Thanks Paul and that must be good advice! I am in the final process of obtaining quotes and hope that my final decision proves to be correct!

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Paul - I am very interested in the Sanyo HIT 250E10 and I believe you are in favour of them as well. I read on here that a west country installer has been running a test rig with several makes of panel and has found that the Spanish Silken has beaten them all substantially including the Sanyo HIT 240 unit!. Do you know anything about this panel and should I pursue it? I am in Herts. and intending to install a 4KW array on a south facing -5 roof of 40 degree pitch and 2.8% shading. I am also very interested in the box of tricks for heating my water tank and maybe a Sunny Backup Set s unit

Dear Englishman

I have no experience of the Siliken panel. We do know however that the Sanyo panels perform extermely well and are the best performing panel we have installed. The "box of tricks" for heating water is a great idea - albeit expensive and I believe that there are a number of back up units coming out including one from Sunnyboy.

Frankly, in light of the impending cuts it might be prudent to order the system asap and look at the ancillaries later. I believe that they can be retro-fitted.

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Paul - I am very interested in the Sanyo HIT 250E10 and I believe you are in favour of them as well. I read on here that a west country installer has been running a test rig with several makes of panel and has found that the Spanish Silken has beaten them all substantially including the Sanyo HIT 240 unit!. Do you know anything about this panel and should I pursue it? I am in Herts. and intending to install a 4KW array on a south facing -5 roof of 40 degree pitch and 2.8% shading. I am also very interested in the box of tricks for heating my water tank and maybe a Sunny Backup Set s unit.

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I've a decent-sized south facing roof in Birmingham - but it has a Velux window right in the middle, making continuous solar panels rather difficult.  A number of slates need replacing and I'm wondering whether solar panels is the best bet, or to go for solar tiles at the same time as re-roofing.  Any thoughts - and how do solar tiles compare for price, weight etc?  Is this something most suppliers could do?

Hi John

The Velux window in the middle does not cause a problem and we have installed lots of systems around them - see http://www.eco2solar.co.uk/2111/harbury-stratford-on-avon-4/ as an example.

It is advisable to ensure that your roof is in good condition before installing solar PV so it would make sense to replace the slates at the same time.

Whilst solar tiles would appear to be the most elegant solution, the price of solar tiles is still very high; probably at least double the cost of installing conventional solar panels.

This obviously adversely affects the return that you get and the payback. Fixing the roof and then installing solar panels will probably be more cost effective.

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Hi Paul

I've a decent-sized south facing roof in Birmingham - but it has a Velux window right in the middle, making continuous solar panels rather difficult.  A number of slates need replacing and I'm wondering whether solar panels is the best bet, or to go for solar tiles at the same time as re-roofing.  Any thoughts - and how do solar tiles compare for price, weight etc?  Is this something most suppliers could do?

Best wishes

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Hi Paul. Have a look at this blog which should give you more of an idea of how you measure quality in a solar pv panel. Ideally you want it to perform as well as possible for as long as possible.

As Paul says in this blog, which type of panel that is best for you will depend on the space you have available and the amount of money you want to spend.

Also, watch out for that chimney. Hard shading can cause a problem for performance.

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Hi

What is the difference between panels manufactured in China eg Suntech and those manufactured in Germany/Japan.  I've been told the quality of the latter is better eg Sharp/Sanyo.  They have the same 'performance' guarantee. Is this correct and what do people mean by quality anyway. 

My roof is south facing on the sussex  coast no shading apart from my chimney of the SSW side of my roof. 

 Is it more a question of type of panels poly v mono v hybrid and which would be best?

thanks

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Hi cautiousblue

I've been told panel performance loss over time is less with polycystalline panels than with mono panels.  Does anyone know if there is any truth in this?  I am thinking of going for the hybrid panels as we are short on roof space and they are supposed to be more performant. However the Sanyo panel did not even make it in a recent Photon report.  I'm not sure what to make of it all

This is a difficult one to get definitive information on but there is little to suggest that poly panels degrade less than mono ones. Mono will work better in low light conditions and give at least 5% more yield.

The hybrid panels work extremely well - especially the Sanyo's - adn we are seeing this now from real feedback/data from our customers that they are outperforming the estimates. I would treat these reports with a pinch of salt; Sharp effectively ignore them and pay for their own tests.

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Hi Ruth

With that price differential it is certainly worth considering the Sanyo option seriously.

What part of the country do you live?

I do think however that you may wish to get some competitive quotes. We would provide the Sharp solution for around £11,000 and the Sanyo for about £12,000 including VAT at 5%.

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I am wanting to install Solar panels on a roof with limited area ,at 30 degree elevation facing SSE. The best I can seem to get is either a Sharp monocrystalline producing 3.43Kw and costing £12,755 or  a Sanyo HIT  producing 3.50 KW and costing £13,789. Looking at a time period of 25 years which solution is the best option? Will the claims of Sanyo to out perform a monocrystalline system  in low light or higher temperatures be sufficient to pay back the extra £1000 investment? Can anyone  give further advice?

