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

[juniperz]

Yes, I am doing that by email to Texas (Growatt is the manufacturer). They had suggested 8+8 before I realised that there was a roof pitch difference (picture me on a roof or two, with a protractor and a spirit level - much easier with scaffolding in situ!). The comment: "... 6 +10 as this would reduce the losses because 10 panels would not be affected by the pitch difference." actually came from Growatt, but I thought I would give the installer the chance to respond.

I do sometimes feel I am doing their job for them, and I thank you all here again, for providing me with (just) sufficient knowledge to do so.

 

[juniperz]

A new development - they have just told me that they cannot get stock of the originally quote Growat 3600MTL, and have offered "Power One Aurora PVI 3.6(16A limited), which (according to our design software) should be suitable to be wired either 4+12, 6+10 or 8+8, as this has a lower tracking voltage".

I remember someone on here suggesting Power One, so I am assuming I should say yes to this.
They send me a datasheet as PDF - I have found a link to it here.
COMMENTS APPRECIATED.

 

[jason121]

go for it beats the growatt

 

[Gary K]

Snatch his hand off for that offer.- Could be one of the most efficient inverters available

 

[jerriais]

How much is the pitch difference? I'm actually attending a Solar Edge technical conference today and would certainly say they are what you need in this case. Also I really doubt they would add 10% to the overall system cost.

Sent from my HTC Desire S using Tapatalk 2

 

[pww]

Actually this is about right. The solaredge inverter is similar in price to, say, an Aurora one. In this configuration you need 16 power optimisers which would make up most of the 10%, then you need to allow for the addtional back room work (solaredge registration etc). Still think the extra would be worth paying, but OP seems not to be convinced.

 

[juniperz]

How much is the pitch difference? I'm actually attending a Solar Edge technical conference today and would certainly say they are what you need in this case. Also I really doubt they would add 10% to the overall system cost.

Sent from my HTC Desire S using Tapatalk 2

Sorry, I have only just seen this.
"We will have 4 panels on the 35% garage roof and 12 panels on the 30%

Actually this is about right. The solaredge inverter is similar in price to, say, an Aurora one. In this configuration you need 16 power optimisers which would make up most of the 10%, then you need to allow for the addtional back room work (solaredge registration etc). Still think the extra would be worth paying, but OP seems not to be convinced.

Yes, this was their rationale - similar inverter prices plus the 16 optimisers.

 

[sedgy34]

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

 

[babba]

yes looks like the four panels might as well not be there as they not going to start up the MPPT! as stated above .

Tricky one they should of either used a Mastervolt 600 for the four panels then a single tracker inverter for the other 12.

or gone for solar edge the dip sticks !!!

Makes me laugh really does

But we like a laugh.

 

[juniperz]

But we like a laugh.

Glad I caused some amusement! (I don't mean that is an offended way).

 

[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://------/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 !!!