The truth about Solar Panel performance and temperature

How does the Aussie heat affect your solar panel performance?

One of the main factors that makes Solar Power so popular over here (apart from the Aussie Pollies throwing wads of money at in in the form of Solar rebates and Solar Feed In Tariffs) is the fact that the Sun is so damn strong down here.

It’s not rocket science to work out why Solar Power hasn’t really taken off in less sunny climes like my homeland; grey, drizzly old England.

In fact the same 1.5kW system on a roof of my Mum’s quaint cottage in Northern England will produce 45% less energy than if it was on my roof here in Sunny Adelaide.

So does that mean the more sun the better, when it comes to generating Solar Power?

That would kind of make sense, right?

Unfortunately, as with most things in this life, it is a bit more complicated than that. [Read more…]

Are you getting the best Solar Panels? The Top 10 Things To Check

the best solar panels

How do you know if they are going to perform on your roof?

There are a bewildering array of solar panel brands out there. How do you sort the wheat from the solar chaff and be sure you are getting the best solar panels for your roof?

My advice is go thru the spec sheet for each panel and judge them on the following criteria.

If you haven’t got a spec sheet, then get another quote!

If the spec sheet combined with the quote doesn’t have the answers, call up the solar supplier and ask. If they don’t know the answers, that’s a bad sign.

The Top 10 Criteria [Read more…]

Solar Panel Warranties – How to make sure yours is worth more than the paper it is written on:

All solar panels should come with 2 types of warranty:

  • Power Output Warranty : usually 20-30 years
  • Material Warranty : usually 2 to 10 years

1. The Power Output Warranty

This covers the power from the panels. Usually if the power drops to less than 80% of the specification in the first 20-30 years, you can make a claim on the warranty.

That’s all well and good but you need to be confident that you will firstly be able to measure and prove that the power has dropped, and secondly be able to contact the correct company to get any warranty claims honored.

Ask to see the warranty details in writing. Get the installer/salesperson to show you where it states how the power from your panels will be measured if you suspect that the power has dropped, who will measure it and if they will charge you for the privilege.

Also ask them to show you where it says how the warranty claim will be handled, who is responsible for honoring it and what costs you might incur. Will they charge you to remove, ship and test the faulty panel and then ship and install the new solar panel.

If your solar installer or salesperson can’t answer these questions then that is a sign that they are badly trained or inexperienced or both.

If the warranty is covered by the installing firm, ask what the backup is if they are not around in 20 years – (This even applies to the bigger solar installers – one thing the world has learned recently is that even huge companies can go bust if the economy changes…). If you have to go back to the solar panel manufacturer, then go to the manufacturers website and see if you can find warranty details. If you can’t find the website or the warranty details that is a bad sign…

Another great question to ask is: “What % of your revenue do you put aside for future warranty claims?” and also “What % of the solar panel manufacturer’s revenue is put aside for future warranty claims”.

The final thing to check out is whether this warranty is “linear” or “stepped”. A linear warranty of 80% (i.e. a 20% power drop) over 20 years would cover you if the output dropped by more than a twentieth of that 20% in the first year (i.e. 1%), then 2% in the second year and so on… at that linear rate of 1% per year until the solar panels were 20 years old.

Linear warranties are rare, but some of the more expensive panels do have them. The more common “stepped” warranty means that, for the “80% over 20 years” example, your panels can lose 19% in the first year and you won’t be covered unless they lose another 1% in the remaining 19 years to get under that 80% threshold.

2. The Material Warranty

The material warranty (2-10 years) is usually for defects that may cause the power of your panels to drop – but don’t cause the power to drop below the “power output warranty” threshold.

So if you have a power output warranty of “80% over 20 years” and some water gets into one of your panels causing the overall system power to drop 19% – this would be covered by the “material warranty”, not the “power output warranty”.

This can be for stuff like delamination of the backing sheet, discoloration of the solar panels (can look really naff!), solder joints coming undone and bypass diodes failing.

Again – ask your solar installer or sales person to give you a comprehensive list of things that are covered by this warranty.

Finally: watch out for get out clauses

In some of the small print in the terms and conditions published by the bottom end of the solar market, I’ve seen clauses that say your warranty isn’t valid unless you get your system “serviced” every 2 years.

If you have one of these clauses, find out exactly what defines “serviced” and how much it is going to cost. This is especially important if you are buying a really cheap solar system with panels of questionable lifespan. The last thing you want is for your panels to fail after 3 years and then have the warranty knocked back because you didn’t get your panels “serviced” within 2 years!

How Important Is Efficiency When Choosing A Solar Panel?

I get a lot of emails from people asking “Which is the most efficient solar panel on the market?”.

Last time I checked, the awesomely awesome Sanyo HIT 195DA3 (note: now manufactured under the Panasonic brand) laid claim to the most efficient panels in production at a whopping 20.5% panel efficiency!

