low output until all panels in sun

What do you mean about the white cable? At the moment that runs to the generation meter, then to an isolator and then to the consumer unit.
 
The three connectors on the far left are positive DC inputs and the three on the right are negative DC inputs. There is a DC isolator inbuilt on the unit. No way of knowing if the cables are wrongly marked. It's just a nasty lazy installation.
How did they test each string without DC isolators - well of course they didn't. Normally if you reverse the input polarity the unit will not work but this puts out 3kw so who knows what is going on.
Is there a test report sheet in your customer pack?
 
The white cable is way too small it should be 6mm the same as you would use for a shower/ cooker supply.
 
davey_b said:
We had the system installed last September. There was issues with low output and they came back in April and looked at it and output was better. Then I noticed that when it was at peak power it would suddenly drop to 0 and then climb back to nearly 4kw. It was saying "Vac 10 min too high" and "Frequency too high"

The inverter was replaced but now this inverter is saying "Failure fan2" so I'm going to contact solarmax about this tomorrow.

It's a Solormax 4200s inverter and we have 16 Canadian Solar CS6P panels.


As you can see we're getting full sun, it's pretty much straight on the panels and there is a wee bit of shading on the end panels and we're only getting 0.37kw!
Click to expand...

Davey_B. I can vouch for that, and I have the same. It's pretty much expected as has been mentioned already. I have trees to the East.

I don't think many people realize the extent of a very small bit of shade till they see what you have there.

I did the same set of photos with mine one morning last summer, and I have a series of photographs every ~ 15 seconds as the panels come out of morning shade of a tree. I am on 2.3KWP, and exactly like your system, the reduction is massive, probably 90% loss, even with just a minute piece of shade left on one of the panels, - maybe half an A4 sheet. Loose that last leaf shadow, and Pow.. right up there!

I am on single string, some unspectacular Yingli's, and fairly conventional 4 year old Fronius, nothing extraordinary.
 
I think its hard to say exactly what is causing that as there are a number of issues that need to be sorted as others have said any shading is also a big issue in general it all needs sorting
 
Yes, that's the one. Would have been amazed if DC isolation had been excluded.
The AC side is somewhat interesting to say the least. The run to the the consumer unit is unlikely to be very long so 4mm T/E would be adequate. Without knowing the rating/sizing of the cable currently fitted it is difficult to comment further. It does however look a little small.
 
Ok so what would your list of things to sort be? That gives me an idea of what to ask of the installer.
 
The Solar King said:
Yes, that's the one. Would have been amazed if DC isolation had been excluded.
The AC side is somewhat interesting to say the least. The run to the the consumer unit is unlikely to be very long so 4mm T/E would be adequate. Without knowing the rating/sizing of the cable currently fitted it is difficult to comment further. It does however look a little small.
Click to expand...

Run to the consumer unit is about 40m because our house is a u shape and the consumer unit is on the other side of the house.

Just to clarify there is no separate isolator like the ac ones between the panels and the inverter. The cables come straight from the panels to the inverter. The inverter has a switch on the side of it which is called dc insulation switch in the inverter documentation. How though would you stop current coming down the cables from the panels to swap them over etc.? Or isn't that an issue?
 
1, install cables from array in conduit. 2, Install correct size cable from the isolator to the generation meter (either 4 or 6mm depending on calculations) 3, Install DC isolators even though already included on the inverter just makes a better job, and ease of testing, 4, Full test report on all individual panels and strings including polarity, 6, Fire proof board behind inverter 7, All warning labels system schematics to be in the right places. 8, Resolve shading issue by moving panels, optimisers etc Once all resolved you should have got to the bottom of what is causing the poor generation or could just be a combination of a few things
 
ie. an MCS approved installation following the DTI guidelines which is what you were paying for. And you need another AC isolator at the consumer unit which is not in the same "room" as the inverter. So the installer is going to have to spend cash sorting this out correctly which is most unlikely in my opinon. If it was not for the shading issue this installation would never have been highlighted. Quite how you are going to test the individual panels now is another issue.
 
With built in DC isolator not an issue. Start up and shut down procedures must be followed. Like others commenting, I made an assumption about your property from the external shots. At 40m, 4mm cable would not be adequate as the voltage drop would be over 3% where the regs require less than 1%. Therefore 6mm is required.

Please leave everything to a qualified installer.
 
The Solar King said:
With built in DC isolator not an issue. Start up and shut down procedures must be followed. Like others commenting, I made an assumption about your property from the external shots. At 40m, 4mm cable would not be adequate as the voltage drop would be over 3% where the regs require less than 1%. Therefore 6mm is required.

Please leave everything to a qualified installer.
Click to expand...

I'm not thinking of doing it myself. I just want to understand how and why so that if am told something I know if it's crap to palm me off or not.
 
Give us a broad indication of where you are in the country and one of the guys from here might be prepared to pop around and give it a "once-over". I suspect that the list of issues might grow even longer.
 
Sorry, well off our patch but the forum has a few members from north of the border who might be able to help but the general principles and standards are the same nationwide.

