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Starting Your Smart Investment of Home Solar Panels

 Residential solar panel systems admittedly have beginning costs that are much higher than when power for everyday use originates from the local utilities or gas. This seemingly less expense brought about by the latter makes most home owners and builders decide on siding on the conventional power source.

 Still, it should be clearly explained that the solar panels for home use of today are not competitive with regards to costs and expenses. Right now, most solar power proponents not only fight for the home solar panels because of their environmental benefits, but it can likewise be an economical reason.

As years go by, conventional fuel as well as electricity is becoming more expensive; this makes solar panel systems more advantageous. And not only the solar panels for home use are cost-effective but sun-powered water heaters likewise offer great savings for the users as an effective means of solar heating. It is shown that the water heaters’ expenses and costs are at least 50 percent lower than the electric heaters.

 Besides the possible savings, there are likewise local and state financial incentives as well as tax credits which will sharply decrease the cost in the end. Solar panel systems indeed are the best alternative when comes to finding ways to replace the conventional power source. 

 Thinking about utilizing solar energy as a way of greening your life and lightening your environmental footprint? When choosing panels for your solar power system, there are a number of factors worth considering.

When choosing panels for your solar power system, there are a number of factors worth considering.

Solar panel costs

Costs vary widely depending upon the type, wattage and brand of panel. Additionally, the margins that stockists apply to their panels can differ tremendously.

You can pick up cheap panels on places like eBay, but given the size of the investment this can be risky if the merchant suddenly disappears or the sale of the panel is a sideline rather than part of the merchant’s core business focus. You’ll be spending a lot of cash, so you’ll want to ensure the person/business you’re buying from are renewable energy experts and in it for the long haul.

Calculating how many solar panels you’ll need

  This is one of the most asked questions and there’s no set answer – it’s all down to your electricity consumption, geography and other elements of your system. For example, if you have a stand alone power system as opposed to a mains grid connect, the capacity of your deep cycle batteries play a major role.

Here’s a quick and dirty formula. It’s based on watts rather than amps (amps would be more accurate) for the sake of convenience.

Jot down all the appliances you use.

Next to each, record their wattage.

Also next to each, record the numbers of hours of use.

Get a total for each and add those figures up.

Using the solar peak hours chart, gauge how many peak sun hours you get a day.

Divide the total wattage by the peak sun hours.

You’ll have a very rough guesstimate of the total wattage of panels you’ll need.

To gain a more accurate idea, some solar panel stores such as Energy Matters offer detailed solar panel calculators that will take into account issues like your geography and other elements of the system; e.g. whether you’ll have a grid connect or stand alone system and how much of your electricity you wish to generate via solar power.

Solar panels still aren’t dirt cheap, so if you’re switching to solar it’s a great time to also carefully evaluate your electricity use. The less juice you need, the fewer panels you’ll need and you’ll save a ton of cash. Don’t forget that many governments around the world also offer substantial solar panel rebates which can really help remove the financial sting from your purchase!

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 for economic payback of the power produced.

Durability / Longevity / Warranty

  The durability or longevity of a solar panel is important for a number of reasons. Firstly, if the solar panel only has a 10 year warranty and it is used in a grid connect system you would expect the solar panel to produce enough power to pay for itself within 10 years.

Also, if the panel is to be used in a critical system you shouldn’t risk installing solar panels that aren’t as robust as the others. Reputable solar panels will have warranty a period of 25 years.

 Reputable solar panels will have warranty a period of 25 years.Solar Panel Size and Wattage

The size of the solar panel in Watts will directly affect the price, as solar panels are usually priced (and compared) in dollars per Watt.

Watts are related to the output of each panel; meaning a 100 Watt 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 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 200 Watt 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.

The size of the solar panel in Watts will directly affect the price, as solar panels are usually priced (and compared) in dollars per Watt. Solar Panel Efficiency

  There’s much debate about efficiency in solar panels, i.e. how effective the panel is in converting sunlight to electricity; but the key point to remember is that a 100 watt solar panel will produce 100 watts; regardless of its efficiency ratings.


Solar Cell Type

There are 3 main types of solar cells.

Mono-crystalline silicon

The most efficient and produces the smallest solar cells, and therefore the smallest panels.

Poly-crystalline (or multi-crystalline) silicon

Produces the next most efficient type of cells, but equivalent wattage panels are larger than their monocrystalline counterparts.

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, but it has the advantage of offering flexible panels that can be used on curved or irregular surfaces not suited to solid panels.

