Solar panels are installed differently based on their geographic locations throughout the world. The premise behind this is simple; the sun is in a different place in the sky, so panels need to be directed according to this positioning. The ideal situation is when the sun is hitting the panels at a perfectly perpendicular angle (90°). This maximizes the amount of energy striking the panels and being produced. The two factors that such an angle is controlled by are the orientation (North/South/East/West) and the angle of the panels from the surface of the Earth. So in Australia, what angle and orientation are best?
(Get a free comparison of solar quotes of the installers who operate in your area!)
Tilting
The tilt involves primarily the angle that the panels are facing up into the sky. On a flat roof, the tilt is 0°, whereas if the angles were to be facing a wall, it would be 90°. As indicated in the above diagram, an angle of approximately 32° is the best, but anywhere between 20° and 40° is optimal for around a 90% efficiency. As soon as a panel is tilted below 5°, efficiency will become an issue, as well as if it is placed at an angle larger than 60°. All in all, tilting is an important factor, but not as important as the orientation can be.
Orientation
Australia, being in the Southern Hemisphere, experiences a sun that is predominantly coming at us from the North. There is of course deviance throughout the seasons, but ideally solar panels should be facing as close to true North as possible to reduce the impact that the Winter seasons have on efficiency. Once again referring to the graph above, one can see that even North Easterly and North Westerly facing panels will be largely operating at around the 90% of their rated outputs. However, once angles start approaching East North East or West North West orientation, the numbers start reducing rapidly. A directly East or West facing panel will never operate at better than 85% of its rated output. To put this in perspective, rather than getting back the usual 4.5kWh average daily energy per 1kW of solar, the system will only produce 3.835kWh. For example, a 3kW system would lose a full 2kWh a day if it were facing more East or West than North. This would equal 88c worth of surplus energy in QLD and SA a day, $1.20 in surplus to Victorians, a minimum of $1.00 less in the ACT and $1.20 in NSW. A lot of energy that is not captured, and a lot of money that is wasted.
Read more: East vs West orientation for solar panels; which side is better?
Why tilt frames are a justifiable expense
So we can see that both of these factors are important in their own right. What the majority of houses and installations need to remember is that a combination of a not so great orientation and a poor tilt will add on to one another, making the consideration of both factors the only reasonable way forward. Tilt frames that counteract a sub-optimal tilt and orientation will cost you a little extra. How much will depend on how many panels make up the system, and how the installer sources and prices the labour and parts required. The bottom line is that the bigger a system is, the more justifiable that expense becomes. With a 1.5kW system and below you can get away with forgoing the frame, but anything larger and the fact is that the cost of a tilt frame will be paid for with the increased efficiency and day-to-day output of your system. Shopping around to get a number of quotes is the best way to find a reasonable price for the frames, but expect to pay a minimum of $400-$500.
Jarrah Harburn
Solar Broker
Solar Choice Pty Ltd
© 2010 Solar Choice Pty Ltd
{ 133 comments… read them below or add one }
Is a tilt frame done as 1, or for each individual panel? eg 60 panels 1 frame or 60?
Hi Wendy. Tilt frames are made to accommodate different numbers of panels, but always in multiples. Exactly how many panels fit on the frames depends on the installers approach to the framing, but it will certainly be influenced by the location of the system and the roof/ground layout. If you have a tilt frame cost provided to you on a Solar Choice Quote Comparison, then that cost is for the entire system to be placed on the tilt frames.
can we install a east facing systems and west facing on one inverter or will there be parasitic load from one system. Thanks Greg Taffe
There shouldn’t be any parasitic load/losses in the system as long as the inverter is appropriately sized.
I am about to install a 2kva system on the western roof what out put should i expect from this type of system, your assistance is appreciated regards Brian
The output depends on the Peak Sunshine Hours (PSH) hours during the day and when they occur. if you can find out the PSH that your roof is exposed to just multiply that by 2 and that should be the amount of Watts/day you should be receiving from your solar panel.
