trying to expand the production towards the evening, you might consider half facing south and half facing SW or SSW. Then put one string from each array on each inverter so they both have balanced input throughout the day.
@@ProjectsWithDave How are you finding the Bifacial panels? I have a buyer for my new unused Trina 450w and can a great deal on new Longi 445w HiMo4 Bifacial panels. Just waiting on your video on your Bifacial tests before pulling the trigger.
what hardware and software do you use to record and display your data?
The hardware is NEP (Northern Electric Power) BD600 Micro Inverters on my test rig and SolarEdge P400 Optimizers on the main array. The data is processed through Excel for analysis.
I think it's important to note not to do this with string inverters unless each string together faces the same way. Ideally you have optimizers or microinverters, depending on your situation. If I was doing off grid I would do 2-3 separate arrays and definitely have slightly different angles as well.
Yes, a string inverter requires each set of panels on a single MPPT to be facing the same direction.
Find More information for this project and others on my website: projectswithdave.com
Your East/West panels need to be at a much steeper angle than South facing panels because the sun is lower in the sky. This would improve your results.
Hi,
Is it OK to mix different types of solar panels ?
I now have 2x 150W, 12V, poly panels in series and would like to add a 3rd panel. As I don't fi d the same panels anymore, I would like to add a 170W, 12V MONO panel, also in series. Can I do this without extra parts ?
Nb, the wires now go straight into my Ecoflow Delta 2 power station.
Supplement question.
Later I would like to use these setup, with the 3 panels, to also charge a fix battery using a MPPT controller.
Can I put a Y splitter to go to my Delta 2 and the other Y splitter out into the controller, and if so do I need to put something extra to do so ?
If you have multiple MPPT inputs, which your unit does not. You could just plug your current series setup into one input and your new panel into the other.
Your EcoFlow has a 60V max input. 12V panels usually have a VOC of ~24V. If you put 3 12V panels in series ( 24V*3=72V) you will likely exceed that input voltage. Please don't do that! Measure the voltage before you connect it to the unit.
If your MPPT controller can handle the higher voltage you could put all 3 in series, but the 170W panel would perform at the 150W level because it's current would be limited by the lowest current panel in the string.
You can see an illustration of parallel and series connections and the voltage concerns in this video: ruclips.net/video/ZFbKtGSkhsE/видео.html
@Projects With Everyday Dave , Thx, BUT I made a Big mistake while writing. The existing 2cpanels and also the new 3rd one will be in PARALLEL not in serie !
And I have no other external regulator but only the build in from the Ecoflow Delta 2
What is the VOC and max current rating for each panel?
Voc 22.68 V and Isc 8.545 A
If you currently have those two in parallel, you should put them in series. That's only 45V and you would get better performance.
Not sure what to say about all the analysis, just seems very overkill to me. Since my roof is west to east, there was very little choice on how to do my panels.
Most of them are on the east side, because that’s where the majority of the day sun is. But I wasn’t happy with the morning results as it took too long to get to the my panels.
So I recently put four panels on the west side, knowing that they would only get the morning light mostly. What a difference, as that was the single best move I did! Not only is there a lot of improvement in the morning, in the winter it makes quite a bit of difference. 🖖
With a roof you often don't have a lot of choice with the azimuth, but from these results you can see that catching sun from multiple sides of the roof can be a significant performance boost.