Today the use of solar power is very limited. Today we use very little active solar heating. Though in the future many more homes will be solar heated. More homes will have passive solar heating. Scientists want to make a satellite that will orbit over one place. This satellite would have giant wings made of solar power, this satellite would beam electricity down to earth. This would allow the solar cells not to be obstructed by clouds or buildings. Also ground solar power plants are predicted to be used more frequently. Another thing predicted to be popular is solar powered cars. The drawback of these cars is the fact that you can only travel at high speeds for a short time and they don’t work on cloudy days

As discussed above that the solar powered vehicles are used not quite widely because of the limitations or the drawbacks such as storage of energy, the climatic conditions are another factor that could be stated. We cannot predict how the nature would be in the next 24 hour window which is why we are not able to use the solar energy more efficiently and effectively. Similarly the issue of storage of solar energy is the most prominent one, even if we get good climatic conditions we need to store that absorbed energy into some mode most commonly used are high end batteries that can store the energy in the form of electricity in them but they also are not helping in more or to be precise much efficient usage of the solar energy

The Frontier Research Center at UNC-Chapel Hill has built a system that converts solar energy into fuel, so power can be used even after the sun sets.

Instead of storing solar electricity in an expensive battery, researchers use the sun's energy to separate water into hydrogen and oxygen.  Two of the Center's papers about the process were recently published in the Proceedings of the National Academy of Sciences.

That means only one percent of the solar power that reaches the device is currently used to convert water into fuel. Meyer says the process

wouldn't be viable on a commercial scale until technology reached about 10 percent efficiency, which could take a few decades.

Solar power is the conversion of sunlight into electricity, either directly using photovoltaics (PV), or indirectly using concentrated solar power (CSP). Concentrated solar power systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. Photovoltaics convert light into electric current using the photovoltaic effect.

Photovoltaics were initially, and still are, used to power small and medium-sized applications, from the calculator powered by a single solar cell to off-grid homes powered by a photovoltaic array. They are an important and relatively inexpensive source of electrical energy where grid power is inconvenient, unreasonably expensive to connect, or simply unavailable. However, as the cost of solar electricity is falling, solar power is also increasingly being used even in grid-connected situations as a way to feed low-carbon energy into the grid.

A solar power tower uses an array of tracking reflectors (heliostats) to concentrate light on a central receiver atop a tower. Power towers are

more cost effective, offer higher efficiency and better energy storage capability among CSP technologies. The PS10 Solar Power Plant and PS20 solar power plant are examples of this technology.

Solar Photovoltaic (SPV)SPV cells work by converting sunlight into electric current. An SPV cell is a semi-conductor system made of silicon or similar materials. The system generates electricity when it is exposed to sunlight. Power is generated by connecting thousands of tiny solar cells which forms modules.There are different types of solar PV cells based on the choice of materials used. Crystalline Silicon solar cells are of two types – polycrystalline and monocrystalline. Thin-film solar PV cells can be made of Amorphous Silicon, CdTe or CIGS.

Reasons for Choosing Solar Energy

It is possible to use solar energy for different types of applications. It can be used for both grid-connected and off-grid generation of power.

1. Solar energy for grid-connected electricityLarge scale grid-based solar energy is generated from CSP Plants and photovoltaic (PV) cells. The reasons for choosing grid-connection include the following:

• Day is the time of peak load demand and solar energy is easily available.

• Because the equipments involved in solar energy conversion and storage are relatively long-lasting and require lower maintenance, the energy infrastructure lasts longer.• Lower cost of running and ROI on grid-tie up.• Relative to traditional thermal power, solar energy produces clean energy without causing any pollution.• Availability of free solar power in every part of the world, and can be used almost anywhere.

2. Solar energy for off-gridSuch systems may or may not have a power storage facility in the form of batteries. Such remote power systems can be installed for many reasons. This includes the following:

• A desire to depend on renewable energy that is free from pollution and is safe for the environment.• A desire to combine different available options of power to create a hybrid source of power generation.• A desire for becoming independent from the inconsistent or fault ridden grid connection.• Availability of power storage systems like batteries.• Absence of overhead wires – elimination of power loss during transmission.• For use in different products and purposes like heating, cooking, lighting, communication equipments, pumping or in small scale industry.

Applications

1. Architecture and urban planningSunlight has influenced building design since the beginning of architectural history.[20] Advanced solar architecture and urban

planning methods were first employed by the Greeks and Chinese, who oriented their buildings toward the south to provide light and warmth.

2. Agriculture and horticultureAgriculture and horticulture seek to optimize the capture of solar energy in order to optimize the productivity of plants. Techniques such as timed planting cycles, tailored row orientation, staggered heights between rows and the mixing of plant varieties can improve crop yields

3. Transport and reconnaissanceDevelopment of a solar-powered car has been an engineering goal since the 1980s. The World Solar Challenge is a biannual solar-powered car race, where teams from universities and enterprises compete over 3,021 kilometres (1,877 mi) across central Australia from Darwin to Adelaide.