The optimum tilt angle also depends on latitude. The figure you have provided (which you did not create nor have you referenced) is actually for Sydney’s latitude 34 degrees south. This entire figure will vary depending upon latitude. I can provide others for each city if you wish……
I have a 1kW system that even in winter seems to be averaging about 4kWh despite the rainy weather in NSW. They are facing slightly NE so I notice at this time of the year the yield decreases rapidly after 15:00. I have just ordered expansion to 10 kW
1. Should we change the fixed angle more towards north? Would it be worthwhile?
2. Are there automated systems that alter tilt during the day ? This may be worthwhile for 10 kW???
Hi Wilbur – a due north aspect for the panels would be better than NE, and if you ever had to choose NW would yield slightly more than NE.
Tracking systems aren’t easy to come by in Australia at the moment, but there are a couple installers in our network who have supply agreements in place for this technology. A good tracking system can increase efficiency by up to 30%. Please email your phone number to sales@solarchoice.net.au and we’ll steer you in the right driection.
I am about to site a building where due to the view I am wanting to orientate the building more NW rather than N. What is the maximum degrees I can twist it before it effects solar panel performance?
Firstly, for every 15 degrees you move the roof ‘off-north’ you loose about an hour of sunshine assuming that in your location the sun rises and sets in front of your house. However, the bigger question is will you have a traditional “^” roof or a flat roof? because if you have a flat roof then it doesn’t really matter.
Read you article, What is your opinion on spliting panels using one inverter. I have a small roof and it may not take all the panels
When you split panels to the same inverter wire losses and wiring safety standards can become an issue, the options are:
- A complex wired system with wire losses
- Two inverters (expensive but efficient)
- Ground Mounted Panels with or without tracking
I recently had a 1.5kw system installed and the installation was done with the panels facing East instead of North. The midday sun would have been directly above the panels had they been installed on the northern facing roof, however, the installers said that east was better because it is getting the morning sun which is the most productive. I have noticed however, that after 3.30pm the panels are already in full shade whereas the northern roof is still in full sun. Can you advise on how I can measure if the panels are performing properly and what my next course of action should be?
Cheers
If you want to measure the performance of your panel and compare it to what it might be if they were on the north facing roof one option is:
- get a pyranometer which measures how much radiation a certain point receives from the sky during the day
- collect the data over a day (once every hour) for both your north facing roof and your east facing roof
- add the numbers together and which ever roof has a higher total (receives more radiation over the day) is the better roof to have your panels on
I’m just inquiring to the figure you provide showing optimum tilt angle and orientation, do you have a reference for where you got that diagram, or did SolarChoice (You) create it???
The figures are something that we gather from talking to the system installers and the solar panel manufacturers i.e. conclusions drawn from real data
hi, what do we do, so many people give conficting advice on where to put our solor panels. We only have room for 6 panels north and we could have east or west as well , some say all east , I guess that looks easy to do ,we are so confused it makes you want to forget the whole idea, what do you suggest, help.
When you face all panels east or west are you able to increase the number of panels that your roof can fit?
If you can only fit 6 panels on your roof in total then you should face the panels north to maximize sunlight exposure, unless there is shading. Shading will also play a role in whether your panels should be facing east or west. Is there any shading on your roof during the day?
So my roof is in ^ shape and the roof is facing west and east.
Is it still making sense to install the 1.5kw system? I have read your article.
Hi Tom,
there are several options for a roof like that. One of them is a raised installation where the installation is built on one side but is higher than the top point of your “^” shaped roof. The other option is ground mounted installation. Sometimes, despite having north facing roofs, people have trees or buildings in the way of their homes which restrict the number of direct beam sunlight hours that the panel receives.
It really depends on what state you are in, with respect to feed-in-tariff rate, and whether it matches your expectations of payback period.
Alternatively if you are in a ‘time of use’ state it might be useful to have them on the roof which faces the sun during the higher prices of electricity.
Installers are required at law to comply with the Clean Energy Council’s directions on the mounting and orientation of SGU’s. All installations must comply with the Clean Energy Council accreditation requirements. All accredited installers are required at law to comply with the Clean Energy Council’s regulatory requirements outlined in the their code of conduct. Go back to the provider/installer and request a copy of the documentation they lodged with CEC, and a copy of their accreditation documentation. Do not take no for an answer and contact General enquiries: info@cleanenergycouncil.org.au
Hi,
I am confused. I am presently in the process of having a 2.2KW system installed which will be connected to the grid (NSW). The installers have started to install the 12 panels on the roof of shed (best direct sunlight). The apex^ is facing north (slighly east by 10-15 degrees). So the installers have postioned two banks of 3 panels (one behind the other) on each side of the apex (6panels per side, total 4 banks of 3 panels each, panels facing north). The 2 banks (total 12 panels) each side of the apex do not receive total sunlight all of the time (one bank in the morning 6panels , then both 12 panels and then one6 panels in the afternoon). I am wondering how these should be wired (I will have a 3kw inverter) for best performance ? The installers were not sure when I asked. this worries me.
