What panels are best value

[Inti]

Given the lower feed in tariff I assume most are reverting to cheaper panels. How do we know which panels are best? Is there a list anywhere that rates PV panels. I have seen comments on this forum that says some panels are good and others are crap but it all seems to be a matter of opinion.

 

[VMan]

depends on a number of factors;
Size of available roof area, (if limited you may have to pay more for smaller panels)
Do you live by the sea ( corrosion certified panels?)
Budget ( Want a reliable system or take the risk for a higher ROI?)
Shading issues (perhaps you may find some modules with power optimisers built in?? )
Aesthetic appearance (you want replacement marly tiles? intergrated system or mount above roof, Standalone?)

Value for money wise, you probably be able to pick a module up for 70p per watt maybe less but what kind of problems are you going to have??

Alot of manufacturers have dropped there prices to allow solar PV to continue at the lower rate, so i assume most installers are using modues they were using before? I know I will be.

in the end it all come down to what the customer can afford and area available really.

 

[solarsparkie]

value is what everyone should be looking for , ive never been wealthy enough to buy cheap.

 

[moggy1968]

yep, have to agree, value is the name of the game, not cheap. there is some cheap sXXX out there. If your looking for an installation go with a reputable installer and see what they have to offer, get a few prices. Don't necessarilly pick the cheapest though, go with the one you feel was most honest and that you can trust and work with. It's a big inverstment so don't try and scrimp on a couple of hundered quid for the sake of taking a chance on the installer.

 

[Inti]

Yes, I know its all about value. But how do I know what the best panels are. The specs can all look good, they are all MCS approved.

If I wanted to buy a new telly I would be able to find meaningful info about why I would buy a Panasonic rather than a Bush. If I was buying a new boiler I would be able to find good reasons for buying a Worcester Bosch rather than a Sabre.

But if I want to compare solar panels I dont seem to be able to find the information.

Is there a review site that compares Solar Panels properly that I can access?

 

[Earthstore]

It is strange, most people seem to think make of panel is the only thing to be concerned about in a pv system.
There is much more to it than that, system design for one.
Due to the present laws of physics the photons that are in a pv cell, when placed in sunlight turn to electrons and move creating energy, they can only move at a certain speed.
Put michlin tyres on a Skoda, will it make it faster than a Porche? If an ugly overweight woman uses expesive perfume would it turn her into a super model?

In my opinion, panel choice is the least important part of a pv system, but what would I know ?

 

[FB.]

In my opinion, panel choice is the least important part of a pv system, but what would I know ?

I agree. Panels are relatively simple compared to an inverter; surely even the Chinese can make a panel which works well.
I'd rather spend money on a decent inverter and good overall design/installation of the system.

*
I have a Power One inverter with two strings of Chinese-built panels and I am happy to see how it goes; someone's gotta try it!
Surely the FiT is intended to encourage experimentation with PV (different panels, inverters etc), rather than all of us sponge easy-money for our own selfish greed; not giving a damn about the eco-friendly-encouraging objective which the FiT subsidy was supposed to achieve.

 

[FB.]

I just ran a hypothetical numbers for my own system (3.75kWp/3.6kW Aurora PVI-3600 inverter):

Retail price with Chinese panels ~ £9000
Retail price with Japanese panels ~ £12000

Scenario #1 (21p FiT rate)

Japanese panels maintain 100% of "as-new" performance for the 25-30 year lifespan; flawless performance.
Chinese panels lose 5% of their remaining output each year (as opposed to the claims of 1% loss per year).
Japanese payback from investment: about £15500 (1.3x the original outlay)
Chinese payback from investment: about £14500 (1.6x the original outlay)

OK, lets now assume that not only do the Japanese panels function very well for a long time, but also that the Chinese panels are 20% less efficient at gathering/converting sunlight than actually quoted, so a 250W Chinese panel actually only manages to peak at 200W, while the Japanese panel manages to achieve 250W.

Japanese payback as before (£15500; 1.3x original outlay)
Chinese payback: £11500 (1.3x original outlay)

So I can make some quite pessimistic assumptions for both degradation of power output over many years, plus that my nominal 250W Chinese panel actually only manages to output as much as a 200W Japanese panel.