4. Solar thermalSolar thermal technologies can be used for water heating, space heating, space cooling and process heat generation.

5. CookingSolar cookers use sunlight for cooking, drying and pasteurization. They can be grouped into three broad categories: box cookers, panel cookers and reflector cookers.The simplest solar cooker is the box cooker first built by Horace de Saussure in 1767.

Advantages

1. Solar energy is a clean and renewable energy source.2. Once a solar panel is installed, solar energy can be produced free

of charge.3. Solar energy will last forever whereas it is estimated that the

world’s oil reserves will last for 30 to 40 years.4. Solar energy causes no pollution.5. Solar cells make absolutely no noise at all. On the other hand, the

giant machines utilized for pumping oil are extremely noisy and therefore very impractical.

6. Very little maintenance is needed to keep solar cells running. There are no moving parts in a solar cell which makes it impossible to really damage them.

7. In the long term, there can be a high return on investment due to the amount of free energy a solar panel can produce, it is estimated that the average household will see 50% of their energy coming in from solar panels.

Disadvantages

1. Solar panels can be expensive to install resulting in a time-lag of many years for savings on energy bills to match initial investments.

2. Electricity generation depends entirely on a countries exposure to sunlight; this could be limited by a countries climate.

3. Solar power stations do not match the power output of similar sized conventional power stations; they can also be very expensive to build.

4. Solar power is used to charge batteries so that solar powered devices can be used at night. The batteries can often be large and heavy, taking up space and needing to be replaced from time to time.

: SOLAR PANELA solar cell (also called a photovoltaic cell) is an electrical device that converts the energy of light directly into electricity by the photovoltaic effect its electrical characteristics, e.g. current, voltage, or resistance vary when light is incident upon it and can generate and support an electric current without being attached to any external voltage source. Inverter 2 years all India support warranty, Solar panel 25 years process warranty, Battery 3 Years manufactures warranty

Applications:

1) Solar cells are often electrically connected and encapsulated as a module.

Photovoltaic modules often have a sheet of glass on the front (sun up) side, allowing light to pass while protecting the semiconductor wafers from abrasion and impact due to wind-driven debris, rain, hail, etc.

2) Solar cells are also usually connected in series in modules, creating an additive voltage.

3) Connecting cells in parallel will yield a higher current shadow effects can shut down the weaker(less illuminated) parallel string (a number of series connected cells) causing substantial power loss and even damaging the weaker string because of the excessive reverse bias applied to the shadowed cells by their illuminated partners.

4) Practical use of the solar-generated energy, the electricity is most often fed into the electricity grid using inverters (grid-connected photovoltaic systems), in stand-alone systems, batteries are used to store the energy that is not needed immediately.

5) Solar panels can be used to power or recharge portable devices.

Major types:

1. Crystalline silicon: a) mono-crystalline

b) poly-crystalline

c) mono-like-multi silicon

2. Amorphous silicon

3. Cadmium telluride

4. Copper indium selenide/sulfide

5. Gallium arsenide multi junction

Mono-crystalline: Single-crystal wafer cells tend to be expensive, and because they are cut from cylindrical ingots.

Poly-crystalline: made from cast square ingots — large blocks of molten silicon carefully cooled and solidified .Poly-Si cells are less expensive to produce than single crystal silicon cells, but are less efficient.

Mono-like-multi silicon: uses existing polycrystalline casting chambers with small "seeds" of mono material. The result is a bulk mono-like material with poly around the outsides. It produces mono-like cells at poly-like prices.

cadmium telluride: uses a cadmium telluride (CdTe) thin film, lowest quoted thin-film module price stands at US$0.84 per watt-peak, with the lowest crystalline silicon (c-Si) module at $1.06 per watt-peak. The cadmium present in the cells would be toxic if released. However, release is impossible during normal operation of the cells and is unlikely during fires in residential roofs.

copper indium selenide: CIGS is a direct band gap material. It has the highest efficiency (~20%) among thin film materials.

Gallium arsenide multi junction: GaAs based multi junction devices are the most efficient solar cells to date. In October 15, 2012, triple junction metamorphic cell reached a record high of 44%.These multi junction cells consist of multiple thin films produced using metal organic vapor phase epitaxial. E.g. A triple-junction cell, for example, may consist of the semiconductors: GaAs, Ge, and GaInP2 .

Working:

The operation of a photovoltaic (PV) cell requires 3 basic attributes:

1. The absorption of light by semiconductor materials (like silicon), generating either electron-hole pairs or excitants.

2. The separation of charge carriers of opposite types.

3. The separate extraction of those carriers to an external circuit.

Efficiency:

Single p–n junction crystalline silicon devices are now approaching the theoretical limiting power efficiency of 33.7%.

Comparison between poly-crystalline and mono-crystalline:

1) Atomic arrangement:Mono-crystalline silicon (sc-Si) modules have ordered atomic structure while Poly-crystalline silicon (mc-Si) has more disordered atomic structure.