Regards Steve
With regards to wiring it doesn’t really matter weather you keep the panels in parallel or in series as long as the wires are not too long because the wire losses can add up really quickly in a parallel system because the wires have to be of equal length. With regards to inverter sizing have a look at our post on inverters, this should be a good place to start: Click Here
Are all tilt frames for solar panels adjustable between certain angles?
My solar HWS tilt frame was welded solid at a fixed angle.
How high off a flat roof would the top of a panel extend?
Usually this is something you can discuss with your installer when you install your panel. However with solar hot water systems the difference in performance is not that great given the seasonal change in the angle of the sun.
With respect to your last question it depends on how big the panel is and then the standards for wind loading for those dimensions.
I am considering installing solar panels on my North facing roof.
I live 150km East of Melbourne. [About 38degS]
What is the optimum roof angle for the panels?
It depends on whether you want to maximize your production during summer or winter or have an average production through out the year.
Summer = 38 to 48 degrees
Winter = 48 to 58
Average = 43 to 48
it also depends on what type of shading you might incur on the panels if you have more than one row of panels
It does not make sense that you are advising to tilt the panels 32 degrees when the earth’s tilt is usually less than 24 degrees and depending where you are in Australia the angle of tilt of the sun from the north is much less then this? If one is not going to track the sun from East to West, surely just leaving the solar panels perfectly horizontal is the best option, specially as when you are situated in the northern regions of Australia?
Thanks for the comment, Solomon. You’re right that in the tropics it is usually advisable to keep panels horizontal, as the sun moves from north to south throughout the year. In the non-tropic parts of the country, though, the angle will differ, but will always face north. If you have a system installed on your home, your installer can give you more detailed advice relevant to the particulars of your latitude.
Could you please advise whether or not a tilt frame would be required for a solar panel 1.5kw installation, where the orientation of my roof is due north and panels laid flat on a metal deck roof which has a 3 degree fall east west ? The installer has advised me that the system should acheive an 87% efficency. Would this be correct? I have my doubts after reading your notes in regards to “Tilting”. The installer now tells me that they didn’t allow for a tilt frame and if I wanted such there would be an extra cost of $1000. I would have thought that the Company (so called experts) would have advised me of this at quote stage. What should I do?
Thanks, Karen
Can you please clarify what is the direction of your solar panels and what is the angle that they make with respect to the ground. You will need a protractor and a long ruler to measure the angle.
I am trying to find out the exact explanation why the longitude and latitude are of importance to the tilt of a solar panel
Rodney, this is based on the tilt of the earth’s axis. The earth rotates around the sun on a plane, however on this plane, our north does not correlate to the theoretical north of the sun. This means that at the equator we do not see the sun as directly over our head and therefore we have to adjust for this. As you move north or south of the equator this angle will continue to vary because the earth is a sphere and not a flat surface, thus the latitude effects the angle at which you see the sun. With respect to longitude there is no correlation with that and the tilt of a solar panel.
i am in Ghana which is in the tropics and i would like to know the best orientation and tilt for my solar panels
Hi Agamah – SolarChoice also has branched out to have a presence in Kenya – http://www.SolarChoice.co.ke – a country that straddles the equator. Panels there are laid horizontal – flat is the optimal angle, as would be the case for Ghana.
I have a 2.22 kw system installed facing north with nil shading problems however after installation it was “discovered” that the roof pitch was 41 degrees. (30 in the quote) So far this month (mainly fine/sunny) I have averaged approx 7.5kwh per day. I have approached the installers suggesting that if the tilt was changed to 30 degrees that it would greatly increase my daily output at least during the summer months however they seem to believe that it would only increase the output by about 1 or 2 %. What are your thoughts on this suggestion?
