Discuss Please advice 16 or 12 panels to achieve close to 4 kW PV System in the Solar PV Forum | Solar Panels Forum area at ElectriciansForums.net

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L

lazyIH

Hi

First post, so please be gentle. Am about to take the plunge and have a 4 kW PV system installed on a south south east facing roof.

Am seeking advice on which of the 2 following sets of panels would give us the best return:

16 x SolarWorld Mono Black (250w) panels

or

12 x Sunpower E20 327w panels

Any and all advice welcome

Cheers

LazyIH
 
if you can fit 16 solarworld panels on the roof without it ending up in shading or any other issues, then this will always give the best returns because they will / should cost significantly less than the sunpower.

no point paying for efficiency just to have more roof tiles on show, and solarworld are every bit as quality as sunpower, if not more so on a build quality, and likely lifespan scenario.

If they're the same price then get another quote for solarworld from someone more reasonable, as they shouldn't be the same price.
 
Thank you for your responses. Have just done rough pacing out inside house, I calculate 7.8 metres, so yes this might be classed as a little roof :stooge_curly:

Aim was to get as close to 4kW as we could, yep you guys are correct the Sunpower are expensive !
 
If you have restricted roof space and value for money is paramount, have a look at the 285W JA Solar silver framed panels. Very competitive price. 14 panels will get you as near as 4kW as makes no difference. 12 is still a good sized system. Shouldn't cost anymore than 16 250w panels.

if you have your heart set on black framed panels, you will pay a premium for higher output panels.
 
Black framed panels on houses should be part of planning, silver framed panels look terrible on any roof top ( not commercial) the price of black panels such as solarWorld are cheap enough to not warrant using silver framed modules.
We install 4kw solarWorld for £6k now.
 
Black framed panels on houses should be part of planning, silver framed panels look terrible on any roof top ( not commercial) the price of black panels such as solarWorld are cheap enough to not warrant using silver framed modules.
We install 4kw solarWorld for £6k now.

OK as far as it goes but rather a simplification.

If it is the principal elevation of the property (that facing the road or the one most seen) the aesthetics of the installation are vital. In these circumstances we recommend roof integration of the system and we always use black framed panels. It is also important to go for a symmetrical layout of the panels using only one orientation. We all see absolute dog's breakfasts of installs which should be deemed a criminal offence.

What if it is not the principal elevation where the visual impact is negligible? It is then not a great issue whether the panel frame is black or silver. If the array is on the side roof of a property where it won't be seen, why pay the premium for a black framed or all black panel?

Some buildings are like a face only a mother could love, and quite frankly whether the PV array frames are black or silver won't make it any more or less attractive.

Our skill and professionalism as installers should be in providing the most appropriate system for the customer in the given location. Appropriate, also includes cost effective. Cost effective does not mean the cheapest kit on the market.

It is important for the Starter of this thread to have some handle on the relative cost of different panel options. If we start with a premium black framed panel such as LG 250W or maybe SolarWorld 250W we could index their price as 100 in terms of cost per watt. The JA 285W Silver framed panel mentioned would index at 98. The LG285W black framed panel, 125, and the LG300W black frame, 130. I don't have immediate access to information on the Sunpower 327W, but think they would index at around 150.

We have done a job this week with 12 LG300. The price premium pushed up the cost of the install. From the customer's viewpoint, it was still a cost effective option.

Remember that the panels only make up one part of the price of the install. Other costs are fixed, notably the labour content. Inverter choice is also important and one on which many have their own view.

There is considerable downward price pressure on panels at the moment. We get daily emails with offer prices well below an index price of 80 for silver framed 250W polycrystalline units, some from known manufacturers with good provenance. This will feed through to the upper end of the market.

Which would bring me back to SolarWorld. Due to their own lack of investment, they found their production facilities to be uncompetitive in a world market. Rather than deal with this they were the main complainant to the EU Commission about Chinese panels that led to the so called anti dumping legislation. The irony is they have been selling panels at less than the barrier price. Their actions are holding back the market, in the end will be ineffective and counter productive. They may be made in Europe but are no better than most Chinese made panels.

