I am a new PV householder - advice please. Unbalanced strings and wrong inverter

[juniperz]

they will have to change the startup voltage on the inverter for the string of 4 but still a result for you.

I think they are going to do 6 + 10 (so that must be 4 at 35% + 2 at 30% on one string, and 10 at 30% on the other).

 

[babba]

I think they are going to do 6 + 10 (so that must be 4 at 35% + 2 at 30% on one string, and 10 at 30% on the other).

Is the garage attached to the house and overshaded, can you tell us the name of the installer so people can avoid them.
Some people blame the MCS for rubbish installs but you know wrong from right and you still want this. ???

 

[juniperz]

Is the garage attached to the house and overshaded, can you tell us the name of the installer so people can avoid them.
Some people blame the MCS for rubbish installs but you know wrong from right and you still want this. ???

No shading.
I don't really want to name and shame, especially while the work is still outstanding (I don't mean that their work is outstanding!!).
It is a dilemma.

• I want solar and the current FIT.
• I signed a contract.
• They may have breached it, but they have complied with all my requests (agreeing to fit the quoted Growatt, fire retardant board, labelling, configuration) and due to lack of supply, I am not getting what appears to be a superior inverter (Power One) for no change in price.
• I have a house covered in scaffolding that they paid for, brackets on the roof, panels in the garage, inverter in the attic, AC cables to the utility room, a meter fitted ("generation"? I am forgetting my jargon already). I don't think I could get out of the contract, get the hardware satisfactorily removed, scaffolding down, quotes and a new contractor engaged, scaffolding up, installation and paperwork done, before 1st August.

Or am I just being a bit pessimistic?? Install completion date is now Monday 16th July by the way, which is giving me grieve at work because (not surprisingly) my wife wants me to be around!

 

[Worcester]

Make sure you keep a retention (say 10%) to cover possible snagging (sounds likely to be needed to me!), they are not allowed to withhold your MCS certificate simply because you haven't paid in full (see REAL).

Also get a completion date from them and get your Good Energy FIT application prefilled in as much as you can, http://bit.ly/Good_Energy, also give Good Energy a call (01249 766090 ) and work out your best way to get the application to them before the end of the 31st July.

 

[Eco Deal]

Missed a theard about solar edge dam it !!!! to busy moving house NO interweb at home !!!!

solar edge it !!!

 

[juniperz]

Make sure you keep a retention (say 10%) to cover possible snagging (sounds likely to be needed to me!), they are not allowed to withhold your MCS certificate simply because you haven't paid in full (see REAL).

Also get a completion date from them and get your Good Energy FIT application prefilled in as much as you can, http://bit.ly/Good_Energy, also give Good Energy a call (01249 766090 ) and work out your best way to get the application to them before the end of the 31st July.

Wow - that's a whole new set of information I didn't know about! (haven't followed link yet). I have already filled in as much as I can of a form for EDF - is this in addition?

Missed a theard about solar edge dam it !!!! to busy moving house NO interweb at home !!!!

solar edge it !!!

They wanted more than 10% of contract price to do Solar Edge (inverters must be about the same price, but you need 16 optimisers), which seemeed like a lot more than the benefit (if it can be quantified accurately). And if I said I wanted to do that today, they would have to source the parts, and I would lose my installation date (Monday 16/7). And my wife would kill me for spending even more money!

 

[Worcester]

See the thread 'Best FIT Provider' http://www.electriciansforums.net/p...een-energy-forum/59966-best-fit-provider.html it is INSTEAD of EDF.

At least with Good Energy you can actually talk to someone! They don't have a 6 week backlog, they respond to queries, they came #1 for customer service.

 

[juniperz]

See the thread 'Best FIT Provider' http://www.electriciansforums.net/p...een-energy-forum/59966-best-fit-provider.html it is INSTEAD of EDF.

At least with Good Energy you can actually talk to someone! They don't have a 6 week backlog, they respond to queries, they came #1 for customer service.

OK, thanks. So they would also become my electricity provider, it's a switch. All feels a bit late in the day and yet another thing to go wrong!

Edit: Dur - obviously, you wouldn't have one firm for FIT and another for buying electricity after dark...