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I've been told panel performance loss over time is less with polycystalline panels than with mono panels.  Does anyone know if there is any truth in this?  I am thinking of going for the hybrid panels as we are short on roof space and they are supposed to be more performant. However the Sanyo panel did not even make it in a recent Photon report.  I'm not sure what to make of it all

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"Thank you Paul - so if roof space is not a problem go with the cheaper Sharps. I've had 2 quotes so far one said go for the Sunny boy 3300 another the 3800. The later as it would not be running at full capacity so last longer.....

Any thoughts ?"

The Sanyo array should give you around 10% more output across the year - based on our limited data from our customers. This is because they get more output when the temperatures are low or the light conditions are poor. The peak power should be the same.

The Sanyo system should cost around £1,000 to £1,500 more based on what we would charge; which would be around £13,000 + 5% VAT.

The Sanyo system could utilise the SB3300 or SB3800 according to a quick check using the Sunny Design tool (making certain assumptions such as south facing, unshaded 30 degree pitch roof and London weather data) but the Sharp may need an SB4000TL.

This will obviously need to be checked properly using all relevant data.

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Thank you Paul - so if roof space is not a problem go with the cheaper Sharps. I've had 2 quotes so far one said go for the Sunny boy 3300 another the 3800. The later as it would not be running at full capacity so last longer.....

Any thoughts ?

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"I am looking at two PV installation of 3.92kw both with a Sunny Boy 3300 Inverter. Both have 16 panels but the Sharp panels are £1,700 less than the Sanyo panels. If they both generate 3.92 kw what am I missing ? is it that the Sanyo's are 19% efficient and the Sharp 15%. If so is the 4% difference worth the extra?"

Hi there

It would appear that you are considering Sharp and Sanyo 245wP panels. These have the same theoretical output but the Sharp's are much larger (1.642m2) and the array will be around 26m2 as opposed to 22m2 for the Sanyo. So the first significant difference is the area required.

If you have the space for them the Sharp's will perform in a similar way; there are some other advantages of the Sanyo in that they claim they work better in higher temperatures and lower light conditions.

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I am looking at two PV installation of 3.92kw both with a Sunny Boy 3300 Inverter. Both have 16 panels but the Sharp panels are £1,700 less than the Sanyo panels. If they both generate 3.92 kw what am I missing ? is it that the Sanyo's are 19% efficient and the Sharp 15%. If so is the 4% difference worth the extra ?

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Hi Roke

Theft can be a problem particularly if you have installed on a flat roof without penetrating the roof.

You would need to ensure that the 'A' frames are securely fastened down and use bolts with tamper proof heads.

 Paul

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Hi Alan

Sanyo are the only readily available, MCS accredited hybrid PV modules in the UK market.As far as we are aware they are the most efficient panels available to us.

To quote Sanyo US website:

"SANYO HIT Power® solar modules are made of 72 hybrid HIT cells that combine two best-of-breed solar technologies -- high efficiency monocrystalline silicon with ultra-thin layers of amorphous silicon. The monocrystalline silicon is sandwiched between the amorphous-Si to offer superior conversion efficiency, excellent temperature characteristics and considerable output under diffuse and low light conditions"

I hope this helps.

Paul

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Hallo Paul

I am planning PV home roof installation on Isle of Skye, which has low end of UK sunlight levels (c740Kwp/yr).  I am planning big domestic array (initially c4kw) & if all's well, extending to 6-7Kw 12 months later.

I am wanting to maximise output to maximise PV contribution to reducing emissions, & am therefore prepared to to pay for more expensive panels to achieve this. Have 2 queries:

Have been unable to pin down what are most efficient MCS approved panels currently available (appreciate while key, not only factor to consider - but key one given my objectives). The best array effeciency I have found to date is Sanyo HIT 240 HDE4 @ 17.3%.  It does appear that there could well be a mono-crystalline panel that could beat that, but because of large range available, am struggling to pin this down (know that some Sunpower panels are more powerful, but yet not MCS accredited).

Secondly, am unclear as to whether hybrid panels perform any better in non-sunlight than MC.  If case - & significant, could well be better choice for Skye. Aware Hybrid have less drop off in hot weather (but little of that here!).

Look forward to hearing from you.

Thanks

Alan 

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Back to flat roofs! If we put panals onto our garage roof they would be easily accessible to everyone - how do we stop thiefs popping up a ladder and removing them? 

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Hi Kate

 Glad that was helpful and hope you are now able to move on to select an installer and start the project.

What area are you based by the way?

