Help with picking a solar solution

n3ilb3 · Dec 1, 2014

Hi All, thanks for taking the time to read this!!

I'm currently trying to decide on a solar PV system to get installed on my house. I've a budget of £9K and whatever I don't spend on the solution will just get paid off the mortgage.

I'm limited to 16 panels/4kW. Roof faces SE and there isn't a lot of shading, i'd guess about 10% of the roof for a few hours in the morning, Oct - Feb. I'm in Northern Ireland btw.

So far I've got 4 quotes from 2 companies with a 5th on the way from another company.

Company A, offering a Solax inverter, Antaris M6 panels and a smart immersion heater - £7,600
Company A, as above with an optimiser - £9,600
Company B, offering a Fronius inverter, Q Cell Pro G3 Panels and smart immersion heater - £6,500
Company B, offering enphase micro inverters, Q Cell Pro G3 Panels and smart immersion heater - £7,500.

Key selling points for each seem to be warranty length, and quality of the panels and inverters. I can only take them at their word on this as I don't know much about what is good quality and what isn't.

Quote 2 appeals as the optimiser deals with any shading/faulty panels without impacting the whole system and the software for monitoring the system looks great, however I can't see it making the system that more efficient that it will pay for the optimiser (£2k) in less than 10 years, and probably more like 15 or 20. Quote 4 came about because company B doesn't do optimisers but using the micro inverters will let me have a similar level of monitoring.

I'm a bit lost as to which one is the best for a ROI or whether I should look at a different solution?

Any opinions on monocrystalline or polycrystalline panels? Anyone had nightmares with lots micro inverters failing?

Thanks for the help!

Neil

whinmoor · Dec 1, 2014

Ok - I'll have a go at this...bearing in mind I don't know anything about the market in N.I.

I would base my decision less on the actual kit being offered and more on the installation company that's going to be doing some major surgery on my house. Decent installers don't want to be associated with the cheap tacky stuff that's available at the lower end of the market. I would want to know a bit about their background and check out their credentials. How did the surveys go? Did the surveyor/salesman know what he was talking about? Was he thorough and did he fill you with confidence? Did you get the clear quotations and do you feel the figures have been fiddled?

If 10% of the roof will be shaded in winter, might it be possible to install 12, 13, 14 or 15 more powerful panels to position the panels differently to avoid the shade?

It seems to me difficult to justify the extra outlay on micro-inverters/optimisers on economic grounds. You also have the additional risk of extra components on the roof which could fail. On the other hand, the panel-level monitoring offered by Enphase and Solar Edge is pretty cool but is it worth so much extra to you?

In short, I wouldn't go for any of the four options listed. If I really had to, I'd ask for Option 3 with a different inverter such as an ABB Power One but using fewer panels to avoid the shaded area.

n3ilb3 · Dec 2, 2014

Thanks whinmoor, that's food for thought!

Leesparkykent · Dec 2, 2014

I would recommend looking at solaredge

akaPABLO · Feb 17, 2015

I second solar edge

tell them they can have your contract for 5.5k that's market value and see if they walk. Spend the 3.5k on a nice holiday.

macca499 · Feb 26, 2015

Hi n3ilb3,
I haven't been on here in a while as we have been so busy but if you haven't bought your system yet we are based in NI, can beat both of the quotes above with Solarworld or LG panels and either SMA or Solaredge inverters, all work is top quality and we will have multiple jobs near you to view before you order. Another key difference is that we include structural calculations and also pay for and submit a building control application to your local council which is a legal requirement in NI. None of the 2 companies above will mention the building control as they are heavily sales focused with commission only salesmen.

Thanks,

David