 

[Earthstore]

You can choose your FIT provider, it does not have to be the same as your energy provider.
You can use Good energy as your energy provider if you choose, but my advise would be get the FIT sorted first, keep it simple.

I have posted many times that I recommend Good Energy for FIT's, and most of my customers have used them.

I hope this helps.

 

[babba]

Make sure you keep a retention (say 10%) to cover possible snagging (sounds likely to be needed to me!), they are not allowed to withhold your MCS certificate simply because you haven't paid in full (see REAL).

But they can withhold the final invoice

 

[Worcester]

Your FIT agreement is a completely seperate agreement from your electricty supplier there is no need to switch.


So long as juniperz has got the copy of the contract or the installers commissioning certificate, that will do, all he has to prove is right to ownership, the final invoice is not the only acceptable document (even though it is often the one people use) hence the reason to give the FIT provider a call and find out what is acceptable.

 

[Noshocks]

Your FIT agreement is a completely seperate agreement from your electricty supplier there is no need to switch.


So long as juniperz has got the copy of the contract or the installers commissioning certificate, that will do, all he has to prove is right to ownership, the final invoice is not the only acceptable document (even though it is often the one people use) hence the reason to give the FIT provider a call and find out what is acceptable.

Electricity suppliers have contacted me quite a few times to check the customers has paid the invoice, its the words they always use, sometimes i forgot to stamp paid on the invoice and they have always phoned me to check, so right or wrong they want proof that the customer has paid for the system in full.

 

[provr6]

I think they are going to do 6 + 10 (so that must be 4 at 35% + 2 at 30% on one string, and 10 at 30% on the other).

Am I correct in saying they are changing from 4 + 12 to 6 + 10 but only 4 panels are actually sited on the garage roof and the other 2 in the string on the main house? Apart from the different inclinations 30 & 35 degrees i think i read (which shouldn't cause a problem) are the roofs at different heights because this could impact on the efficiency?

You seem to have benefitted with Power 0ne inverter I would agree. Funny enough I was quoted on one and the installer substituted it without telling me to an SMA 3600 TL. I looked up some reviews and felt it was comparable so didn't kick up a fuss.

Apart from the documents required by your FIT provider, two things I would check from my own experience, is one that he has notified building control (who will come out and check its being installed correctly (if you ask them to) and issue a Part P cert) and two make sure he has notified the DNO of the installation and ask for a copy of the G83 notification. He has upto 28 days after the installation to submit the notification.

 

[provr6]

You can choose your FIT provider, it does not have to be the same as your energy provider.
You can use Good energy as your energy provider if you choose, but my advise would be get the FIT sorted first, keep it simple.

I have posted many times that I recommend Good Energy for FIT's, and most of my customers have used them.

I hope this helps.

Do you not think there is some leverage in having your elec supplier as your FIT supplier? If there are problems in getting paid you have got some money you can withhold also. I would also like to think they would be keen to remedy any problems quickly so as not to lose your custom.

In any event, I think you can change FIT suppliers but don't quote me on that.

 

[Worcester]

Don't see any advantage at all of having them the same.

Yes you can change FIT provider, in fact the standard FIT application from Good Energy includes a section for that if that is what you are doing.

Simples

 

[provr6]

No shading.
I don't really want to name and shame, especially while the work is still outstanding (I don't mean that their work is outstanding!!).
It is a dilemma.

• I want solar and the current FIT.
• I signed a contract.
• They may have breached it, but they have complied with all my requests (agreeing to fit the quoted Growatt, fire retardant board, labelling, configuration) and due to lack of supply, I am not getting what appears to be a superior inverter (Power One) for no change in price.
• I have a house covered in scaffolding that they paid for, brackets on the roof, panels in the garage, inverter in the attic, AC cables to the utility room, a meter fitted ("generation"? I am forgetting my jargon already). I don't think I could get out of the contract, get the hardware satisfactorily removed, scaffolding down, quotes and a new contractor engaged, scaffolding up, installation and paperwork done, before 1st August.

Or am I just being a bit pessimistic?? Install completion date is now Monday 16th July by the way, which is giving me grieve at work because (not surprisingly) my wife wants me to be around!

