Solar Panel Guide Discussion

CrazyCol

Orrery + Martyn
Thanks for the advice will complete ASAP & yes the reading is going backwards too.
Why do they not insist that an export meter is fitted to enable a true reading to be obtained rather than the 50/50 assumption.
I would hope to use more than 50% but it seems harder than I thought even with the immersion heater iboost heating all our hot water.

KevinG

KevinG wrote: »

No indication that they might try to back-bill me. I've opted for polling day, 7th May, I'll let you know how it goes.

The meter exchange went ahead as planned, the man from EDF Energy (not my supplier, but they look after the meters in this area) phoned me when he was about 20 minutes away; he was friendly and efficient and I lost about 35 minutes generation (sunny throughout, unfortunately!). I've already got my dear wife on the case of using the iron when the sun is shining and such like, we'll see how it goes with the electricty bills. I have still had no indication that Scottish Power might try to back-bill me.

John_Pierpoint

zeupater wrote: »

Hi Misslayed

You should really follow the advice given by tunnel ASAP. When you registered for FiTs you should have signed a document to state whether the meter runs backwards when exporting, but your obligations do not end there - if you do not inform your supplier of the reversing meter then you're simply leaving yourself open to the possibility of the supplier issuing a corrective bill which, unless you are a meticulous record keeper, there will be little chance of appealing ...

Now, regarding inverter positioning, these would normally be in a loft, garage or utility room ... members of this very forum also have them in large cupboards, under the stairs, in the hall by the front door and even in the downstairs loo .. there's even members with them mounted outside if manufacturer's IP rating allows (http://en.wikipedia.org/wiki/IP_Code).

Without knowing what your 14 panels are, their orientation and location we'd have no idea whether the figures quoted would be considered good or bad. As a direct comparison, our ~4kWp system at almost WSW beat 4.01kWh on 10 occasions last December, with the best day being just short of 7kWh .... if you could supply details - rough location, orientation & roof angle along with total panel capacity (on your MCS certificate) then someone will provide a set of estimated monthly targets for you to measure performance against ... alternatively, plug the details into the PVGIS calculator here ... http://re.jrc.ec.europa.eu/pvgis/apps4/pvest.php

HTH
Z

EricMears wrote: »

Bear in mind also that the 'supplier' and the 'FIT paying organisation' may not be the same company (and even if they are, half the time the FIT team don't talk to the billing team ).

I can't see any reason why the suppliers shouldn't be able to sue for lost revenue for the whole six year period to which the Statute of Limitations applies - unless of course you've advised supplier that you think their meter may be unfit for purpose (and if they decide to ignore your advice they'd accept liability for any errors).

If I remember correctly "Which?" claimed the supplier could only go back 2 years, not the English normal 6 years Statute of Limitations.

Scottish Power (It reports to its Spanish bosses) is about as badly run as was the Spanish owned Gatwick airport. Fortunately I was able to migrate away after paying my considerably under estimated bills - some fiasco over reading my meter.
The only intelligent member of staff was the guy who was supposed to persuade me not to leave.

1961Nick wrote: »

The 'cap' can be clearly seen on this chart of my best ever day. If the cap were removed & the graph extrapolated, the overall generation for the day wouldn't be that much higher.

Hi Nick,

SNAP or almost exactly snap in terms of inverter roof slope orientation etc (I am 46 degrees east of due south.)
I have suffered just a little from over voltage in the local power supply, though after about 12 months of being regularly served with warnings about the local network being rejigged, I suffered a morning of power cut and now the voltage is the the range 245 - 250 according to the inverter.

My installation was on 14feb12, it cost £10k and the sole criteria was "can you get it done and registered before the March deadline."

The manufacturer and supplier of Aurora inverters has been taken over by ABB -

http://en.wikipedia.org/wiki/Brown,_Boveri_%26_Cie
http://en.wikipedia.org/wiki/ABB_Group

They are still selling these California designed and Italian manufactured (?) inverters and we should be in good hands.

I am hoping our next hurdle won't be this side of the need to replace the battery that keeps the software alive over night.

I will compare notes then.

John.

PS April was a good month for me, my generation figures:

[FONT=Times New Roman,sans-serif]April '12 thru '15 kWh monthly readings:
376 - 383 - 443 - 482 it must be climate change [/FONT]

The cool of the morning air ?.

oldskoo1

My solar install started today and hasn't finished due to some delays

However i went out to look just after they left and noticed what i thought was shading.

We are exactly south and thus was taken around 3:20pm so i'm thinking the chimney on the top right is a reflection.

I'm not sure.... but its bothering me



This is what it normally looks like around 12pm



and this is definite shading at around 8:30am




Last thing i want is to go to all this trouble and having a perfect roof but get constant reduced outputs.

I'm bothered by this and now they are fixed i'm not sure what to do.

zeupater

oldskoo1 wrote: »

My solar install started today and hasn't finished due to some delays

However i went out to look just after they left and noticed what i thought was shading.

We are exactly south and thus was taken around 3:20pm so i'm thinking the chimney on the top right is a reflection.

I'm not sure.... but its bothering me ....


.... and this is definite shading at around 8:30am




Last thing i want is to go to all this trouble and having a perfect roof but get constant reduced outputs.

I'm bothered by this and now they are fixed i'm not sure what to do.

Hi

With that roof you'll get the same shade from the chimney on the West in the late afternoon, however, looking at the length of the shadow it's clearly far less steep than the roof itself so it'll only fall onto the panels for a very short time both ends of the day, probably a matter of minutes as the sun moves to (or from) the North and the panels move out of direct sunlight .... it's not worth worrying about as any loss will be almost negligible ....

As for the picture at 3:20, if the roof is facing South there's no way that it's shading so don't worry it's just as you thought - a reflection ....