You've received a fair few indications of issues to raise when you invite the installer around to discuss the matter. Have you checked whether they are still trading? With workmanship like this they may have gone under rather than deal with warranty claims. Did you get an insurance-backed warranty?
 
Davey, I am in Inverness and have exactly the same type of panels and inverter as you.
I could give you a reading of what i am generating daily over the last few weeks as a comparison.
Direct Solar fitted mine and it looks like the same type of installation - Shoddy.
I don't have a hand held meter like you are holding though, if I want to know what I'm making it's up to the loft I go.
I am going to hook it up to ethernet eventually when I get round to it.
I've been getting around 20 odd KWH daily this month, with a 4kw instalation, split over my roof, e.g. 8 panels on each side.
My gable end of my bungalow is south facing meaninig my roof is an east/west split.
I thought the installers were wrong in doing a split but wonder if I am losing out when the sun comes over the top of the roof and leaves the east facing panels behind.
I look forward to reading more comments in the morning.
Steve.
 
Hi Davey_b

We are in Edinburgh and would be happy to give you a quote so correct the problems. I know Iain at Tigo so could install optimizers if required, although it may not need it.

Regards

Tom
 
pvman said:
Hi Davey_b

We are in Edinburgh and would be happy to give you a quote so correct the problems. I know Iain at Tigo so could install optimizers if required, although it may not need it.

Regards

Tom
Click to expand...


Cheers.

To be honest if the original installer (they're still trading) doesn't do it as part of the original install I'm going to tell them to come and take it away because at this output I'd be better putting the money in an ISA.
 
davey_b said:
Cheers.

To be honest if the original installer (they're still trading) doesn't do it as part of the original install I'm going to tell them to come and take it away because at this output I'd be better putting the money in an ISA.
Click to expand...

No problem, Without seeing the site it is hard to be sure but I don't think the issue is with solar, it is with the install. As others have said using PV sol overheadview1.jpgwould show shading and provide an accurate prediction on what you should generate.

Tom
 
Well, you have had lots of good advice there, but after seeing the pics, and reading all the advice, I do not think that optimisers are the answer for you, In certain circumstances they can be beneficial though.

Firstly, you need to get the two panels out of the shade, either move them or cut the trees, remember that those trees will grow so in 10 years they may shade 4 panels...
It looks like you have space to move 4, just a suggestion.

Also the install needs sorting, that silly bit of flex they have used will/can cause your inverter to go overvoltage, something that some companies do not understand, I think someone did the calcs and said you need 6mm which is always a safe size to use anyway for a domestic install.

I understand your frustration with all of this, but get the system sorted, properly, if it was working as it should you would be over the moon.

My advice would be to let the install company try and sort it, you never know they might have learnt something in a year...
 
Earthstore said:
Well, you have had lots of good advice there, but after seeing the pics, and reading all the advice, I do not think that optimisers are the answer for you, In certain circumstances they can be beneficial though.

Firstly, you need to get the two panels out of the shade, either move them or cut the trees, remember that those trees will grow so in 10 years they may shade 4 panels...
It looks like you have space to move 4, just a suggestion.

Also the install needs sorting, that silly bit of flex they have used will/can cause your inverter to go overvoltage, something that some companies do not understand, I think someone did the calcs and said you need 6mm which is always a safe size to use anyway for a domestic install.

I understand your frustration with all of this, but get the system sorted, properly, if it was working as it should you would be over the moon.

My advice would be to let the install company try and sort it, you never know they might have learnt something in a year...
Click to expand...

The issue with the trees isn't that they shade all day rather they shade all the panels in the morning and then the panels start to come into sun about 11am and then by 2pm all the panels are in full sun. Thus from my understanding optimisers would help as they would allow us to generate an increasing amount between 11am and 2pm. Sound correct?

Re the white AC cable from the inverter to the generation meter. I measured it this morning and it's 1cm (10mm) in diameter. That's the whole cable including the white insulation. Thus I wonder if the cores are 1.5mm or 2mm at the most? It's a round cable. Thus do you think this is most likely to be the cause of the "Vac 10 min too high" error or "Frequency too high" that was causing the inverter to shut down?

Thanks
 
If you examine the white cable carefully, it should be embossed at regular intervals along its length with its specification. Incidentally, has this been routed internally or externally to reach your consumer unit? (fuse box). From your description it is unlikely to be more than 2.5mm. We have never fitted Solarmax, so cannot comment on their error messages.

The issue with shading needs to be modelled and calculated to estimate what the reduction in annual output is compared with no shading. This alters from month to month with the tilt of the earth. The system should be modelled without and with optimisers to see what level of gain could be expected. If the gain is not great enough, they would not be a viable option.

Incidentally, in terms of resolving this, from the description of your property, do you have an unshaded West facing roof? It is possible relocating the array could provide better output than its current location.
 
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I'll have a look at the cable tonight. It is routed internally in the loft and then out along under the soffit outside and then back into the house.

We do have a west facing roof but there isn't enough room on it to fit the panels. I do wonder if we could fit 2 panels on the other side of the thermal panels and then 2 under the thermal panels in landscape.