They are acting on your concerns and remedying any breaches. I would not change horses now, get it registered for the FIT and sort out any problems afterwards. Don't let them take down the scaffolding till you are happy. Building control will make sure they are installing the brackets etc and weathering to building regs etc.

The retention is a good idea but you won't be able to do it because then the installer will not issue you with a payment in full receipt which you need for the FIT application. You are ok for time at the moment. Just make sure you email/fax your FIT application and send it special delivery and check for the signature online.

 

[Worcester]

See above, you do NOT need a payment in full receipt for your FIT application. from Good Energy's FIT application form

Proof of ownership (copy of installer’s invoice or sale agreement).

So a copy of the contract is just fine .. (p.s. contract law is one of my specialisms)

The FIT application, merely requires proof if ownership, with our commercial systems, our standard contracts allow our clients a retention amount. Standard practcie in the construction industry.

Before you release payment in full provr6's idea of getting building control in is a good idea, however the danger is that if it doesn't comply, then the MCS Certificate is not valid, and as such your FIT application won't be valid.

 

[provr6]

See above, you do NOT need a payment in full receipt for your FIT application. from Good Energy's FIT application form

So a copy of the contract is just fine .. (p.s. contract law is one of my specialisms)

The FIT application, merely requires proof if ownership, with our commercial systems, our standard contracts allow our clients a retention amount. Standard practcie in the construction industry.

Before you release payment in full provr6's idea of getting building control in is a good idea, however the danger is that if it doesn't comply, then the MCS Certificate is not valid, and as such your FIT application won't be valid.

I agree with you on the wording on ownership and an invoice should suffice. The problem can arise if a particular FIT provider dosen't understand the requirement and insists on a receipt to show payment has been made (mine did but I called them first). I would say that SSE was very good and said that any errors could be corrected without affecting the eligibity date once they received the docs.

A fair point about Building Control, and only you can make that call. The main thing they will be concerned with is the fixings to the rafters/noggins and the weathertightness. The last thing you want to have to change is the fixings because everything has to come off.

I dont think Building control will care at all about the MCS cert or the FIT application - not their remit

 

[Eco Deal]

Most fits providers WILL ask for a invoice (stamp or in pdf format) stating the customer has paid in full.

To me you have a big problem here as the installer must give you the mcs cert but they can not issue you with a paid in full invoice because your holding ten percent back.

I like to ask the other installers here would you issue an paid in full invoice if a customer told you they going to hold back 10 percent ???

If I was you I resolve issue quickly or if you think you have been mis-sold the if the installer can not resolve the problem then the real should be first port of call .

Id point them to this forum just so they know your seeking other installers advice then maybe name and shame as its not fair if somebody else follows in your foot steps.


This is what i hate about this industry the dis-honest installers who sell a load of rubbish and dont know the bums from the elbows and know nothing about designing or installing a pv system .

 

[Earthstore]

Sorry, but why would you want to hold back 10% of payment?
If you did not agree that at the signing of the contract then you probably can not legally do that now, the contract is what you both agree to.
Personally I think that is a bad idea, and it may well delay things for you, which time is not really on your side.

Building regulations, there is and has been so much confusion over this, and over the last 2 years I have gone into great detail with my local building control to try and clarify the situation, following my last conversation with them after they had received new guidance you do not need building regs, although it may be a good idea, they check for Part P (electrical certificate) Part C (water ingress) and structural loadings (which you should have calculations for.)

So what you should have from your installer is structural calculations (you need proof that your roof is strong enough) wind loading calculations, and a copy of their Part P certificate.

None of this will effect your FIT application, or will it effect how the system works, it may cause problems in the future if you decide to sell your property and a surveyor/solicitor asks for these documents.

Building regs in my area costs just over £100, it may be worth it for peace of mind, and they may pick up something that is not correct, however, they are not PV experts, just inspectors with limited training and ever changing guidance.

Just get on and have it installed, I am sure it will all be fine, you can post pics on here after, there are many that will find fault if there is any.

I hope this helps.

