I am looking for knowledge/practical experience and advice from people who have used “ optimisers” on their solar systems.
I will be buying a system for our new home in NW Tasy. The roof has shading issues hence the need for optimisation.
I understand there are several ways to go from micro inverters,optimisers to Maxim panels.
I am not sure if Maxim panels are available in Oz.
Anybody out there in Choice land that has any thoughts?
Enphase microinverters are a good way to go, however, eliminating some of the shade producing items is where to start IMO, as even “optimised” panels produce minimal power when only partly shaded.
You can also consider using some E and W facing sections of roof to spread your generation better throughout the day to more fully utilise your own generation, rather than having the large solar noon peak produced by having all panels facing to the North, and potentially reducing shading issues as well.
Check the solarquotes web site. Lots of good information there.
Even in sunny Qld our roof has shading issues. Those that occur early in the morning and later in the afternoon, we choose to ignore.
The cost of remedy vs minimal generation gain with each string of panels was considered. Generally the system going from full sun to full shade over 30-45 mins in the arvo or shade to sun in the morning is when the generation is at a low point anyway. It might cost us 1kWh at the start and end of the day based on the inverter data logging. The council is not going to cut down the dozen or so feral slash pines on the verge any time soon.
Watching our roof shadows and the inverter internal measurements, all the panels in a string are affected to a similar degree at around the same time. Depending on which way the panels are orientated and how the shadows fall improving power output at the panels seems an unlikely outcome for our install.
Addressing peak output of the panels during the day is a different proposition. It is worth considering that shadowing can change dramatically between seasons, mid summer to mid winter. Our roof top was watched closely for several months before committing, knowing there are many tall (25-35m) trees - bush around. All has been great for the 6-8 summer months of the year. One string in our first winter is now suffering shading in the middle of the day to late afternoon. Looking at our outputs suggest we are loosing up to 4kWh per day on a nominal 5kW system. Fortunately there are only three average trees (15-20m) to prune.
Understanding not all of us have that option, it would seem preferable to have full output from a system if at all possible.
I found the Solar Quotes web site and their blogs per the link by @PhilT and also referenced by Choice an unrivalled resource for useful information.
We also considered a ground mounted frame or shed roof for our panels to be installed on where there were fewer concerns. For some that might be an option given some houses have limited roof space in good sunshine?
Thanks Mark, you make a good point of waiting to see how the sun affects the roof.
Fortunately we take up residence in late July close to the worst time of the year for solar so I will quickly be able to judge how much shading will occur. . .
You may wish to retrofit optimisers to the shaded solar string if you are losing that much power. .
HelloGordon my old friend!
Do you know if solar panels fitted with Maxim chips are available in Oz?
By the way , the hybrid solar split cycle aircon works a treat!
Good to hear the the hybrid aircon works well
As far as I know the Maxim optimised panels aren’t currently being sold in Oz due to interference with TV reception. Last I read about it was a while ago though, see:
I’ve come to talk with you again
About my solar panel chipset
I think that Maxim is a safe bet
And my vision is for power the whole day through
Now I ask you
About the best roof solar…
Sorry, got carried away.
Yes thanks I have read that . . .
I thought there may be other companies offering them.
The reviews I read indicated that the interference was only a problem when the tv signal was low. . .
We are moving to Tasy because of the hot as hell summers here now and have satellite tv so I was thinking it might not be a problem.
Trust all is well with you
I could. Possibly Tigo as they are easy to retrofit.
In hard cash the loss is $50 - $100 pa, so it is line ball on the return. I’d possibly get a better return putting the cost towards a third string on another part of the roof.
One concern of not acting is that the shading is loading the bypass diodes fitted to the panels. There is some speculation that the durability of the diodes is not assured. Although one of the common proponents of that risk are the suppliers of microinverters and optimiser technology.
I don’t intend to find out. The cost of purchasing and retrofitting 3 or 4 optimisers to get back some of the lost output is about the same as paying to have the trees pruned severely. Less if I am feeling inclined to do it myself over a couple of afternoons. After which the second string will not be compromised until late afternoon around 4pm when the system is at low output. It is an interesting lesson.
I wonder just how many installed PV systems have significant losses due to shading and poor decisions by the installers. When our installer discussed the possibility of some shading, I accepted that it would be more effective to address the trees.
The solar system optimisations that I would like to see are the earth moved a bit further out into a longer orbit and the moon moved a bit closer like it was in the olden days.
Moving the earth would help to counteract climate change by making it cooler, so the fact that we are doing bugger all will not matter. It would also increase the length of the year so we would all age more slowly. Moving the moon is esthetic and nostalgic. It would look really cool and there would be great opportunity for photography and lunacy.
