Sunday, March 18, 2012

Tips for choosing solar panels

Solar panels cost anywhere from under a hundred dollars to thousands. When choosing solar panels for your solar power system, there are a number of factors worth considering. Don't base a purchase decision on solar panel cost alone - the following are a few tips for choosing solar modules.

 

Solar panel cost

 The cost of a solar panel is determined in part by the size (in Watts), the physical size, the brand, the durability / longevity (or warranty period) and any certifications the solar panel might have. Choosing a solar panel on price alone is not wise, as it may not fit the area you wish to install it, may not have the necessary certifications to qualify for government rebates, or may not have the warranty required to help ensure economic payback of the power produced.

Durability / Longevity / Warranty

The durability or longevity of a solar panel is important for a number of reasons - it can be an indicator of the manufacturer's confidence in its products. Reputable solar panels will have warranty a period of 25 years. All of our key panels; REC Solar, Hanwha SolarOne, Suntech and Sanyo  feature this 25 year warranty period.

However, an important point to remember about warranty is that it will only be honoured for as long as the company operates. It's another reason to select a well known brand of solar panel rather than an obscure brand that may disappear overnight. As you most likely won't be able to buy panels directly from the manufacturer, your selection of retailer is also important. Choose a company that is a service agent for solar panel warranty work for the particular manufacturer you select so if you do strike a problem, the turnaround time to a resolution will be far faster.

Size and Watts

The size of the solar panel in Watts will directly affect the cost, as solar panels are usually priced (and compared) in dollars per Watt.  Watts are related to the output of each panel; meaning a 100Watt panel under ideal conditions will generate 100 Watts of electricity each hour and a 200 Watt panel will generate 200 Watts each hour. Therefore expect to pay double the price for the 200 Watt panel, compared to the 100 Watt panel.   

The output of a panel also affects the physical size of the panel, meaning the 200Watt panel will be larger in size to the 100 Watt panel. . The type of solar cells used in its production also determines the size of the solar panel. They key issue to consider is that your system overall has enough Watts to power your appliances, and that the solar panels will physically fit in the area you wish to install them.

While thin film panels are quite a bit cheaper than mono-crystalline and poly-crystalline, they do require a great deal more roof space. Your northerly facing roof space is very valuable solar power real estate, so you'll need to consider carefully your future plans. If you believe at some stage you will wish to add on more panels, you need to ensure you'll have the space to do so, otherwise you may find you'll need to replace thin film panels well before the end of their serviceable life.

Types of solar cells used

There are 3 main types of solar cells. 

Monocrystalline silicon is the most efficient and produces the smallest solar cells, and therefore the smallest panels. Monocrystalline solar panels are also the most expensive. 

Polycrystalline (or multi-crystalline) silicon produces the next most efficient type of solar cell and is the most popular choice as it provides an excellent balance of performance and economy. Recent improvements in polycrystalline panel technology are bringing these modules closer to monocrystalline in size, efficiency and heat tolerance characteristics. The European market has now adopted polycrystalline as the standard.

Amorphous (or thin-film) silicon uses the least amount of silicon and also produces the least efficient solar cells. This means thin film system take up more area than the other two; an important factor to consider in relation to possible future upgrades; i.e. if you'll have enough space left to do so.

In most situations, we recommend the use of quality polycrystalline solar panels for home solar power systems.

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