What is important for the starter of this thread, is to achieve the best possible outcome for the given expenditure. I would hope who they choose provides a realistic output prediction and an accurately calculated payback period.
 
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Thank you all for the advice given so far, plus amusing comments.

Looks like I will be going for a fourteen panel system, so am thinking panels around 285w should get within a whisker of the 4kW I am wanting. As you guys say it is a financial balancing act, trying to get the best long term gain for the right initial outlay.

thanks again
 
They may be made in Europe but are no better than most Chinese made panels.
ah, now you have a point about the politics etc, but on the quality of the panels...... sorry but I can't agree with you on the quality.

The quality of the solarworld panels is obvious as soon as you pick one up, but go to their factory and it's pretty astounding the lengths they go to to test and check everything from the cell through to the finished panel - 3 x electroluminescence testing on every panel at different stages in the process for example, with automatic testing, visual checking and the ability to pull a faulty cell out and replace it, and 98% automation, so nobody using mallets and mastic tubes to put the panels together.

They also have 8MW of solar plant feeding in to the factory, apparently made up from the B grade panels that failed the testing at the final testing stage after it's too late to fix them. Any companies that are only doing random testing, or testing at only one stage of the process are going to end up with those b grade panels going out to market with microcracks and hot spots in the cells.

I'm not easily impressed, but I was impressed.

Puts the UK manufacturers to shame really, though it is something like a billion Euro plant. good to see it running full tilt 24/7 as well.
 
Has anyone started to use Sunedison panels. They give a 25 year product warranty. Range from 275watt to 285 watt
check the terms of the warranty and who it is held with though, as it's with the UK subsidiary company only.
 
Dear Forum Members
I was considering very similar options, however, as my roof would only marginally fit 15 panels (possibly not leaving enough space on the edges) I was recommended a 12x SunPower E20 327W + Samil inverter system for just almost £6k. The price appears to be very good (although it’s an older E20 NE-WHT-D version), but this company isn’t overcharging whatsoever, regardless of what system you choose (no doubts about them). Balancing all Pros and Cons, I’m keen to pay a bit more to get SunPowers, mostly because of their warranty, a higher possibility of remaining in business over years and lower degradation over time. If I get more generation on top of that – even better. It would even slightly better work with my roof, as there is only a horizontal shading in winter early morning, hence two 2x6 strings would be better positioned – one above another, close to the top of the roof.

My question is more related to the inverter. I have no problems with Samil as I’ve read lots good about it, but I’m unsure how would they fit. Voltages seem allright, but a forum member, Gavin A, wrote here a year ago with regards to Samil that ‘there's no full scan feature’. Is there anything what should opt me to consider another inverter?
 
Thank you. The only form of shading would be there in winter's early morning, before the sun will go up and above the building across the road. It will be a horizontal shade line moving down. In late afternoon the roof will be shaded completely and rapidly an hour-two before sunset, as it is positioned 20 degrees towards SE. It is though possible that very close to the winter solstice only the top two rows will get a chance to catch some direct sunlight. Does this refer to your note in any way?

And what exactly is Samil not doing with regards to this scanning, what other inverters do? I'm just curious.
Please advice 16 or 12 panels to achieve close to 4 kW PV System {filename} | ElectriciansForums.net
 
These won't work with SP 327W, which are 96-cells; Voc=65V

Enphase M215Enphase M250Enphase C250
Primary UseResidentialResidential / CommercialCommercial
Recommended Input Powerup to 270 Wup to 300 Wup to 350 W
Max input DC Voltage48 V48 V60 V
Operating range16 V - 48 V16 V - 48 V16 V - 60 V
CEC weighted efficiency96.50%96.50%96.50%
Peak output power225 W250 W250 W
Max. units per 20A branch circuit25 @ 208/17 @24024 @ 208/16 @ 24048
Module Compatibility60-cell modules60-cell modules60- and 72-cell modules
Part numberM215-60-2LL-IG-S22/S23/S24M250-60-2LL-S22/S23/S24C250-72-2LN-S2
 

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