Here's a better picture of the roof taken in April at 1.23pm

2013-04-19 13.23.38.jpg
 
Last edited by a moderator:
The amount of shading on that roof is immense. How far does that tree line to the right hand side of the picture extend?

Did your installer mention how much of an affect this would have?
 
It is not just the tree line. Look at how the land slopes up as well altering the horizon point. Even without trees there would be shading issues until the sun was well up in the sky. This was one of the reasons for mentioning relocation. It would also start to explain why the solar thermal array is so big.
 
We're pretty cautious and I have to say we've recommended customers don't install in this situation before. Admittedly it was before micro-inverters and optimisers were around and the cost of the array was substantially more.
 
davey_b said:
The issue with the trees isn't that they shade all day rather they shade all the panels in the morning and then the panels start to come into sun about 11am and then by 2pm all the panels are in full sun. Thus from my understanding optimisers would help as they would allow us to generate an increasing amount between 11am and 2pm. Sound correct?

Re the white AC cable from the inverter to the generation meter. I measured it this morning and it's 1cm (10mm) in diameter. That's the whole cable including the white insulation. Thus I wonder if the cores are 1.5mm or 2mm at the most? It's a round cable. Thus do you think this is most likely to be the cause of the "Vac 10 min too high" error or "Frequency too high" that was causing the inverter to shut down?

Thanks
Click to expand...

So, you are losing about 50% of max production per day in the summer, it will be worse in the winter as the sun is lower in the sky, therefore shading more panels.

It is highly probable that the "flex" they have used is causing the error codes mentioned, due to voltage drop.
I will try and explain, let's assume that your incoming voltage is on the high side, say, 250V, and at full power the Volt drop is 15V down your "flex", then for your inverter to match the mains voltage (well it has to go slightly over to push your PV power back into the grid), your inverter will have to raise it's voltage to 265V+, therefore exceeding it's set parameters causing it to produce the said fault codes.
This is just an example, and with some facts all of this can be calculated, but I hope this example gives you the understanding that you need.

Also, a little more technical this, your inverter may well be working on a particular input range from your panels, then when the shading clears, sometimes quickly, your inverter is still looking on or around the original power curve, which, may well be a long way from what your unshaded panels are now producing, not only can this cause some of your low output, it may cause a fault code too.

SMA inverters for example, have a setting called optitrac, which if enabled checks a wide range of input power curves to find the correct one for optimum output, some other makes of inverters have similar systems too.

As I have put before, all of your problems can be rectified, it is just a shame that you choose the company that you did to install your system.

Have you contacted them yet? If so what reply have they given you?
 
Not contacted installer yet as the manager is away this week but I have an email drafted.

Flex from the inverter to ac isolator is twin and earth 2 x 4mm and 1 x 1.5mm. White cable to generation meter is 2.5mm
 
The shading you have shown in your pic is similar to mine until about 11am when I get full sun on all panels. My generation is not impacted anywhere nearly as severe as yours. I have a sma3600 twin inverter which uses optitrac for shading issues.

I would certainly be getting the installer back if poss to see if they can be shifted along out of the shade or ask him to change the inverter. Your system as it stands would probably generate more if you removed the 2 shaded panels altogether ( I know thats not the point as you have paid good money for them).
 
provr6 said:
Your system as it stands would probably generate more if you removed the 2 shaded panels altogether ( I know thats not the point as you have paid good money for them).
Click to expand...

Or if they fitted optimisers at least the panels in sun would be able to generate at full power without being held back by a wee bit of shade.
 
davey_b said:
Or if they fitted optimisers at least the panels in sun would be able to generate at full power without being held back by a wee bit of shade.
Click to expand...

Quite possibly. They are new to me and guess they are a bit like micro inverters. I'm interested in these myself. Are they fitted to just panels that are shaded or to all panels?

Are we talking a lot of money to install to say just 2 panels. Could be a good option if not too expensive.
 
Good optimisers (SolarEdge) work down to about 5V input from the panel. ALL microinverters have a fairly narrow range of acceptable input voltage, on an average 30V poly panel, every micro-inverter available in the UK will drop below their minimum input voltage as soon as one bypass diode kicks in - voltage now down to 20V, the micro-inverter shuts down, consider two diodes now down to 10V, higher voltage output mono panels, then some micro-inverters (notable Power-One) will cope with one diode kicking in.

Net effect, micro-inverters could well be less effective than a well designed string system - e.g. SMA's optitrac.

Optimisers e.g. Solar Edge which can easily be retro-fitted to an existing inverter - they have one specifically for these purposes (I can't comment on Tigo, excpet that their voltage range is much lower than the SolarEdge) should therefore give a better output than a micro-inverter installation.

You have to fit an optimiser to each panel and they also need a central controller that sits between them and the the inverter. The central controller can them link up to on-line monitoring that can give you panel by panel output information. (Yes I know some of the panels are shaded hence the lowere outputs :) )
20130612-233901_Chart.jpg

p.s. there are 4 different makes of panel in the above set up with SolarEdge optimisers.
 

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