at what cash level are west north west solar panels not completely mad?

robotrobo

esperluette wrote: »

dear mr Eric mears
I agree with you that one doesn't spend much time looking at the panels.But I m just stupidly fussy about the "looks of the house"and I suspect that I wouldn't be allowed to put them at the front even if I wanted to, as the1995 house is in a conservation area anyway ( albeit in cul de sac).
I'll listen to the small company chap carefully!
ill give the pvgis page a go but might need help!
many thanks
esperluette

I m just stupidly fussy about the "looks of the house"

Thats exactly why i wouldnt have them fitted to my bungalow, my personal feeling is they are unsightly , so im not bothered about the 7%+

esperluette

Dear martyn
very helpful thank you.
I don't want to throw money away , but I am more concerned about the future in terms of the planet,increasing electricity prices and improving 24 h storage facilities so immediate return on capital is not my driving force.So 400 a year would be great , as that's close to what I currently pay in electricity, and I might be a bit more careful as well!
silly question: do panels with higher wattages eg 300-327 have higher voltages?
I have now got another installer ( no 4) known for building eco houses locally coming who has promised to so a "proper survey" with ladders . The pitch of hipped roof on wsw looks the same to me ( I have told the next chaps I want it measured) and the panels should barely be visible for a few mns as one turns into the cul de sac drive- they face about 90 degrees away from the front road so I dont think that will be a problem.
The ( so far unconfirmed!) quote no 2 I had for 14 (10 wnw and 4 wsw ) 285 LG panels was 6 k, which was 1.2 k less than the first big boy quote of over 7k for 10 wnw benq 330.It really is a minefield out there, and thank god for for the experts on this forum!
robotrobo
I also think that its important to be happy about the looks of one's house when one comes home.Even if that "costs". But I am hoping smaller, less obtrusive and better ones will become available in the next few years, even if too late for FIT.
regards
esp

Martyn1981

esperluette wrote: »

silly question: do panels with higher wattages eg 300-327 have higher voltages?

Actually it's quite an astute question, as the hybrids (in particular) are often higher voltage.

The other ones to look for are 72 or 96 cell panels, rather than the more common 60 cell (10x6) panels. The higher cell panels are often higher voltage.

Have a look at this shop, it's a very handy reference site, as they usually have the tech/spec sheets attached to each item when you click on it.

As you are looking for a minimum working voltage, look for nominal voltage. If you were worried about exceeding an inverter's max voltage, you would look at the max/open circuit voltage.

That site also has a large selection of inverter makes, so you could have a nose at the various dual MPPT models (3 to 3.68kW will do you) and see what the minimum string voltages are, also check what the minimum MPPT voltages are, to make sure you'll get the best out of them.

BTW, all of this is really an issue/concern for your installer, but personally I think it's useful to have an idea of your options. Also useful if they suck air through their teeth and say 'it's possible but will cost you a lot more' and you reply with, but the XMake xmodel inverter is only £20 more .... etc etc.

Happy shopping, keep an eye on the clock, I've lost hours in the past, it's worse than watching silly dog videos on Youtube.

Mart.

esperluette

dear martyn
my reply didnt post so I apo;ogise if this isa duplicate.
Very useful site where I have found a smaller 1,46x 100 meter 285w panasonic panel with voltages of 50-60. its a hybrid ( whats that? ).
Which is the relevant voltage to look for?regards esp
max. power (Pmax) [W]56.8
51.1
1.11
60.3
1.20
Max. power voltage (Vmp) [V]
Max. power current (Imp) [A]
Open circuit voltage (Voc) [V]
Short circuit current (Isc) [
regards esp
Electrical data (at STC)
Temperature (NOCT) [°C]
44.0
-0.29
-0.159
1.77
Temp. coefficient of Pmax [%/°C]
Temp. coefficient of Voc [V/°C ]
Temp. coefficient of lsc [mA/°C]
Temperature characteristics
At NOCT (Normal Operating Conditions)
Max. power (Pmax) [W]
221
49.2
4.50
59.5
4.85
Max. power voltage (Vmp) [V]
Max. power current (Imp) [A]
Open circuit voltage (Voc) [V]
Short circuit current (Isc) [A]
Note: Normal Operating Cell Temp.: Air mass 1.5; Irradiance = 800W/m
2
;
Air temperature 20°C; wind speed 1 m/s
At low irradiance (20%)
Max. power (Pmax) [W]
56.8
51.1
1.11
60.3
1.20
Max. power voltage (Vmp) [V]
Max. power current (Imp) [A]
Open circuit voltage (Voc) [V]
Short circuit current (Isc) [A]
Note: Low irradiance: Air mass 1.5; Irradiance = 200W/m
2
; cell temp. = 25°C
Please consult your local dealer for more information
Fixing span must be between 600-1100mm
Max. power (Pmax) [W]
285
52.0
5.49
63.5
5.91
Voltage at Max. Power (Vmp)(V)
Current at Max. Pow
Panasonic HIT N Series 285W Black Frame Hybrid SJ40




With a solar system, your customers are making a long-term and high value investment, and the quality of the modules is of great impact. Choose a renowned brand that will give you a reliable guarantee and which you can trust. The Panasonic HIT® technology is highly efficient and produces more power per square meter than traditional products - up to 28%* more. This means that you will need fewer modules on your roof to accomplish very high performance. The N285 features a reduced module length designed specifically for the European residential and commercial rooftop markets.

Closest to 4kW
Just 14 panels to reach 3.99kWp and secure the highest FiT rate in the UK

Compact size
Best fit in portrait for small roofs

Improved shading performance
Featuring 4 shading zones instead of 3

Unique water drainage
On each corner for an improved self-cleaning

Specifications:
• Rated Power: 285W
• MCS Reference: MCS PV 0034/33
• Length: 1463mm
• Width: 1053mm
• Depth: 46mm
• Vmpp: 52V
• Impp: 5.49A
• Voc: 63.5V
• Temp. Coefficient (Mpp): -0.29%
• Clamp position on panel: Long side only
• Connector Type: MC4 MATEABLE
• Efficiency: 18.5%


Panasonic HIT N Series 285W Black Frame Hybrid SJ40

Martyn1981

Morning. Hybrid panels combine both a normal silicon panel with a thin film panel coating, to give you a bit of both. These panels are more expensive per Wp, but squeeze more Wp into a given space.

Regarding voltage, you want to look for the lower figure, usually called nominal, or Vmp.

For those panels I see the spec sheet has a low irradiation figure of 47V, so that's a handy figure. Compare that to the BenQ 285Wp panels, which are around 31V.

So the Panasonics would give you about 200V on a 4 panel string.

If you look at the specs of some inverters you'll see where the problem may arise, eg the SMA 3000TL dual tracker has a min voltage of 125-150V, and a MPP range (to track best performance) of 175V+, so the BenQ's wouldn't make it.

The Samil 3400TL has a minimum of 100-150V, and an MPPT range of 165V.

The very cheap Solis 3kW dual MPPT inverter has a min voltage of 120V and a MPP min of 100V.

As I said before, nothing to worry about too much, as your installer will need to match everything up, but probably handy for you to have some idea of what the issues are, and what the various solutions are.

Mart.

esperluette

wonderful! many thanks.I feel knowledgeable by proxy!its a little bit like the solar panel, i cant store the "energy"but ill try to use it fast!
regards esp

Martyn1981

Other options might be solar slates, try Google, or triangular panels to make the install look a little nicer for hipped rooves.

These options wouldn't be cheap, but worth a quick glance if nothing else.

Mart.