Hi Kevin,
For a system of that capacity you should be producing more power–depending on your location, possibly 9kWh per day. (Incidentally, where are you located?) The tilt angle can be quite important in power production, and generally we recommend that a solar panel array at 32 degrees latitude (Sydney) be angled between 15 and 30 degrees (facing north, of course). If you are at a higher latitude (i.e. closer to the south pole), the angle is usually set a bit higher to take advantage of the low angle of the winter sun.
I have a less than optimum roof orientation. 15 degrees facing e-ne. What would be the most cost effective change I could make to gain sun exposure for winter improvement. am 41 degrees south. Only 1.5kw unit so if the expense is too much may need to not install. Iron roof.
Any ides?
John
One question. How many degrees south is your model based on?
John
im in rockingham wa.just had a panel designer come to my place and he told me nth east not nth is the best way to face the panels.because with the extreme heat in wa the panels will actually lose power when the temperature gets over 36%(not sure of the exact %)also spring and autumn produce the most power.is this true?
I am thinking of getting a 1.5kw system installed on my roof but the only way it can face is East is there much point ?
Hello Bianca,
You could still potentially benefit from having a system on an east-facing roof–In the southern hemisphere it’s south that is the no-go zone. Give us a ring on 1300 78 72 73 or fill out a quote request form on your homepage (www.solarchoice.net.au) and one of our brokers will get in touch with you and help you hash out the specifics! Good luck.
Hi this is Steve from the entry 17Nov10.
My system as above 12 panels (2.2 kw system) is divided into 4 banks facing is finally up and running as of 03Feb11. The best day in full sunlight was 10kw. At it’s best (mid day in full sun light) it peaks at only 1700w for 20minutes. This seems a bit low. Today I will be lucky to get 6KW a few clouds today. I am wondering that because each bank of 6 is (2 banks of 3) is slightly facing away from each other I am losing power production.
Your thoughts
Regards Steve
Hi Steve,
Thanks for the comment. It could be possible that you are losing a bit of power because of uneven distribution of sunlight on the two banks of panels, but that really depends on how the banks were wired. If they are all wired in sequence (meaning that they’re all essentially in a row on the same wire in a ‘string’) then any shading or irregular insolation (sunlight) could affect the current of the string, much as minor shading would. Even if the banks are wired in parallel (meaning that the current of all three would add up), although the reduction in production would not be as pronounced as with an all-sequential (single string) setup, there could still be a reduction because only one panel at a time will be getting perfect insolation. In any case, you might want to talk to your installer about the discrepancy between your rated capacity and the actual output of your system.
Also, you say that ‘the best day in full sunlight was 10kw’. By this, do you mean 10kWh? The difference between kW (capacity) and kWh (electricity actually produced) is a big one, so be careful! Was that just a typo?
Hi
I like some advice on siting panels if posible.
We are about to have installed a 3 kW (16 panels) system using a 2 x MPPT inverter at our tiled roof house in Perth. The orientation of the house is not ideal as the block front faces exactly NE. I have two options for panel installation, all 16 panels installed on the garage roof which faces NW or split the installation and have 8 panels facing NW on garage and 8 panels on front of house facing NE ie on separate channels
Any advice is greatly appreciated
Thanks
James
Hi James,
Due north is the best direction for panels to be facing (in the non-tropical southern hemisphere, anyway!), although even this is not ideal, as the sun moves through the sky during the day and even a north-facing array will therefore receive varying amounts of sunlight throughout the day. If you can afford the panels or aren’t concerned about a slightly longer pay-back period on them, it might make sense to spread them out across the two roofs as you have indicated you are considering. The MPPTs will certainly help up the efficiency of the systems, especially considering that you are unlikely to be producing optimally from the NE-facing array in the afternoon and the NW-facing array in the mornings.
Hi, I live just North of Brisbane and our 1.5kW system faces slightly east of North (less than 5 degrees) on a 22.5 Degree tile roof, but I have never yet seen it put out more than 1000 Watts (On the inverters own meter). During summer the sun is almost directly overhead of us so i would think that tilting the panels to say 3 degrees would give better efficiency during summer having them at 22 degrees Autumn and Spring and then about 40 degrees in Winter would provide optimum efficiency. I cannot find any information anywhere regarding the loss of efficiency per degree off perpendicular radiation for solar modules. Just trying to decide whether it is worth the effort of building a tilting frame, maybe I will automate it! What do you think? Thanks, James
Hello James,
A tilting frame would indeed help your efficiency, but also introduces moving parts and extra maintenance into your system, which could cause headaches. If you are mechanically-inclined and have the time and means, it might be an option to put in the tilting frame, but for most people it’s a bit of a hassle.