Solar Panel Suitability

Mono-crystalline and multi-crystalline work very well in bright cool conditions, whereas amorphous (thin-film) silicon will be more efficient at higher temperatures.

 We generally recommend monocrystalline or multi-crystalline for large unshaded roofs, and amorphous panels for roofs with partial shading.

 Regardless of the technology currently in use, a solar panel in full shade will only generate a small fraction of its rated capacity; so the “shade tolerant” features you may see advertised can be somewhat misleading.

 A solar panel is made up of photovoltaic cells, usually 36 all told, varying in size depending upon the watt/amp rating of the panel. These cells are made from two very thin silicon wafers approximately 1 mm thick; one with a positive charge and the other negatively charged. 

When exposed to the sun’s rays, electron activity is generated which is captured by a grid of very fine finger-like electrical contacts distributed across the panel. This is then channeled through the junction box on the back of the panel and emerges as DC (direct current) electricity.
Closeup of a polycrystalline cell showing the fingers of conductor material

Covering the silicon wafers is a layer of toughened glass, usually around 3mm thick. It has to be strong enough to withstand hail, extreme temperatures and a degree of flexing, but thin enough not to filter out or reflect appreciable amounts of light.

As silicon (which is made from sand) is also reflective; it requires a thin layer of anti-reflective material.

The back of the solar panel is made from aluminium and the panel is set into an aluminium frame.

Once the juice exits the panels, it travels along cabling. The size/diameter of cabling is of critical importance.

Cabling is critical

Once the juice exits the panels, it travels along cabling. The size/diameter of cabling is of critical importance. If it’s too thin for the panel’s output and distance to be covered, it’s a little like trying to pour a large volume of water through a small opening. There will be a loss of electricity as it will convert to heat along the cable to the point the cabling can burn out.

This handy DC cabling size calculator can tell you what diameter cable you’ll need for amp rating of the panel you buy and the distance there will be between the panel and the solar regulator or inverter.

Makes it all sound relatively simple doesn’t it? I’m still in awe that sun shining on silicon and a bit of wiring can generate electricity though, but each time I try to delve further into how panels work, my brain says “let’s go check out the latest Dilbert comic strip instead” 🙂

Monocrystalline vs Polycrystalline (Multicrystalline)

Rigid solar panels cell are usually made up of either monocrystalline or polycrystalline (aka multicrystalline) cells. Monocrystalline cells are cut from a chunk of silicon that has been grown from a single crystal. These are used in the more expensive types of solar panels and are more efficient in converting the sun’s rays to electricity.

A polycrystalline cell is cut from multifaceted silicon crystal. More surface area is required due to inherent flaws and these panels are less efficient in converting the sun’s rays. However, polycrystalline technology has closed up the performance gap in recent years.

Also, a 120 watt rated monocrystalline solar panel and a 120 watt molycrystalline panel are essentially the same thing – they crank out the amount of electricity.

The easiest way to visually identify the difference between a monocrystalline and polycrystalline panel is the polycrystalline has a shattered glass look as shown in the image above. Monocrystalline cells tend to be uniform in appearance.

Thin film solar panels

Thin film panels are created by the application of a thin layer of silicon directly onto various materials. It’s applied in such a way that flexible panels can be made. The need for less silicon will reduce manufacturing costs significantly in the time ahead.

Thin film panels are also less efficient that polycrystalline and monocrystalline panels, so a larger surface area is required. Again, peformance in thin film technology is constantly improving in the area of efficiency. Given the processes to create thin film, cheaper alternatives to silicon can also be used, such as cadmium telluride; although cadmium is frowned upon by many as it’s a heavy metal.

Sunlight isn't the same around the world. Even without cloud cover, different places on Earth receive varying levels of solar radiation.

The sun and geography

Sunlight isn’t the same around the world. Even without cloud cover, different places on Earth receive varying levels of solar radiation. When calculating the size and number of solar panels you’ll need; kilowatts-hours per square metre (kwH/m2), or more commonly known as solar “peak hours” need to be taken into account. This is the number of hours a day when the sun has maximum punch in relation to potential for electricity generation.

These peak hours are also measured against average winter sun; the time of the year when you’ll have the least sunlight. 

You can get an idea of how many peak hours of sunlight in your area by using using this solar panel calculator – the figure to look for once you type in your area is the “Solar Irradiation:” Whatever the kW/m2/d figure is, that’s your peak sun hours.