Paul

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Hi Paul

Many thanks.  That has put my mind at rest re SWE and the Sanyo hybrids.

 http://www.posterus.s/?p=1247 was a very hard read not made any easier by the author's not being a native-born English speaker. Quite a bit of it was above my head but I was glad I had persevered as I think it provided a text for the attractive set of diagrams I had seen somewhere (and must find again) as well as explaining how the SWE of a-Si was mitigated by the construction of the HIT cells.

Thanks too for the Sanyo contact address but you have provided the information I wanted so I won't need to use it.

Regards

Kate W

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Hi Kate

This is quite a technical area and there is a lot of information on-line. The SWE effect applies to thin film technology in the first 6 months or so and then stabilises for the rest of its life. This is taken into consideration in the performance figures quoted by reputable companies. 

It does not apply to hybrid systems in the same way. If you read all of the Wikipedia entry it says that one of the ways of reducing SWE is to combine layers e.g. hybrid systems.

 Also - see the following quote from http://www.posterus.s/?p=1247   "Advantages of HIT solar cells are numerous ... : good surface passivation, simple and low temperature process and high conversion efficiency. While the base material of the structure is crystalline silicon, the typical degradation (Staebler-Wronski effect) observed in amorphous silicon solar cells does not take place in HIT solar cells. This technology can be used to process very thin wafers (

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Hi Paul

The knowledgeable chap might have quoted evidence but quite possibly my brain switched off and I do not remember.  However I have since read in Wikipaedia about the Staebler-Wronski effect (SWE).  Now I would like to what Sanyo has done to reduce the SWE but I can't find a way to contact them.  On their web site there is an attractive diagram that may explain it but without explanatory text; so I don't even know if it is relevant.

Can you possibly elucidate?  I would be very grateful if you could.

KateW

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Dear Kate W

I have never heard that there are any reliability issues with hybrid modules; or indeed any type of  module lasting longer than another! Sharp mono-crystalline modules have a 20 year guarantee too - but I do not think that this has anything to do with a shorter expected life span.

Did the knowledgable chap offer any evidence as to why this might be the case?

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I had decided to have hybrid panels installed and was in the final throes of deciding which installer to choose when today I visited an open Green Home and spoke to a knowledgeable chap who looked at the specs of the Sanyo HIT240 I had with me and said 'Ah yes, see here - only  a 20 year guarantee.  That's because it has amorphous silicon in it.  With monocrystaline alone, you'd get a 25 year guarantee.'  He went on to say that amorphous silicon can be unreliable, especially at first and it has a shorter life, hence the shorter guarantee. 

Is he talking sense?  I didn't think to ask him but where does one find out this kind of information?

 Please, can anyone tell me.

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Dear RoKe

Shading is generally a problem because even if part of the array is shaded it can cut off the flow of electricity for the whole system.  We would be particularly concerned about shading between 10am and 4pm.

If the shading is as you suggest then it is possible to have 2 arrays controlled by differerent inverters. One could provide power in the morning and the other in the afternoon for example; similar to an east-west configuration.

However it would depend on the level of shading and the relative times. When this is known we could look at the level of energy that could be generated and the financial return to see if it is viable.

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Our flat garage roof and our house roof are both shaded by a tree at different times of the day. Would it be possible to have two panels functioning independently of each other and feeding into the same inverter? And does an export meter usually get fitted at the same time as the panels? 

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As you will see from the article above there are a number of types of panels. Monocrystalline modules are available from a number of manufacturers including Sharp and Kyocera.

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I have been reading of hybrid pv panels - monocrystalline + amorphous - can you tell me what is available and from whom? I have found one from Sharp and are there any sites that compare different types of panels, inverters and what ever other bits of kit are needed? 

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Hi Kate

Sanyo are the only readily available, MCS accredited hybrid PV modules in the UK market. They are extremely efficient (over 17% for the module and 20% for the cells) and there is no monocrystalline module that we know of that is more effective.

We have installed a number of these systems now & our clients are delighted with the results.

 Paul

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I have seen a table showing that hybrid modules are the most efficient. Please could the Solar Energy expert or anyone else who knows, tell me if any manufacturer other than Sanyo makes MCS acceptable hybrid modules. And where do I find them?

A prospective installer told me that his choice of Monocrystalline module was more efficient than my choice of a Hybrid module.  Is this likely?

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Hi Marsh

We have installed solar PV and thermal on flat roofs without any sort of roof penetration. There are 'A' frames that do not require roof penetration for PV modules and we can install solar thermal panels that lie completely flat without loss of efficiency due to the ability to rotate the collector fins during installation.

We would be happy to come and have a look if that would help.

 Paul (paul@eco2solar.co.uk)

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Am thinking of installing PV or solar thermal panels (or both) on my flat-roofed 3 story townhouse.  Does anyone have any experience of a flat roof installation?  Access to the rooftop for maintenance would be difficult (I've never seen it in 8 years!) and I'm concerned that an installation would have an adverse effect on the roof's waterproof-ness.

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