Incidentally, there is a fantastic resource here, where you can calculate the best angle to put your panels at relative to your latitude. Just keep in mind that in the animation the maximum solar incident (sunlight) is arbitrarily set at 20, so you’re not looking at even percentages, but rather a ratio of 1/20.
I’m in the northern suburbs of Melbourne living in a double storey house keen to generate as much solar power as I possiby can.
My north facing roof space is limited (2x panels downstairs + 2x panels upstairs = 4 panels). The tilt is nice at about 33 degrees.
I could fit another 5 or 6 on a west or east facing roof.
The west facing roof MAY suffer from shading from next door neighbour’s tall tree, while East side is clear. Is East facing appreciably worse than west ?? Or would I be better going East with no shading than west with some possible shading ?
I’m doing my calculations assuming that north facing panels will generate 90% of the rated capacity and the west facing panels genrating 75% of their rated capacity. Does this sound reasonable ?
Any thoughts re possible configurations. It sounds like with a mixture of Panel locations, the method of wiring becomes important !? Anything else you can advise regarding this ??
Is it even possible that I’d be better off putting all panels facing east rather than a hotch potch of North and East ??
Hi Mark,
Thanks for the comment. As mentioned in the above article, the trouble with E/W-facing roofs (both directions should receive roughly the same amount of sunlight) is that the will really only produce a significant amount of electricity while the sun in shining down on them, which is only about half the day (i.e. once the sun has crossed the apex line of the roof, you’ll see a significant drop in production. The E/W-facing panels will most likely generate well during the periods of direct insolation (sunshine), possibly at up to 85% of their rated capacity, but due to the shorter periods of production, on average you will see them producing significantly less than their updated capacity; you might see an even more dramatic loss in the winter months, when the sun is further away but you actually use more electricity. This will drag down the yearly average production. It’s up to you to decide whether its worth it to install the extra panels. You could give us a ring on 1300 73 72 73 or fill in this online form and one of our brokers can give you a detailed quote comparison explaining your different array options.
As for the wiring, if you go with the multiple-array setup as you’re thinking about doing, it would sense to have the panels on separate strings. If they are all on the same string the current of your entire system will be dragged down by the underperforming bits (i.e. E/W-facing panels when the sun is not on them.) You might even consider multiple inverters to keep detailed track of how each string and the system as a whole is performing.
hey mate like ur site .i work for a mob in sydney n there tryn to tell me west facing panels rather than east wat u reckon.bit confused without suneye
Hi Brendan,
East vs West depends on where you live–if you have a lot of cloudy mornings (i.e. dawns where the sun is obscured by clouds), as is the case in Sydney, west-facing panels would be a better choice because the setting sun is obscured less of the time (there are fewer cloudy afternoons than there are cloudy mornings.) If you lived in a place where there were almost no cloudy days, it would make no difference whether you put your panels on the east-facing or west-facing roof, though.
I have contracted to have a 1.52 kW system installed on a roof that faces just a few degrees north of east – with the risk of some shading from an air-conditioning unit and a solar HWS. Since signing the contract, I have looked at ways to improve the situation, including moving the HWS. The idea of mounting the PV panels on tilt frames on the west facing roof appeared to offer considerable benefit – north facing, free of shading, closer to the inverter etc. However, the company ABSOLUTELY REFUSES to install PV panels on frames – Company policy – end of story! Why might that be? I’m in a southern suburb of Perth.
Hello Jeff,
Installation protocols and technical ability vary depending on the solar power installer, and companies may refuse to install frames for safety reasons (a history of bad experience with frames and associated liabilities, or just a simple lack of technical expertise, for example). There are, however other companies that will do frame-based installations. Please get in touch with us on 1300 78 72 73 to speak to one of our solar power brokers, who may be able to put you in touch with an installer that will not object to using frames in the installation.
Hi, I live in Sydney Northern side and my roof which is suitable to install solar panels is tilted and facing South-East. I have asked two companies to come have a look. The first one said that we can’t install as the efficiency is too low and not justisfy to do it. The second company said that they can install 1.5kw for us with 30 degree tilted solar panels without problem on the efficiency. I don’t know which one to trust? Can you give me some advise please.
