Help please - 2 parallel South South East facing roofs

[jdeep]

Dont believe any of this but as I understand his explanation - They use my job as a marketing opportunity for them and their much larger Parent Company. They spend nothing on general marketing but target around every successful job. This makes them more profit than 20% of my job over 5 years so they make a profit and I get my money back. However just in case it doesn't work in my case it is Insurnce backed guaranteed.
Been reading the other threads tonight and there are good guys and arses in every market. You guys have been excellent with me and I have no reason to mistrust most of the guys I have seen over the last few days. Good luck with this business long term

 

[screwdriver]

Go suntech 250 and power one pvi 3.6 inverter, dual tracker, can run unequal strings no probs and very good efficiency.

Oh and knock the chimney down!

 

[jdeep]

Cheers Screwdriver, Happy to take chimney down soon as its on its last legs

Don't know if this is the correct etiquette but

To Daytoa 600 - tried to reply to your personal message but your inbox is full

 

[jdeep]

Hi again - one last favour I promise. I have spoken to 2 suppliers and it looks like I now have 2 good options to choose from and any advice would be helpful.
1. a 4kWp 16 x 250 Suntech split over 2 roofs (11 + 5) with Aurora Power One 3.6 inverter as suggested above or
2. a 3.5kWp 14 x 250 Sanyo with the inverter of my choice to fit on the larger roof.

I believe the Sanyo system will be more expensive by around £900. Which would you choose please

 

[SolarCity]

That is a difficult question. The Suntech panels are pretty good but if you consider you will only being doing this once (hopefully), then it may be worth paying the extra and getting 14 panels on the one roof with the Sanyo system.

Both options appear pretty good though.

 

[jdeep]

Cheers Solar City. I am really tempted by the Sanyo. They seem to be the "best" panel and can all be placed on one roof at the back of the house.

Only one additional problem in my mind is that the company offering the Sanyo have only obtained their MCS certification in Nov last year. The started the company up in July 2011 and previously worked for other companies for years before. They are in REAL and MCS accredited and seem very genuine.
My head tells me to play safe with the Suntech unless the Sanyo is a much much better deal but am I worrying about nothing if they are MCS and in REAL.

 

[SolarCity]

The key is to talk to their past customers and go and take a look at their work.

I've seen work from MCS firms that have been registered for ages that is utterly shocking so it's not necessarily a good measure of quality.

 

[Earthstore]

On the main roof are they leaving a decent border around the edge, it should be 500mm, or are they squeezing as many panels on as possible?
Why not go for the Suntech and have two inverters, you may find you would get more out of your system that way.
Hope this helps.

 

[jdeep]

SloarCity - I now have 3 previous customers telephone numbers to chat with tomorrow
Earthstore - We estimate 300mm from Ridge to first and the same gap from bottom panel to guttering
Following earlier advice on here I looked at power one pvi 3.6 inverter, dual tracker to run 2 uneven strings (11 + 5) or (10 + 6) or to deal with shading issues.
I believe reducing the start up voltage on MPPT 2 helps.
Happy to consider 2 smaller inverters. Do their combined ratings need to be under 4kW. Will they still be guaranteed not to produce more than 16A

 

[SolarCity]

Something to consider when going for two inverters is that the efficiency of the smaller inverters will probably be lower than if you went for a single inverter. Transformerless inverters are a rare beast when you go below 2kWp.

I'm preparing to be proven wrong with this, but I don't consider a low start up voltage to be such a big issue. It certainly helps with designing a system but you really don't need much light to get a pretty high voltage so I don't see it increasing yield much, if at all.

 

[jdeep]

Hi SolarCity and others, First sunny weekend day for ages up here, Spent most of it on garage roof watching shadows and on SunCalc website. How sad am I.
I am almost certain to to go 4kW 16 X 250 Suntech (11 + 5 split). With power one pvi 3.6 inverter. I will have no shadow on 11 but some shadow from chimney on 5 from mid afternoon. Shadow should be reduced when sun higher in sky. Need to act quickly for March deadline but look to take down chimney during summer. Unless the installers tell me differently I will leave start up voltage at default. The company originally suggested 2982 kWh on a 3.5 kWp system. Hope for around 3200 for 4 kWp.
Thanks for all your help