Solar panel orientation and angle

Again, this is dependent upon where you are in the world and also greatly varies with the season.

During summer, the sun sits a lot higher in the sky that during winter, so it’s best to “chase the sun” so you can to get the maximum oomph from your panels. However, this is difficult to achieve if the panels are sitting on your roof, so a happy medium is usually found. Basically, if you have the angle good enough to get you through the winter months, you’ll have no problems during the summer.

The general guidelines are:

Solar panels should face South in the Northern Hemisphere and North in the Southern Hemisphere

A solar panel’s angle should be set to the equivalent of your your latitude plus 15 degrees during winter, or minus 15 degrees in summer.

Solar panels and shade

Solar panels and shade simply don’t mix. While some panels claim to be shade tolerant, you will lose substantial charging power even if only a partial area of the panels is affected by shade. If one quarter of the panel cell area is shaded, the juice being cranked out will be virtually nil.

Solar panel care

One of the wonderful thing about solar panels is there’s no moving parts, therefore next to no maintenance! A wipe/brush down occasionally will help prevent buildup of dust and grime that can impact on effectiveness; but usually the rain will also take care of this. Other than that, a visual inspection of frame seals and wiring from the junction box is all that’s really needed.

Solar Panels are typically installed on rooftops, building tops, or stand-alone facilities. It is vital to install your solar panel so that it gets the most direct sun exposure

Solar Panel Installation Tips

Solar Panels are typically installed on rooftops, building tops, or stand-alone facilities. It is vital to install your solar panel so that it gets the most direct sun exposure. You want to make sure your solar panel is maximally effective year round. To do this, there are several web-based solar resources to help you properly set up and install your solar panels by tracking the position of the sun in the sky over the course of the year.

 Position your solar panel in direct sunlight

Solar Panels perform at optimum capacity when placed in direct sunlight. Try to position your photovoltaic array directly under the noontime sun for maximum efficiency from your photovoltaic unit.

Notice obstructions to sunlight

 Remove all items unnessary items or trim branches that may be blocking sunlight to your solar unit. Trace the path of the sun in the sky to determine if an object is casting a shadow over your solar photovoltaic panels. If this is the case, then the operating efficiency of your unit will undoubtedly suffer.

Mounting your Solar Panel

Solar Panel Mounts are used to install photovoltaic solar panels. Solar panel mounts come in three main varieties: pole mounts, roof-ground mounts, and flush mounts. Using these mounts, you can install your solar panel onto an RV, on top of or against the side of a pole, on your roof, or even install them as a free-standing unit. You can learn more about installing solar panels using mounts in our mounts section.

Water pumping with solar panels

 A good way to put solar panels to use is to install a solar-powered water pump for your well. Although windmills have traditionally been used to power such systems, a solar-powered system works just as well, and is equally friendly to the environment.

Your Well Pump

It is important to choose a quality well pump for use with your solar powered well pump system, one that makes the best use of your power and doesn’t require an inefficient, wasteful transformer. Your well drilling provider is likely to offer you the industry standard well pump, a 220 volt alternating current model. The problem with such a high-voltage pump system is that the required transformer is extremely wasteful and can be a huge strain on your inverter during startup. This can cause the power to home to dip, and the lights to dim, which can cause a full-out inverter failure unless you have a top-quality inverter. Avoid such a high voltage system if you can, and instead, opt for a 120 volt AC model, which is much more efficient and does not put nearly as much of a burden on your inverter.

The Solar Panel

Your solar panel does not have to have a very high wattage rating in order to run your solar pump, just check with your well-drilling company to determine what wattage rating you need from your solar panel. An important consideration when setting up an outdoor solar panel system for your well pump is to ensure that you purchase a mounting rack that offers plenty of clearance between the ground and your solar panel and keep in it an open area away from trees. You don’t want any large pets, floodwater, or falling branches to damage your system.

Solar Panels and Power Meters

As you purchase more and more solar panels for your home, your reliance on the city’s power grid will progressively decline until your power meter doesn’t turn at all. As you continue to buy solar panels, you wonder, what happens beyond that point?

What happens on the days when my home produces more energy from solar panels that it needs? Contact San Diego Gas & Electric or your local city-town electrical provider for that information. Contact your city and town government for tax incentives and ways that your local utility can pay you for selling your extra electricity to them.

Also, we recommend using a true sine wave inverter with your solar powered pump system. True Sine wave inverters tend to work better when motors are involved (such as those found in a water pump).

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