(And before you SunPower fans swamp me with emails – yes, I understand that this is including light coming into the back side of the panel, which is would require special mounting – see the pic below. On a typical roof, the Sunpower E20 327W will be the most efficient at 20.4% panel efficiency)

Mounting a solar panel to allow "backside irradiance"

An example of Sanyo HIT solar panel mounting to maximise efficiency.

But whilst solar panel manufacturers like SunPower and Sanyo battle it out for the “most efficient panel” gong, the question we really need to ask is: “Is the most efficient panel the best option for your roof?”.

[Read more…]

Is this the daftest solar power promotion in Australia?

Watching the late movie on TV last night the most ridiculous ad for solar power I have ever seen came on.

I nearly fell off my sofa when I saw that if you buy a 1.5kW solar system from these guys, they’ll throw in a ‘free’ 50″ plasma TV.

Large Plasma TV’s are, of course, the most energy inefficient form of watching telly known to man. Apart from maybe hiring your own multiplex cinema every evening.

Let’s do some sums:

Having a quick look on energyrating.gov.au tells me that a typical 50 inch plasma with typical usage patterns will suck about 850kWh of electricity per year.

So that’s 2.3kWh of electricity per day.

A good quality 1.5kW solar system in Adelaide will produce approximately 6.6kWh per day.

So that ‘free’ plasma is going to reduce the output of your $10,000 (gross of all rebates) solar power system by 35%.

And if you were planning on exporting that 2.3kWh of electricity to take advantage of SA’s generous net Feed In Tariff then you would be losing $503 per year thanks to the ‘free’ plasma TV.

What a great offer!

P.S. The number one sign of a great solar panel installer is that they actually care about your current and future electricity usage so that you will get the maximum benefit and maximum payback from your shiny new solar panels. If the installer doesn’t care about energy efficiency, quickly move on to someone that does.

German magazine tests 10 solar panels

In September 2006, respected solar power magazine, Photon International, bolted 10 different solar panel manufacturers panels to a test rig in Germany and measured the performance of those panels over 12 months.

The panels they tested were:

  • Photwatt
  • Solarworld
  • Shell Solar
  • BP Solar
  • Solar Fabrik
  • Isofoton
  • Kyocera
  • Sunways
  • Sanyo
  • Sharp

The results of the testing were that the difference in power produced across all the solar panel brands was 9.85%.

The results are shown here:

Solar Panel test

From Photon International Magazine September 2007

As you can see Photwatt panels came top.

Interestingly the Sanyo panels which many vendors claim are the “best of the best”, came second last. Apparently Sanyo’s excuse was that the magazine were supplied with defective panels, oh and the dog ate their homework too I imagine.

The well known brand “Sharp” came a surprising last place.

Of course this test was 3 years ago. I imagine that the losers of this test have upped their game in recent years. The latest issue of the magazine has some more recent results in it as soon as it arrives in the mail from sunny Germany, I’ll let you know the latest winners.

Wouldn’t it be great to put the top 10 most popular Australia panels through a similar test (including the many ‘own-brand’ panels). Let me know if you think that is a good idea in the comments. If I get enough interest I may organise such a test myself. Watch this space…

Solar Power Isn’t Perfect (but it’s still worth it!)

Making solar panels requires old-fashioned coal-fired power

The city of Bay City, Michigan has an interest in solar power, and in this article (http://www.mlive.com/news/bay-city/index.ssf/2009/06/making_solar_panels_requires_o.html) the pros and cons of using this alternative form of clean energy are dissected and stacked against one another to determine whether solar power is really the best way forward for energy production.

[Read more…]

Recycling and Solar Panels

No-one knows how long a solar panel should last – currently, some are over 30 years old and still working well. However, it is anticipated that an increasing number will need to be replaced. In today’s worldwide drive to save energy wherever possible, it would be better to recycle.

[Read more…]

Dodgy Solar Panels Landing In Australia

Time is running out for the Australian Federal Governments ‘grid connect solar power rebate’. Unfortunately, the $8000 rebate has been tainted by unethical, ‘overnight’ companies duping consumers with inferior equipment and ‘too good to be true’ deals.

Of course, there are genuine companies selling genuine products within the solar industry, but the emergence of many underhand tactics continues to threaten an unsuspecting public.

[Read more…]

Cambridge Uni Boffins Hoping To Win Aussie Solar Powered Car Race

Cambridge University students, in the UK predict their new solar powered car will be capable of cruising at 60mph, and intend to enter the up and coming World Solar Challenge.

Equipped with a 6m2 ‘skin’ of silicon cells, the journey, from Darwin, will take the car, AKA ‘Bethany’, across Australia’s arduous outback, over three thousand kilometres, to Adelaide. Bethany’s outer skin covers a highly efficient electric car, one its creators say could be a prototype for future ‘green transport’.

[Read more…]

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