Buyers Guide for buying Solar PV Panels – The things you should know to make an informed decision

Buyers Guide for buying Solar PV Panels – The things you should know to make an informed decision

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Ever wondered why a solar panel with the exact same rating is more expensive than another one ? Many people think one 200 watt solar panel would give the same performance as another 200 watt but this couldn’t be further from the truth.

There is a reason and solar panels are far more complicated than most people realise.

This quick use guide is to help, installers, normal home owners and businesses to make better decisions when choosing solar panels. It’s designed to keep you from making obvious mistakes by giving you the knowledge you need. It is not designed to be definitive but to give you the key information you should know to keep you on the straight and narrow.

“So let’s start with a question. Which of the following solar PV panels below would you buy”?

Yes, it is daunting at first but there are some basic rules you can follow.

Only buy a branded product from an authorised supply chain for that product. This will ensure you buy good manufactured genuine product and not counterfeit examples of the genuine product. The manufacturer will be able to confirm that the source is genuine.

Determine whether you want premium panels or normal panels. This is hugely important. Solar Panels are like cars, there are low cost ones and high cost ones and you get what you pay for as in any other industry. In this industry, you pay for performance. Two panels both equally rated at 200 watts(p) does not mean they are the same or will have the same performance.

Counterfeit panels, yes, we are going to mention it again. Obviously they probably won’t last very long as they are being produced in the same way as counterfeit clothes and counterfeit vodka. They are designed to separate you from your money and the person putting these on the market will be long gone when you realise your mistake. You may also have genuine people distributing solar panels that are counterfeit, untested/uncertified and don’t even realise they are doing so. Even distributors have been caught out.

https://www.pv-tech.org/news/ul_warns_of_counterfeit_ul_mark_on_pv_panels

Look at the picture below, we have just taken this from one of the big online sales websites we all use everyday, rhymes with GEEBAY. It is the front and back picture of a large consignment of solar panels for sale. 

Question: should I buy these solar panels. Is there anything that stands out that I can assess to help me in my decision?

Here is a list of all the things that jump out about this product.

  1. It is being sold on a generic online website. (risky)
  2. The label is unbranded. (definitely not good)
  3. It’s label says it is certified “by” IEC61215. (typical mistake of fake labels)
  4. The label is not straight and is full of air bubbles. (more evidence of fake)
  5. There are no MCX plug and play connectors on the panel. (really cheap)
  6. It’s likely that the technical information is false so matching this with an inverter will be a challenge.

So there are too many warning signs here that indicate this is high risk of being a poor product and is potentially designed to part you from your money. Of course the price will be very attractive. !!!.  The product would arrive, look new and like a typical solar panel to an unskilled eye. In all likelihood it would probably fail very quickly within 1 to 5 years if it even lasted that long. It is also typical that these panels only produce 50% to 60% of claimed output.

So far we have just talked about counterfeit panels that will actually work. Below is an example of a counterfeit panel which circulated in the last 24 months. You can see on the left hand side the fake panel which had printed cells, ie. from a printer (ink) so was the ultimate fake. The genuine panel is on the right half of the picture. To the normal person, these panels looked genuine and had the labels of a genuine product on the market. In fact the fake panel looked more genuine than the actual real product.

FIRST RULE OF THUMB – WATCH FOR FAKES OR POOR QUALITY….

“And there is one other thing that jumped out about this solar panel above, in fact it was the first thing that jumped out. It has a single bus bar. This is an important consideration”

The panel above has cells with 1 bus bar. Example 1BB cells below. 

Bus Bars are one rule of thumb to work out whether the solar panels are older technology or newer more efficient technology. Bus bars move the current through the semiconductor cells and the more bus bars, the newer the technology and hence the more efficient and higher performance the panel will have. Current mainstream mass market panels are not 2BB (fairly old at this stage) and 3BB are also getting old as well  (2 or 3 bus bars). Current state of the art and premium is 4BB moving to 5BB and next generation is 6BB. The more bus bars, the more efficient the panel will be.

Bus Bars are the shiny metal lines running down a cell. They carry the current from the semiconductor cell and the more bus bars the more efficiency and the less current each bus bar has to carry. Next time you look at a solar panel, count the number of bus bars.

The lower number of bus bars increases the risk of shorting and panel damage, the more bus bars, the newer the technology and more efficient the transfer of energy from the semiconductor cell.

SECOND RULE OF THUMB – THE HIGHER NUMBER OF BUS BARS ON THE CELL MEANS THE NEWER THE TECHNOLOGY AND THE HIGHER THE EFFICIENCY….

Next, lets discuss material and grading.