Derek.
Hello Derek,
Thanks for the comment. A SE-facing array will not generate to its rated capacity, but it will generate some power. It might even be possible to generate enough electricity to make an installation worthwhile generation-wise, but this would require an investment in extra panels that you would not need on a roof with an optimal orientation, such as N. The amount of your investment for an array on a SE-facing roof may be disproportionate to the financial benefit, and this is probably why the first installer advised against an install on that roof.
Our solar power brokers may be able to assist you further. Please give us a ring on 1300 78 7 73 or request a quote comparison on our website. We hope to hear from you soon.
Hi, I am currently wanting to put a 4.9kw system. Our roof is facing true north at a 15 degree angle. I have been trying to find the difference in the power generated if we fix the panels to the existing roof, or whether it is worth while to make the panels with varing tilt so I can optomise the angle through out the year?
Hi Greg. Thanks for the comment. The difference in yield would depend on your location and the daily amount of sunlight that you receive there, so we can’t give you an answer here until we know more. Solar trackers, as mentioned in the article above, can improve your power yield but at the same time require more maintenance and have more moving parts and are therefore more prone to malfunction than stationary panels. To talk to someone about your options in more individualised detail, please contact one of our brokers on 1300 78 72 73. We can give you a good idea about what the price and capacity differences offered by different installers would be.
We have just signed to have a 3kw system installed. Our house roof which has a good tilt faces about 30% north east. This roof space is not big enough to fit all 12 panels. The supplier has suggested that we could put panels that wont fit on this space on the west north roof. We also have a deck roof which faces 30% north east which would hold all 12 panels but the pitch is only about 6-10%. They can supply tilt brackets at $80.00 per panel which seems like a lot? Is the pitch critical?
Hi Ken. What state are you located in? The tilt correct tilt angle depends on your latitude. As you can see in the chart at the top of this entry, if you are in Sydney (as goes for most places), the north-facing orientation is most important when it comes to performance, and once you have that right or as close to N as you can get it, it’s best to try to focus on getting the tilt angle right–in your case you obviously can’t change the angle of your roof, though. As you can see, there is a bit of wiggle room for efficiency with the tilt, especially because the sun angle actually changes throughout the year.
So your 2 options are:
a) Put some of the 12 panels on the 30% NE roof, and some on the NW roof. I presume that the roof angle is such that you won’t need tilt brackets here.
b) Put all the panels on the 30% NE deck roof, which has a tilt angle of about 8 degrees. Tilt brackets would be necessary here.
I recommend that you go to http://suncalc.net, find your location, and do the calculations for both scenarios based on your system size. Or, if you get back to me with your location, I can do this for you. It would also be helpful if you could tell me how many panels you are considering putting on each roof, should you decide to split the array.
Hope to hear back from you soon.
I have just had a solar hot water system installed, the house faces east west they installed the system on the east side could this be less energy efficient than facing west
Hi Rose,
That shouldn’t make a huge difference with regard to the efficiency of your solar hot water system. Generally speaking, west is slightly better than east, but it depends on your location. Please see this more recent article about east/west roof orientation for solar power.
We just had a total of 16 panels installed on the roof of our house. They installed them as one row of ten then a row of 6 directly below. I then had an appointment for installation at another house and the installers told me they could not be installed as uneven rows and it substantially reduces the efficiency. I seem to be told different things by different installers (I have gone through the same company however they were installed by different installers). I guess I am just after a more definitive answer. I hope you can provide some help on this matter. Thanks
Hi Amy – good question. To preserve maximum efficiency from your 2kW system you’ll need to have two of the panels in the row of 10 wired together with the six below, to effectively have two even wires of 8 going into the inverter. A 2kW inverter doesn’t have the MaximumPowerPoint (MPP) tracking capability which exists in some of the larger inverters, and would otherwise run the system “in parallel” by reducing the row of 10 panels to the output of the the row of 6.