 

[Inti]

I just ran a hypothetical numbers for my own system (3.75kWp/3.6kW Aurora PVI-3600 inverter):

Retail price with Chinese panels ~ £9000
Retail price with Japanese panels ~ £12000

Scenario #1 (21p FiT rate)

Japanese panels maintain 100% of "as-new" performance for the 25-30 year lifespan; flawless performance.
Chinese panels lose 5% of their remaining output each year (as opposed to the claims of 1% loss per year).
Japanese payback from investment: about £15500 (1.3x the original outlay)
Chinese payback from investment: about £14500 (1.6x the original outlay)

OK, lets now assume that not only do the Japanese panels function very well for a long time, but also that the Chinese panels are 20% less efficient at gathering/converting sunlight than actually quoted, so a 250W Chinese panel actually only manages to peak at 200W, while the Japanese panel manages to achieve 250W.

Japanese payback as before (£15500; 1.3x original outlay)
Chinese payback: £11500 (1.3x original outlay)

So I can make some quite pessimistic assumptions for both degradation of power output over many years, plus that my nominal 250W Chinese panel actually only manages to output as much as a 200W Japanese panel.

Never read such bunkum in all my life.

Apart from that what you are saying that it doesnt matter what panel i us as long as i have a decent inverter?

The information being posted here backs up what I am saying that there is no information available on what panels are decent or not.

 

[solarsparkie]

FB,

Unless the laws of phisics dont apply to your Jap panels it is not possible that they suffer no degradation , Have you concidered a post with the DECC? your figures are certainly upto the job !

I just ran a hypothetical numbers for my own system (3.75kWp/3.6kW Aurora PVI-3600 inverter):

Retail price with Chinese panels ~ £9000
Retail price with Japanese panels ~ £12000

Scenario #1 (21p FiT rate)

Japanese panels maintain 100% of "as-new" performance for the 25-30 year lifespan; flawless performance.
Chinese panels lose 5% of their remaining output each year (as opposed to the claims of 1% loss per year).
Japanese payback from investment: about £15500 (1.3x the original outlay)
Chinese payback from investment: about £14500 (1.6x the original outlay)

OK, lets now assume that not only do the Japanese panels function very well for a long time, but also that the Chinese panels are 20% less efficient at gathering/converting sunlight than actually quoted, so a 250W Chinese panel actually only manages to peak at 200W, while the Japanese panel manages to achieve 250W.

Japanese payback as before (£15500; 1.3x original outlay)
Chinese payback: £11500 (1.3x original outlay)

So I can make some quite pessimistic assumptions for both degradation of power output over many years, plus that my nominal 250W Chinese panel actually only manages to output as much as a 200W Japanese panel.

 

[FB.]

solarsparkie

I agree that the Japanase panels probably won't maintain 100% - and that just reinforces the argument in favour of Chinese panels, which could suffer much worse degradation and lower-than-promised outputs but still make an attractive investment based on how much money they earn relative to what they cost.

No matter how poor I make the Chinese panels look, or how great I make the Japanese panels look; I still come to the conclusion that Cheap Chinese is more likely to earn a higher return *relative* to how much was paid for the installation.

 

[moggy1968]

ther are good chinese panels and bad chinese panels so don't necessarilly write off all chinese panels as rubbish.

Another factor you may like to consider is the environmental cost of producing the panels. One reason (of many) that chinese panels are cheaper is because they don't have to adhere to the same standards of environmental control as those made in europe. If you are concerned about the environment, which I would hope you are if you are putting in solar PV, then this should be a consideration. Then there are also the issues surrounding the health and safety of workers in China when handling such noxious substances as those that go into panels. H&S costs money. Chinese workers are badly paid, work in poor conditions and do not enjoy the same employment protection, hollidays, sickness cover etc that their european colleagues do. And thats before we get into such things as the human rights issues.

I think there is a bit of over simplification of the manufacturing process of the panels on this thread. They are a complex piece of kit which needs to be made carefully in a properly controlled environment for it to be made well.

As an installer I don't have the historical evidence to back up claims about the performance of cheap vs more expensive panels, what I do know is that having handled both the quality of construction of panels such as sanyo, samsung, Bosch et al is streets ahead of the budget stuff.

There are a whole range of issues to be considered in this decision, not just a few hundred pounds difference in the price of the panels, which makes up a relatively small part of the price of a system.

Anyway, personally I would rather have a BMW than a Dacia Sandero. They both do the same job, the BMW just does it better.

 

[duncs535]

We have used panels from a Uk company - they represent good value - Silicon cells are a pretty constant entity - service and value is where brands have clouded peoples judgement - give them a call ....01228406371

 

[FB.]

Never read such bunkum in all my life.

Apart from that what you are saying that it doesnt matter what panel i us as long as i have a decent inverter?

The information being posted here backs up what I am saying that there is no information available on what panels are decent or not.