Monocrystalline versus Polycrystalline panels. Monocrystalline cells have higher efficiency than Polycrystalline as Mono is made out of the highest quality silicon.

You can spot Poly solar panels everywhere as they are the solar panels with blue reflecting cells. Mono are blacker in colour and hence absorb more light. Poly has a typical efficiency of 14%-16% but Mono can be as high as 20% efficiency. HONE PERC cells have an efficiency of over 19% and designed to harvest daylight so as to run cooler in sunshine and harvest a much higher level of power in cloud and winter.

Next you must consider that perfect Grade A cells are used in reputable panel manufacturing. Grade B cells which have visual defects are available to buy. Grade C cells which have visual and electrical defects and should never end up in panels but unfortunately do.

Grade B & Grade C cells typically end up in panels which get sold into the intermediate markets and get re-sold on without any warranty sometimes to unsuspecting customers. Unless you are skilled at semiconductor wafer quality control, you may not even notice.

There is enough information on the web to google on this particular subject of cell types.

THIRD RULE OF THUMB – IF YOU ARE CONCERNED ABOUT EFFICIENCY AND PERFORMANCE, THEN CHOOSE MONO OVER POLY….

“Now we need to talk about the more advanced developments of semiconductor cell design”

We need to talk about selective emitters and primarily PERC, PERL and PERT. We will specifically talk about PERC to explain these as this is our core product.

PERC stands for Passivated Emitter and Rear Cell. PERC cell technology defines a solar cell architecture that differs from the standard Solar PV cell architecture that has been in use for the last three decades.

Due to the high performance, It is expected that PERC semiconductor cell architecture will surpass standard solar pv cells sometime in the next decade as manufacturers play catch-up and standard solar pv cell use will shrink away by 2030.

“PERC means one main thing, much higher performance but it does mean many other things as well”.

We will use HONE PERC semiconductor cells as an example explanation and this technology has been designed to operate in a specific way with daylight. Below we can see the architecture of a standard solar pv cell. This semiconductor architecture originates from the original bell labs designs for the space program in the 60’s. It is very basic semiconductor architecture and is in nearly all Solar PV panels today.

In the 2nd diagram below, we can see the structure of HONE PERC semiconductor architecture. It is more advanced and has numerous benefits not withstanding higher performance over standard solar pv cells with typically 9% better output. HONE PERC cells are primarily designed to work from daylight and to diffuse light as it enters the cell. This is done via the enhanced surface structure to remove the dependency on having to face south. This daylight methodology also allows the semiconductor to operate at lower temperatures and further enhance performance. Another feature of these cells is that it reflects light back and can harvest that same light twice unlike standard solar pv cells.

FOURTH RULE OF THUMB – IF YOU ARE CONCERNED ABOUT EFFICIENCY AND PERFORMANCE, THEN CHOOSE ADVANCED SEMICONDUCTOR STRUCTURES SUCH AS PERC CELLS AS THESE ARE THE MOST POWERFUL….

Warranties: Also note that some panels have a 10 year warranty and it is stated as such for both performance and product in the small print. This is not the situation with market leading product which will have 25 year warranties on performance and 10 years on product. Don’t assume all panels have the same warranty.

THE PROOF…

And if you need any proof of the value of quality and investing in better technology panels, have a look at a sample of an ongoing long term study of HONE Daylight Electric Panels versus standard Solar PV Semiconductor Cells. This study to be published later this year involves the monitoring of many different installations of HONE and Solar PV installations.

The data below shows this leading German Solar PV system produced 172 kWhrs per KW(p) installed since Jan 1st. You can see the inconsistency of weather and lack of sunlight in performance with February actually producing more energy than March. This system is located in the West of Ireland, a challenging location for these types of renewable systems.

We can also look below at the data screenshot from the 13th May, 2019 at 7:30am of the same Solar PV system with the output still at 0 KW of production waiting for the system to start producing energy.

NOW Let’s contrast that with the HONE Daylight Electric System below in the same location with consistent performance and producing 394 kWhrs per KW(p) installed since the beginning of the year 2019. This is 230% more production per KW(p) installed than the leading Solar PV System above. In fact, the HONE system produced more energy per KW(p) in January than the Solar PV system produced in March. This is what Daylight Optimised Semiconductor Technology is all about. All these systems are being monitored on an independent platform and are installed in peoples homes.

And by contrast at 7:30am this morning the 13th May 2019, the same HONE Daylight System shown below is already producing 446 watts of output which is 24.7% of its peak rating at 7:30am. This is real performance and this is why choosing cheap in electric panels will probably be more expensive than you realise.

FIFTH RULE OF THUMB –  YOU GET WHAT YOU PAY FOR….

SUMMARY….

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