 

[juniperz]

Well the installation was completed yesterday.
I have the Power One PVI 3.6-OUTD-16A mounted on fire retardant board, with isolators labelled properly, and the 16x Suntech STP 245S 20Wd wired as 6+10. There is a wiring schematic (showing 6+10) in the cupboard next to the generation meter in the utility room, and a Wattson Solar meter (provided) quietly glowing. When I was home yesterday (wet and miserable), I didn't see it go above 600W, but my wife allegedly saw over 3000W today.

I guess I should be happy, but there is a bit of a sour taste because it took such a lot of effort...

Thank you all for your help - I don't know quite how I would have got to this conclusion without you. What did we do before t'Internet?

I took a few pictures yesterday, while the scaffolding was still up.

House​

Garage​

Comments welcome...
When I am home again on Thursday, I will take some internal shots too.
I will also see what the peak output has been from the inverter display, and what the startup voltage for the string of 6 has been set to. Power-One String Tool says it should be 185V, if I have interpreted that correctly.
Following recommendations here, we are going to go with Good Energy as the FIT provider.

 

[wstevew]

Are the cables not tied up off of the roof?

 

[cbw]

That is SOOO much better!

 

[sedgy34]

So you got there in the end!!! Also the configuration of strings and the inverter choice of modules are all good, looks like they have earthed the arrays as your earthing arrangment is pme.
Just thinking back to what they proposed to install makes me smile considering the effort all on here spent giving you the good advice you needed.
Happy result! Now watch them cheques come through your door lol we just need a bit of sunshine we can't help with that lol

 

[juniperz]

Are the cables not tied up off of the roof?

I am not sure how to respond to this. Presumably you think the answer is no, and that this is a bad thing?

 

[juniperz]

I am very familiar with both Growatt and Samil.
Growatt3600MTL has DUAL Trackers. It is much more better than Samil's 4400TL because some main reasons
1) Growatt has dual trackers, fit perfectly to two-direction-roofs. Samil 4400 only 1 tracker
2) Growatt3600MTL's cap current is 16A, G83, which means fast installation without application from DNO in advance
While Samil 4400TL looks like G59 certified, it needs 8 weeks for application of installation
3) 3600w is much more suitable for your request. 4400 doesn't match your panel design
I do think the Dual-Tracker 3600MTL is worthy to use.

I think you might have skipped a few posts ;-) (It did turn into a rather long thread!)
They quoted Growatt, erroneously fitted Samil but I cried "Foul" and finally got the Power One PVI 3.6-OUTD-16A, which also has dual MPPTs. The consensus seems to be that I got the best* inverter in the end.

* and before someone points it out, Solar Edge would have been the best but I tried hard for that, but wasn't prepared to pay an extra 10% of contract price and risk further delay.

 

[juniperz]

So you got there in the end!!! Also the configuration of strings and the inverter choice of modules are all good, looks like they have earthed the arrays as your earthing arrangment is pme.
Just thinking back to what they proposed to install makes me smile considering the effort all on here spent giving you the good advice you needed.
Happy result! Now watch them cheques come through your door lol we just need a bit of sunshine we can't help with that lol

I am afraid to say that me wanting solar seems to have triggered the most sun-less summer imaginable!!

 

[provr6]

I am not sure how to respond to this. Presumably you think the answer is no, and that this is a bad thing?

Can't tell from the pics, but its a good idea to have the cables under the panels cable tied so they don't blow in the wind, scrape along the roof and over time wear away. You can sometimes hear them in high winds, which can be annoying. It's worth doing as it only takes 5 mins.

All looks good to me, I see that 2 of the 6 panels are on the main roof with the other 4 on the garage. It dosen't look that much higher and looks to be about the same pitch so should be fine.

Get your fit application in now and check they have received it and its correct. You've still got plenty of time to make any corrections if need be. Well done.