Why is my posting from yesterday "bunkum"?

In my example, I have shown that - compared to Japanese panels - even if cheaper Chinese panels turn out to be 20% lower output than what they're supposed to achieve (e.g. only managing 200W from a 250W panel) and that the panels were found to degrade at a five-times-faster-than-promised rate, yet they could still be as economical to purchase as Japanese panels on a £earned for every £cost basis.

Buy cheap, buy twice?
Maybe - but my Chinese panels only cost half of what Sanyo panels would cost, so I can afford to replace my panels after about ten years with whatever I choose and still be no worse off than having purchased Sanyo. In addition, in ten years time, I would expect solar panels to be cheaper and/or much more efficient, so I could probably get a replacement set of Sanyo panels for the same cost as a set of Chinese panels would cost today.

 

[FB.]

The information being posted here backs up what I am saying that there is no information available on what panels are decent or not.

True, there isn't much information available yet and since there are so many micro-climates and variations in solar radiation between locations it can be difficult to make comparisons.

But, taking the pessimistic example for Chinese panels which I gave; I think that I'd notice very quickly if my (Chinese) panels were either:

1.
20% lower output than they're supposed to be.

and/or

2.
5% drop-off in output per year.

In which case, it would only be a year or two before I had sufficient evidence to suggest that my panels were underperforming.
As it happens, my neighbour has a different PV solar array of similar age, similar output and similar orientation to mine, so I will be making direct comparisons and will report accordingly.
As I said; I view part of the FiT as a incentive for me to actually bother to take some readings from my system, rather than carelessly sponge the Fit as a "something for nothing at someone else's expense".

.

There are a handful of estimators around which give us a start point for the most likely average daily, monthly and annual output - so we can all make an educated guess as to what our system should be giving and relate that expected value to the actual value obtained, in the context of how "typical" our weather conditions have been during the time period being measured.

.

 

[moggy1968]

unfortunately though your example takes the most expensive panels on the market, and I find it hard to justify those to my customers. However, I do prefer quality so I go for branded gear such as samsung, bosch or schott. I don't know how they compare in your examples to your chinese cheapy chappies

 

[Inti]

Why is my posting from yesterday "bunkum"?

In my example, I have shown that - compared to Japanese panels - even if cheaper Chinese panels turn out to be 20% lower output than what they're supposed to achieve (e.g. only managing 200W from a 250W panel) and that the panels were found to degrade at a five-times-faster-than-promised rate, yet they could still be as economical to purchase as Japanese panels on a £earned for every £cost basis.

Buy cheap, buy twice?
Maybe - but my Chinese panels only cost half of what Sanyo panels would cost, so I can afford to replace my panels after about ten years with whatever I choose and still be no worse off than having purchased Sanyo. In addition, in ten years time, I would expect solar panels to be cheaper and/or much more efficient, so I could probably get a replacement set of Sanyo panels for the same cost as a set of Chinese panels would cost today.

Ok, sorry I can see now you were trying to make a serious point.

But if you panels are dropping by 5% per year in twenty years they will be dead as the proverbial.

It still doesnt get to the crux of the reason for the post. MCS approved panels have to meet the same performance guarantees.

So if it was that simple shouldn't everyone just buy the cheapest panels they can get their hands on.

I have read all the advice about using reputable installers. How does a reputable installer know what the best panels are? I have seen posts saying avoid the cheap Chinese rubbish and others saying there not all rubbish but no names.

Come on lets tell it how it is. The installers who are saying I wouldnt use these panels are basing that argument on what? Is it they have tried them? If not they are not qualified to comment, If they have tried them then which panels and what was crap about them?

 

[moggy1968]

ok, yingli are ok, suntec ok but IMHO not as well made as samsung, bosch or schott. Sanyo are jus beautifully engineered, but I still find the cost hard to justify unless you are pushed for space.

 

[FB.]

But if you panels are dropping by 5% per year in twenty years they will be dead as the proverbial.

Well, I assumed that it would be a "cooling curve" type of failure rate, where a certain percentage of the remaining cells failed each year. It's kind of like a "half-life" when used to describe the decay of a radioactive substance; it takes as long to go from 100 functional cells to 50 functional cells as it does to go from 50 functional cells to 25 functional cells.

This "cooling curve" style of degradation would be consistent with Sanyo and Sharp's claim of maintaining at least 90% performance after 10 years and 80% performance after 25 years; it takes 10 years to lose the first 10% and then takes another 15 years to lose another 10%.

But it might well turn out to be an unexpected rate of decline in performance; linear, logarithmic or exponential. We'll have to wait a couple of decades to find out.

