low output until all panels in sun

[whinmoor]

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.

 

[davey_b]

Lesmahagow, just south of Glasgow.

Cheers

 

[whinmoor]

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?

 

[rocker55]

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.

 

[pvman]

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

 

[davey_b]

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

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.

 

[pvman]

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.

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 would show shading and provide an accurate prediction on what you should generate.

Tom

 

[Earthstore]

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...

 

[davey_b]

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...

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

 

[The Solar King]

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.

 

[davey_b]

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

 

[SolarCity]

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?

 

[The Solar King]

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.

 

[SRE]

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.

 

[Earthstore]

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

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?

 

[davey_b]

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

 

[provr6]

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).

 

[davey_b]

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).

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.

 

[provr6]

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.

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.

 

[Worcester]

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 )


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