 

[jason121]

tiles have not have cut or is it me seeing things

They need to go out and buy a bending spring ruff conduit work

 

[MickF]

It LOOKS quite smart, however, my Snagging List would include:
Cable Entry Weatherproof (Photo 12)
Cable Entry protected from chaffing (Photo 12)
Cables secured / tied to rails / not dangling on roof (photo 9)
Make sure gaps under tiles aren't too great / grind backs of tiles if nescessary to make them sit flush so that water won't ingress under them. (photo 5, house, not acceptable)

Use a hole cutter to put conduit through eaves (photo 5)
Conduit labelled (DC Cables) ...
Conduit secured - The could have brought it out further along the eaves or taken it along the wall and secured conduit to rail on Garage Roof (photo 3 / 4)
Clamps should be on the 1/4 points of the panels +- 1/8th (photo 9) - Also applies to house to some degree.


What does the inverter, cu, isolator and meter installation look like?

 

[MickF]

aha I see the problem on the position of the clamps - they have vertical rails, but not in a cross rail configuration, they've just got vertical rails, so no chance to position them properly

 

[sedgy34]

your a mean bunch lol:smilewinkgrin:

 

[juniperz]

aha I see the problem on the position of the clamps - they have vertical rails, but not in a cross rail configuration, they've just got vertical rails, so no chance to position them properly

Thanks Mick. Not sure I understand that bit though.
Does it relate to grinding the backs of the tiles? Or to "Clamps should be on the 1/4 points of the panels +- 1/8th"?

I work away, but I will post pictures of the inverter, cu, isolator and meter installation when I am back home Thursday night.

 

[MickF]

It related to the position of the clamps on the panels (usually 1/4 point +- 1/8th so 1/8th - 3/8th = 1 1/4 cells through 3 3/4 cells)

Best practice for landscape is to mount rails horizontally as normal and then put another set of rails across them (cross rail) that way you are not restricted by where the rafters are and so you can get the supporting (vertical) rails in the right position. If you can get the vertical rails to line up with where they should be without doing it that way - you're very lucky - especially with 4 panels in a line. Of course to do it that way costs more with twice as much rail, plus the cross rail brackets.

I wouldn't have commented on it with just the main roof, they are probably just about ok without measuring. The garage roof is well out of normal range - the panels should have mounting instructions which specify the acceptable clamp positions. There are only a couple of panels that allow you to clamp on the short sides, so they got a bit of it right - the prinicpal, just screwed up on the practice part.

What is scary is just how many installations have been probably been done like this, at least juniperz has had the guts to ask the questions and challenge his installers - perhaps they should come and read this thread, but then again they probably think they don't need to.

 

[juniperz]

your a mean bunch lol:smilewinkgrin:

I can't quite decide whether I want to know about the bad things. I don't think these things are show-stoppers, unlike fitting the wrong inverter and arguably not mounting on fire retardant board.
After all the grief I have given the installer, I am not sure how receptive they will be to this feedback, especially as the scaffolding may be coming down today - I haven't been at home since Monday.

 

[Somecamel]

Not to rock the boat here at all but on the smaller string (6 Panels) did they reduce the startup voltage to 185v?

 

[MickF]

Better to keep the boat rocking now, that will save them the expense of putting up the scaffolding again in a couple of weeks.

When the wires chaff through in a couple of years / the roof leaks in the next big downpour, and they have gone out of business. Who is going to pay for it then?

These faults are actually just as, if not more important than the string / inverter combination.

They will not be able to sign off the commissioning certificate or issue a buidling regs certificate with the way it is.

 

[juniperz]

Not to rock the boat here at all but on the smaller string (6 Panels) did they reduce the startup voltage to 185v?

I may be a complete amateur, but I did say above, that I would check that when I get home. It's almost as if I know what I am talking about! Thanks to you contributors.
Will have a think about the building related concerns when I have a chance - busy day.

 

[MickF]

Well done juniperz, I think it's incredible that you are able to keep your cool with all that's been going on

 

[sedgy34]

Thanks Mick. Not sure I understand that bit though.
Does it relate to grinding the backs of the tiles? Or to "Clamps should be on the 1/4 points of the panels +- 1/8th"?

I work away, but I will post pictures of the inverter, cu, isolator and meter installation when I am back home Thursday night.

You could have posted the best installation in the world and still have op pickin faults with it!

 

[provr6]

Not to rock the boat here at all but on the smaller string (6 Panels) did they reduce the startup voltage to 185v?

