Compare technical specs of PV panels and inverter

NacNac

Hi everyone.

I am not sure if moneysavingexpert is the right place to talk about technical specification of solar panel. So far this is the only active forum I have found and already found many useful information. So maybe it is right to ask here.

I got a quotation for a company to install PV on the roof

I am trying to find out what type of quality of equipment they provide.

First they told me that while the panels are important, it is as critical to invest in a very good inverter so that the conversion DC to AC is of highest efficiency. In other words, if you have extra pounds to spend, better spend it on the inverter rather than the panels,

Regarding the panels

They are from Ahead Renewable Energy Ldt.
Monocrystalline Cells
3 buzz bars to increase generation in low light conditions (I was told most panels are 2 buzz bars)
6 bypass diodes to limite effect of sharing and cloud cover

Are there panels with more buzz bars and more bypass diodes ?

They also added that it is black back sheet and 50mm black frames,
10y product guarantee, 90% performance guarantee after 12years and 85% performance guarantee after 25years

And of course they completed by adding that Ahead modules outperform 99% of its competitors on PV. Is that true ??


On the inverter
2 MPPT. 99,9% efficient tracking accuracy for dual roofs and macimum generation in cloudy conditions. 96,2% max efficiency which means more transportation power
It has a built in Wi-Fi to monitor and fully understand the generation through a webpage. It is IP65rating and warranty is 10y and can be extended to 25y. Also it support batteries, if I want to add battery in the future.


Where can I found information about what criteria are important, what they mean, how can I compare the products.

What is the opinion of the experts ?

Thank you
Best regards

tunnel

Might be an idea if you actually stated the make and model of the panels and inverter rather than just giving the statistics.


What returns have you been offered on the install(total annual generation), where are you?(roughly), which direction does your roof point...N,S,E or West? Pitch of the roof? Cost of install?


No-one can give you any idea of the best kit for your circumstances without this information.


And of course, the company will tell you that theirs is the best system, what sort of a sales team would they be if they didn't?


You may be better getting some other quotes too, don't take the word of the first company that you get in, we've seen it so many times before.......big mistakes have been made!!!

NacNac

Hi Tunnel,
thank you for your reply

I agree, one quotation is not enough, but one must always start with one


The panels are from Ahead, a UK PV manufacturer.
I do not have the model number but Ahead website list 2 (aheadrenewableenergy dot co dot uk

The Inverter is Omnic
I do not have more information than already specified at the moment
The orientation of the roof is South in Cheshire. Pitch of the roof, between 35 and 40°

The cost of the installation proposed is not relevant to this post as I am seeking to understand what make a panel and inverter more performing than an another. Is a 3 buzz bars better than a 2 but not as good than a 4 buzz bars (assuming 4 buzz bars exist). why 6 bypass diodes, why not more ? etc....

As said, this may not be the right forum as it is about Saving Money here but I did not know where to start. If someone knows a website that will explain the technical aspect of a solar panel and inverter, I would like to know it. I could not find any.

I hope I have clarify the reason why I have created this post.

Thank you and best regards

Martyn1981

Hiya NacNac.

Found those panels on an on-line shop, they seem a bit expensive. But could have just been where I was looking.

That inverter range seems quite cheap, efficiency fine, but nothing to write home about.

As to which/what are best, come back in 10 years and let us know how it went, though I'm not sure how you'll be able to compare performance (to what?).

Appreciate that you wanted expert opinions, but again, what'll they be comparing against (at this stage), and will anyone be willing to stick their necks out.

Folk on here will be more than happy to chat about 'the package', kWp, cost orientation etc. What sort of generation you could expect, whether the salesman's figures are reasonable etc etc. But if that's not (yet) relevant, tricky to say much more.

You could try the electricians forum for advice I suppose.

Mart.

PS What do the buzz bars do? M.

mac2008

As usual Martyn has some good advice.


I assume by buzz bars you mean busbars? It is not obvious to me why 3 would be better than 2 if the module is properly designed. Busbars are just bits of metal that conduct electricity. I guess more and/or larger ones might reduce losses and therefore make the panel more efficient, but surely the long runs of cable from the panels and then from inverter to consumer unit would have more of an effect? If someone can tell me otherwise though then fine.


As Martyn says the inverter efficiency is OK and built in monitoring is useful as for me at least having the generation so visible means I think about ways of using it! Inverter efficiency should in theory be easy to compare using the 'euro efficiency' figure you should find on the spec sheets of most inverters.


It would be useful to start with the basics though - how many kWh per year are the company claiming you will generate and have they given you a payback period or yearly total savings/income figure?

NacNac

Hello everyone,

thank you all for your contribution. As you say, this forum is more interested in the financial aspects than the technical one. That is perfectly fine. just me not been able to find another place to talk more about the technical specs.

At the moment I am less interested in the financial and return aspect but here is what I have from , so far , the only quote I have.

16 panels 250w so a 4kWp system.
(orientation of the PC system degrees from South 10°, inclination of the system, degree from horizontal 30°

kWh/kWp (Kk) from table 857 , shade factor 0, estimate annual output (kWp*Kk*SF = 3728 kWh

Installed system size 4kWp, estimated annual system output using standard MCS standards 857kWh

FIT, 0,1438 * 3428 = 492,95
Exported to grid 50% 1714 * 0,477 export tariff = 81,76
Electricity saving 50% 1714 * 0,15p per kWh = 257,10
Total benefit first year estimated at 492,95 + 81,76 + 257,10 = 831,80


Fully installed cost 6750
payback 8,11year

They also mentioned iboost for 500pounds extra.


as for buzz bar, it seems, after a few research that it is the same than busbar.

I also just found a website call solarpaneltalk dot com

I'll try to get my technical information from there.

Thanks all for your time and feedback. much appreciated

tunnel

Hi NacNac,

As for your quote, basically, its too expensive. You should be able to get the same sort of set-up(specwise) for sub £6k which would include the iboost, the returns don't look too bad apart from the deemed electric savings, its usual for companies to quote 50% usage when in actual fact, without any add ons(iboost) or any sort of monitoring to utilise when your generating the most, that figure is just pie in the sky and probably closer to 25%

I appreciate you want to know the technical information and for that you may need to look elsewhere, maybe try here http://www.navitron.org.uk/forum/
i'm led to believe there's installers that post on there that may be better equipped to answer your questions

ed110220

I think the trouble with solar panels is that there are a huge number of models and they are difficult to compare because the average user only has one type. That's especially so for the standard panels around 250 W that you're looking at. If you're looking at the panels with some unique selling point such as higher efficiency (so you can get the same wattage in a smaller area, with say 300 or 330 W panels) then it gets a bit simpler as there are far fewer of them, so they tend to be better known. But it seems you have enough roof room so don't need to go down that route unless you can and want to go over 4 kW (say 5 kW from 16x 330 W panels).

Photon Info in Germany have been doing a field test of panels near Aachen to measure actual performance. The conditions should be broadly comparable with southern England I guess. 2012 seems to be the last year they have full results (something seems to have gone wrong for 2013). Basically the best performing panel generated 17% more per kW of panel than the worst.

http://www.solar360.com.au/files/YINGLI%20YGE%20Photon%20Module%20Yield%20Test%202012.pdf

Ed

nigelpm

Technical specs for vanity.

Financial aspects for dough!