HTH
Z

oldskoo1

Phew

Thanks Z, i actually worried that what you can see in pic 1 was a permanent shade which would exist all day.

When i calmed down and went to look from a different angle it is indeed as you say a reflection which doesn't exist looking head on.

Also the panel is actually about an inch or 2 left of the chimney flashing (weatherproof stuff). So its actually a few inches from the chimney.

I think they put it so high up because we could actually install another row of 8 beneath the current install making it 6kW system if i would like that option in the future.

They needed to put it high to obviously fit in the third row and have a couple of tiles before the gutter for controlled panel run off.

I'm very glad i am not going to get any shading being so close to the chimney.

Zoomed in view

maravesi

Hello

Interesting discussions going on. Me and partner have been thinking about a solar pv system for a few months as only just bought a house. The recent announcement that the FiT is to be cut in July has made us hurry up with quotes and research. Unfortunately, our roof is quite small (6m bottom edge, 2m top edge and 4.5m height at 38degrees pitch).

We originally got a quote from IKEA for a 1.2kWp system £3,700 but we then found out that we could get a bigger system with 240/250W or higher output panels so we asked for some quotes. One came back with a load of rubbish quoting us for a 4kWp system after having been over and done an inspection.

The other was Solarlec. They talked to us about Panasonic (which is what we originally requested the quote for) and Sharp, LG and Enhance panels.

We worked out that we can fit up to 8 Panasonics on the roof but no more than 6 of the other ones and by doing a cost per W we've narrowed it down to the following three options (price based on kWp output):

6x240W HIT Panasonic = £3.22/W
7x240W HIT Panasonic = £3.03/W
8x240W HIT Panasonic = £2.93/W but overall the most expensive system at £5,600ish.
6x250W poly-Sharp = £2.75/W
6x£250 poly-Enhance = £2.63/W

We want a best value for money system. We are not fussed about the brand names, but we also don't want to install rubbishy panels which will fail and cause trouble or won't have good output just to save some money in the short run.

There is a possibility of a little bit of shading from a fully grown tree some distance away. The installer reckons that's only about 3% max. There is also a chimney which he thinks could ( result in up to 14% shading at certain times of day (chimney is on west side of roof).

Apologies for the long post, but this is a big decision and we want to make sure we have done our research before we commit to spending £'thousands.

So I would really appreciate your advice re the brand/quality/best option(value for money) of the above (and possibly anything better not listed?). Is there anyone who has had a system of the above panels for some time who has any comments?

And finally, what do you think about the prices quoted?

Many thanks!

Martyn1981

Hiya maravesi. Welcome to MSE.

I (and many others on here) are happy to chat and discuss potential systems, layouts, costs, returns etc. I could easily bore you to death with info and suggestions, but will keep this one short:-

Don't do it.

The cost for system sizes is just too high. I read the first paragraph, stopped, scribbled some numbers and thought, "would have to be 8 Panasonics with their narrower profile". As you already have quotes for that, and they are very high, we can jump straight to the conclusion:-

Don't do it.

Suggestions -
You appear to be describing one side of a hipped roof, do you have other rooves too?
Could you post some pics of your roof (rooves) to allow for suggestions.
Join Abundance and invest your money in one (or several) of their solar schemes instead!

I'm sure there is something possible, but hard to be positive at the moment based on your roof restrictions, and the resulting costs. Though I have to say that £4k seems (much) more than enough for an 8 panel Panasonic install.

Lastly, regarding FiT degressions. I usually say don't worry, and don't rush, but my head is in a little bit of a spin this year with the 3 cuts (1st Jan, 1st Apr & 1st Jul) this year, knocking 10% (cumulative) off the FiT. We may be in a perfect storm situation where folk rushing to beat each FiT reduction are causing installs to exceed the 100MWp degression point each quarter, resulting in another degression, and another rush. So, don't rush, especially given your circumstances and prices, but at the same time, try to make a decision, one way or the other.

Mart.

tunnel

I'm with Mart, reading your post you have other rooves,check them out first. Why would one installer offer a 4kWp system if only using the one roof.

You need to give more details if you want any help/suggestions

oldskoo1

Sorry for the boring pictures

My wife was surprised to see me up early on a Saturday.

After coffee and waiting for a break in clouds i took this at 8:30am

Despite the shadows suggesting the chimney should cast a shadow, i didn't appear to see anything on the panels. So i'm assuming all is ok.




And 9:30


So based on that it doesn't appear to get any shade.

I was reading last night these panels have a 6 bypass diodes, so even if it does get shade it should bypass and pass through the higher voltage from the other panels. It made me think why are micro inverters needed but i'm sure micro inverters are a lot more controlling.

So whilst it doesn't appear to be casting a shadow i wondered two things.

Any ideas what happens to the shadows with the lower autumn and winter sun? I assuming longer and more likely to cast.

Even though there is no shadow could the chimney be reducing the ambient light?


And just out of curiosity
I wondered how an array responds when there is limited solar energy morning and evening.

I looked on pvoutput for a nearby array and it was producing 1kW of power by 7am and by 8am 2kW. It was a 4kW array, so this suggests as expected there isn't enough solar energy / light at this time.

So my curiosity is, due to the lower light levels, is the entire array unshaded required to produce that 1kW of power at 7am? Or can a part shaded array still produce that 1kW, because it is capable of 4kW.

I'm trying to string it together in my head and i'm assuming two things. The lower light morning/evening means the panels probably don't get anywhere near their peak so voltage and power is lower. Due to lower voltage any shading potentially has less influence relative to peak with shading. But ultimately i can't assume that 1 half of my array at 2kW can produce the 1kW because the light levels are too low, it still needs the entire array extracted the lower amounts of solar energy.