What's is the calculation to determine the min'm start up? I think it's something to do with one of the voltage specs on the panel x the No. of panels.

Is it detrimental to lower the start up voltage to the inverters min'm start up voltage in all situations?

 

[juniperz]

Better to keep the boat rocking now, that will save them the expense of putting up the scaffolding again in a couple of weeks.

When the wires chaff through in a couple of years / the roof leaks in the next big downpour, and they have gone out of business. Who is going to pay for it then?

These faults are actually just as, if not more important than the string / inverter combination.

They will not be able to sign off the commissioning certificate or issue a buidling regs certificate with the way it is.

What does the last sentence mean? I believe that the installer has to notify Building Control within a month or so, but if they think they have done a satisfactory job, what is to stop them just completing the two certificates you mention? Will Building Control come and check?

 

[MickF]

I reckon it would be possible to visit any install any body chooses and find soemthing that could have been done better with it.

However if someone says 'what do you see wrong with this?' it would be wrong not to give them your opinion, up to them then what they do about it. At least most of those items are fairly easily fixable.

And all credit to juniperz to act on the advice he's been given.

 

[MickF]

What does the last sentence mean? They are making declarations that everything this is right, so they shouldn't

I believe that the installer has to notify Building Control within a month or so, but if they think they have done a satisfactory job, what is to stop them just completing the two certificates you mention?
Nothing at all

Will Building Control come and check? They won't unless someone asks them to

​

 

[provr6]

What does the last sentence mean? I believe that the installer has to notify Building Control within a month or so, but if they think they have done a satisfactory job, what is to stop them just completing the two certificates you mention? Will Building Control come and check?

I think the previous post is a bit misleading (not mickf's but the one above your quote). They will be able to sign it off and commission it even if it's wrong (in their eyes its not wrong).

In terms of notifying building control within a month or so, I think you are referring to the Part P certificate. They have to issue their certficates within 28 days of comissioning (date on the mcs certificate) to Building control who will then issue a Part P certificate either directly to you or to your installer (some installers will ask for this to come to them and only release when paid in full).

This won't affect your fit registration. Strictly speaking Building control shoud be notified before the work started (not for Part P but to check the installation was being done to building regs - Don't worry too much though). Building control won't be interested in coming out and will issue the part P without looking at your install (unless you ask them to).

 

[Somecamel]

What's is the calculation to determine the min'm start up? I think it's something to do with one of the voltage specs on the panel x the No. of panels.

Is it detrimental to lower the start up voltage to the inverters min'm start up voltage in all situations?

Better still use this Power-One String Tool

 

[juniperz]

Better still use this Power-One String Tool

That's what I said at the top of page 7. And did ;-)

 

[Somecamel]

That's what I said at the top of page 7. And did ;-)

My bad, I need to learn to read

 

[juniperz]

And all credit to juniperz to act on the advice he's been given.

I have just hit 50 posts in a Solar sub-forum - I think I need to get out more!

 

[juniperz]

I think the previous post is a bit misleading (not mickf's but the one above your quote). They will be able to sign it off and commission it even if it's wrong (in their eyes its not wrong).

In terms of notifying building control within a month or so, I think you are referring to the Part P certificate. They have to issue their certficates within 28 days of comissioning (date on the mcs certificate) to Building control who will then issue a Part P certificate either directly to you or to your installer (some installers will ask for this to come to them and only release when paid in full).

This won't affect your fit registration. Strictly speaking Building control shoud be notified before the work started (not for Part P but to check the installation was being done to building regs - Don't worry too much though). Building control won't be interested in coming out and will issue the part P without looking at your install (unless you ask them to).

I just had a chat with one of the inspectors from Building Control. He didn't seem too concerned about the risk of water ingress from the brackets lifting the tiles, or brackets or untied cables. Certainly didn't think a visit was necessary, though also suggested that if the installer is in a "compentent persons scheme" they could self certify for structure and weather proofing, and he had no jurisdiction. No idea whether my installer is in such a scheme, though they are quite a large firm, so maybe they are.

I think I am on the verge of giving up the fight and getting on with my life...