I have had a 3kw system installed. There are 16×190 watt panels. The roof faces due north. Apart from a hill to the east which blocks direct sun for the first 30 minutes of the day I have no shadows what-so-ever. The inverter starts well at a little after 6am and generation rates climbs until just after 9am when the rate will be 2200 watts. The systems stays at this rate until just after 3pm when the sun’s intensity starts to wane. I feel the inverter is faulty as after constant watching and recording I have never seen it go over the 2200 watts. The inverter is rated at 3000 kw. A system friend of mine has with a different make of inverter will continue to increase the generation until reaching its maximum of 3300 watts around 11am. We are about 10 kilometers apart. I would apreciate your comments
Hi Desmond – it appears your inverter is only running at approx 75% efficiency, when it should be closer to 93% peak efficiency. What brand inverter do you have? We’re aware of a couple of brands which have had to be swapped out due to similar inefficiencies. If you’re in a rural area and towards the end of the line on your grid, you may be adversely impacted by impedance and voltage incompatibilities … which can be fixed by rewiring your inverter. Cheers.
Hi. Is the small red area in the above graph the area of 100% production. If so does the white area show 90% production for different tilt and orientation. Then if this is correct does it then indicates that from 10 degrees to 60 degrees tilt angle the production is still 90%.
Please correct me if I am reading the graph wrongly.
Thank you kindly
David
Hi David,
If your array is facing due north, then your observation is correct. Also, please bear in mind that the graph (from the yourhome technical manual) is an example graph, particular to one latitude (35o South), and actual efficiency will vary depending on your location.
am looking at installing a 2.76kw system with 6 panel on a north east facing roof and right beside it, installing another 6 panels on a north west facing roof. the inverter is a aurora PVI 3000 outdoor inverter. we live on sunshine coast, qld. I went out this morning at 7am and the NE roof was in light while the NW roof was mostly shaded by some distant trees. At 4pm this arvo the NE roof was completly shaded while the NW roof was sunny. With this situation, would half my system still generate half the power while the other half is shaded. Or would this shade drop the whole system???
appreciate your response
Richard
Hi Richard,
A system would generate only half the power that it would if divided up on the two sides of the roof as you have described, and with the shading you described. Ultimately, though, it would depend on how many ‘strings’ of panels you have. When you string panels together, the voltage adds up. When you string them in parallel, the current adds up. If you connected all of your panels together in one string and fed them into the inverter that way, there would be significant power losses due to shading–even partial shading of a string of crystalline silicon panels will have a significant impact on the current produced. If you are confident that the shading of the two sides of your roof is limited to only one side at a time (ask yourself if there is any period when both sides might be shaded, even partially, simultaneously–this is very undesirable), then it might be worth your while to install the system as you are suggesting.
In summary, if there is shading on either side, you can expect the electricity production of the shaded side to be sub-optimal. The losses due to shading can be minimised by separating the array into two strings as I mentioned, but you will never receive optimal production from both sides (unless you cut the trees back, perhaps.)
Also keep in mind that the shading may be different not only at different times of day, but at different times of year. A system may, for example, produce more electricity in the summer than winter or vise versa.
We can give you more advise and a free quote comparison of what systems and components are on offer from solar power installers in your local area. Get in touch with us!
Hi Found your website and it is great. I have an issue with council approval. Will cost and arm and a leg along with many weeks…as I want to put solar onto a flat roof onto tilt frames. Trying to work out the lose of power generated if I only instal it flat without tilt frames. Area is in Adelaide, SA 35 degress South. Are you able to let me know how to calculate the potentail loss if installed flat. Thanks
Hi Teresa,
We are more than happy to help. Please get in touch with us by filling out a request for a free solar quote comparison or just giving us a ring on 1300 78 72 73. We will be able to find your specific location on an internet map site and tell you where you might run into problems, and also how much you could benefit from installing tilt frames.
Hi,
I have just come upon your site. I have signed up for a 2.25kw solar system, now the company has come back and said the panels won’t fit on the north west roof but will fit on the south eastern side with only a 2% greater loss of efficiency. I find this a bit hard to believe. I would value your opinion on this. I am in Brisbane.
Hi Jeanette,
It’s hard to say whether that figure is right or not without knowing your circumstances, and whether your installer is thinking about using brackets for mounting and tilting. How far south-facing is the roof? Is it due south? During the summer months the sun does rise from the southern part of the horizon.
the roof they are going to use faces 116 degrees South East. The installer isn’t charging any more for installation so I am assuming they aren’t using any different brackets.
Thanks for the response, Jeanette. What is the tilt angle of the SE-facing roof?
the roof has a 30 degree pitch.
I appreciate the help.