.

 

[Vegelen]

The latest Suntech 250W Solar panels are excellent value.
They have a panel tolerance of + 0 - 5%, compared with 0 - 10% for the Sanyo HITS.
They are well made, have an excellent warranty, outperform Sanyo Hits in low light conditions but not bright sunlight, where Sanyo hits outperform Suntechs by 12-25% dependent on conditions. If your roof is small, money is no object and you want to optimise generation capacity and pay a 40-55% premium on your system installation costs go for Sanyo Hits.
If your roof can accomodate larger solar panels and generate sufficient capacity for your requirements, go for a cheaper high quality alternative i.e Suntech, Samsung, Rec, Bosch or alternative.
Sanyo HIT's come into their own on clear bright blue sky sunny days.
Then they kick the preverbial a**, outperforming Suntechs by 20-25%.
When cloudy or partially cloudy days return and the light conditions are less favourable, Suntechs come into their own and outperform the Sanyo Hit's clawing back their numerical gains obtained in favourable conditions.
Early research has shown that Sanyo Hit's are likely to generate 15-20% more energy than Suntechs in many parts of mainland UK. If I lived in Scotland, I wouldn't be buying Sanyo HIT's unless my roof was small and I wanted to maximise annual generation capacity by 15-20%.
Conversly, if I lived in Cornwall would I buy Sanyo HIT's?.
Yes, If I was happy paying a 40-55% premium on my system for a 15-20% gain in power on current market prices.
The only time to do that would be on a small roof with limited space when you absolutely need to generate extra energy.
Economically it doesn't make sense to buy Sanyo HITS over a 25 year period if space isn't limited.
Hopefully in future the solar markets obsession with Sanyo HIT's will diminish and their price will reduce to more sensible levels. I personally would buy Sanyo HITS in the UK if roof space wasn't limited, if their panel prices reduced by 20 - 25 % on current market levels because they are a good product.
Hopefully Panasonics recent aquisition of Sanyo will make their Solar business more efficient and price competitive.

Suntech are the largest solar manufacturer in the world who make 1 in 10 of every solar panels sold.

Suntech Solar Panel Manufacturing Facility:

Suntech Power: How Suntech Photovoltaic Cells and Modules are Made (English Version) - YouTube

Video On How Solar Panels Are Made:

h**p://www.youtube.com/watch?v=CT2mHD53wqQ

Before people get hung up on what panels they buy, they should be asking more important questions like?
What orientation is my house- how close to due South am I and if I am not how will that affect the generation output I can achieve?
What is the inclination of my roof?
30 Degrees is ideal. If your roof is shallower or steeper, your ability to generate energy will be affected.
How does shading affect my roof?
If your system is affected by shade you need to make sure your system is properly designed with the right inverters, accomodating the correct number of solar strings etc.
Shade on a few panels can cause the whole system to generate less average power unless the system is designed
to optimise overall generation.
Solar edge with individual microinverters under the solar panels is effective in shady conditions, as well as roofs
with multiple orientations and strings.

How efficient is the Solar Inverter when combined with the Solar Panels chosen and the specific design of the system?
Is it Transformerless and more efficient at 96- 97% or less efficient and a high frequency transformer at 94% with the benefit of galvanic isolation (AC and DC are permanently isolated from one another by the transformer).
% quoted above are for SMA inverters.

How much power does your chosen Solar Inverter use at night while on standby? 0.5W or 1W or more.

Will your chosen inverters be easy to monitor using the internet or will you have to buy expensive monitors
to keep an eye on its performance?

How good a warranty will the inverter have?
Solar Edge - 12 years.
SMA - 5 years.

Their are many questions to ask depending on your individual requirements before taking the solar plunge.
Dont rush into any decision you make, do your homework before getting a solar salesman round.
Get quotes from many solar installers.
Do research on the company you've chosen- Are they a member of REA, so when you hand them a deposit and they go bankrupt you will get it back.

If you cant afford to loose the deposit or any money paid to the company if they went bankrupt, pay for the installation on your credit card at a 2.5% charge. Your credit card insurance will cover you.

NB: Before the Scaffolders arrive to install your solar system, have you checked with your Home insurers regarding liability for any accidents?

Are the Solar installers MCS acredited-- No Fits if they are not!

Do they have public liability insurance for their workers in case one falls off the roof, or through it?

Once the system is installed- Have you told your House Insurers that you've got a solar system on the roof and asked them to include it in your Buildings insurance?

Hope the above is of some use to anyone considering solar out there.