Speaking of which, as with economic fluctuations (that nobody understands much less controls) that make some apparent improvement to our lives, there would be plenty of scope for our Fearless Leaders to claim responsibility for these optimisations. By the time the tidal fluctuation went bananas and flooded coastal cities they will be out of office and able to blame the other guys. A real win-win if ever I saw one.
Oh, one more thing, how about we make Pluto a bit bigger and regulate its orbit so it can be a planet again. Another vote winner. I think I will start a Go Fund Me page…
I purchased a top-end system a year ago. I don’t have a lot of suitable roof space so went for high-capacity panels (LG Neon R 360W). I also opted for SolarEdge DC optimisers and a SolarEdge HD Wave inverter, with a SolarEdge meter for monitoring.
There is a question around the failure rate of SolarEdge P370 DC optimisers and perhaps it relates to optimisers of a certain vintage. A Qld-based installer has written a brilliant blog which includes coverage of this issue: https://mcelectrical.com.au/blog/solaredge-inverter-optimiser-review/
In my case, two of the optimisers failed within a few months of the installation. From memory, the first of these failed within the first month. SolarEdge promptly replaced them but I had to rattle the cage of my installer to get out here to replace the parts. Although they were not obliged to do, SolarEdge covered the labour costs for the replacement. Nonetheless, there is unlikely to have been much in it to compensate the installer, given he had to come out to replace one part, which is probably why he dragged his feet somewhat.
The inverter went belly-up last month and was similarly replaced under warranty with SolarEdge also covering the labour cost of that replacement. With more preemptive cage-rattling by me, the installer replaced it within a week.
I went for optimisers because I have a small shading issue during a small portion of the day from a roof finial and an antenna that I did not want to move. I also asked the installer to offset the panels a little to minimise the shading risk.
I’m still happy with the system. It “blitzes it” during the warmer months and does well in winter also, with the exception of those days in which everything is shrouded with low cloud and it rains constantly.
However, the failure rate of the three components would make me think twice about what is supposed to be a top-end brand.
I certainly paid a top-end price: $15,500 for a 5.76kW system (which included some provision for a difficult roof, and the installation of a switchboard, making the pre-existing switchboard a sub-board and some tilt-frames on the north-east-facing roof to orient the panels more to the north). I also asked for 6mm DC cabling and 10mm AC cabling to minimise cabling losses and any risk of RF interference.
Thousands of systems are poorly located and suffer shading not only from trees, but also TV antennae, satellite dishes, vent pipes, other parts of the roof, awnings, nearby power poles… the list is extensive!
CEC certification of installers is meant to mean they know how to avoid this sort of thing, but there are plenty of truly abysmal installations out there in PV land.
Yes, it was a great read. I’ve read other content on their site previously.
MC Electrical also have a very interesting blog on the TIGO brand of optimisers. This is what I was offered for our house last year, however the added cost on 12 panels of approx $2400 was hard to justify on a $5,000+ spend.
There are some very relevant comments in that blog contrasting the different products.
Microinverters are also worth consideration for difficult rooftops.
None of these solutions restore full capacity where there are losses due to poor roof orientation and shading issues. They simply limit the extent of the losses, making a bad situation not so bad.
Of course we would all expect a competent and reliably solar installer to be upfront and honest about each design with their offer?
Reality can be very different, which is why it pays to research and ask lots of questions before diving in! A 5kW system with 6.6kW of panels may only perform equivalent to a 4kW system with 4kW of panels.
Roof orientation, as well as shading can make a big difference. Solutions to deliver the power promised including optimisers, or microinverters, or even another string of panels if you have the roof space all add cost. Fine if you can afford it, but less likely to be offered by sales for fear of not getting an order.
With limited roof space the options are limited!
I do wonder about the explanation of the cable sizing. It is not something the average householder would specify?
With the amount of information on solar that’s freely available on the Internet, the average householder - like me - can access a trove of intelligence. In the week before I contacted solar installers, I spent my 4am-6am timeslot before work researching all of the minutiae on solar. Hence I learned about cells in a panel being connected in series (ergo the impact of shading a cell), string arrays, individual panel monitoring, panel orientation, panel tilt, inverter heat tolerance/location, problems with top-entry conduit and water ingress, DC isolator switches, RF interference from low-end inverters with inadequate shielding and so on.
For anyone with a need to minimise RF interference from PV system Inverters, the following offers some background info.
The high speed solid state charge pump design principles used in PV inverters are also found in many common household items, from computer power supplies through to high powered split system air conditioning.
Depending on the length of the cable between panels and inverter, and the max current from that string (close enough to the max current rating of a panel in the string), going from 4 to 6mm is typically only likely to make a small difference, maybe a percent or 2.
It makes sense for a very long cable run, but for very short runs up-sizing the cable may never pay for itself.