2) Efficiency:Mono-crystalline silicon (sc-Si) modules have higher conversion efficiency about 14% to 20% while poly-crystalline silicon (mc-Si) modules have lower efficiency about 11% to 15%.

3) Economic Cost:Poly-crystalline is less expensive than mono-crystalline silicon.

4) Degradation:Poly-crystalline silicon are more resistant to degradation (due to irradiation) while mono-crystalline are less.(The degradation rate is about 2 percent per year for multiple crystalline technologies).

Note: (some beneficial points why to prefer crystalline silicon)

Due to their proven and reliable technology, long life times and abundant primary resources. Their efficiency is expected to reach 21 percent in the long term.

Circuit diagram:

How to connect multiple solar panels:

fig. 9.h

As per our battery specification we need approx 25Ah current rating and 4*12V voltage rating so when charging the battery we connect 2-2 panels in series and combination to parallel as shown in diagram,

Now we got approx 36.68V voltage and 10.9A current which can charge our battery in approx 2 hrs 15 min

And when we have to run motor via panel we connect all the panels in parallel that will give approx 21.8A current and 18.34V voltage that will give 400W rating approx.

Specification:

Specification:

Model: SL100TU18P

Power: 100W

Voltage: 18.34V

Current: 5.45A

Efficiency: 14.12%

Power Tolerance: -3% to +3%

Operating Temperature: -40 to 85*C

Cost:

Quantity: 4 panelsTotal cost: Rs 12280 INR approx

New Nanoparticles to Make Solar Panels More Efficient and Cheaper

A new class of nanoparticles is capable of converting sunlight more efficiently into electricityeven when exposed to airThe researchers are very confident that these solid, stable, light-sensitive nanoparticles will help them create cheaper and more flexible solar cells. These nanoparticles are called colloidal quantum dots. The nanoparticles have a great potential to revolutionize the solar panel industry by offering more cost-efficient solar panels for homes and businesses.

Colloidal quantum dots can be used to create less expensive infrared light emitting diodes, infrared lasers, solar cellsand next-gen gas sensors.The study, published in Nature Materials this week, was led by Professor Ted Sargent and ZhijunNing.

"The field of colloidal quantum dot photovoltaics requires continued improvement in absolute performance, or power conversion efficiency. The field has moved fast, and keeps moving fast, but we need to work

toward bringing performance to commercially compelling levels", said Sargent.

The colloidal quantum dots can be effectively used to collect sunlight. All that is required to perform the task is two semiconductor types: p-types and n-types. The researchers endeavoured to layer the enhanced n-type colloidal quantum dots with the p-type. This made solar power conversion up to 8% more efficient.

Solar Panels : An eco-friendly electric generator.Solar panels generate free power from the sun by converting sunlight to electricity with no moving parts, zero emissions, and no maintenance. The solar panel, the first component of a electric solar energy system, is a collection of individual silicon cells that generate electricity from sunlight. The photons (light particles) produce an electrical current as they strike the surface of the thin silicon wafers. A single solar cell produces only about 1/2 (.5) of a volt. However, a typical 12 volt panel about 25 inches by 54 inches will contain 36 cells wired in series to produce about 17 volts peak output. If the solar panel can be configured for 24 volt output, there will be 72 cells so the two 12 volt groups of 36 each can be wired in series, usually with a jumper, allowing the solar panel to output 24 volts. When under load (charging batteries for example), this voltage drops to 12 to 14 volts (for a 12 volt configuration) resulting in 75 to 100 watts for a panel of this size.Multiple solar panels can be wired in parallel to increase current capacity (more power) and wired in series to increase voltage for 24, 48, or even higher voltage systems. The advantage of using a higher voltage output at the solar panels is that smaller wire sizes can be used to transfer the electric power from the solar panel array to the charge

controller & batteries. Since copper has gone up considerably in the last few years, purchasing large copper wiring and cables is quite expensive. (that's why pennies are made of mostly zinc today).

The 3 basic types of Solar PanelsMonocrystalline solar panels : The most efficient and expensive solar panels are made with Monocrystalline cells. These solar cells use very pure silicon and involve a complicated crystal growth process. Long silicon rods are produced which are cut into slices of .2 to .4 mm thick discs or wafers which are then processed into individual cells that are wired together in the solar panel.Polycrystalline solar panels : Often called Multi-crystalline, solar panels made with Polycrystalline cells are a little less expensive & slightly less efficient than Monocrystalline cells because the cells are not grown in single crystals but in a large block of many crystals. This is what gives them that striking shattered glass appearance. Like Monocrystalline cells, they are also then sliced into wafers to produce the individual cells that make up the solar panel.Amorphous solar panels : These are not really crystals, but a thin layer of silicon deposited on a base material such as metal or glass to create the solar panel. These Amorphous solar panels are much cheaper, but their energy efficiency is also much less so more square footage is required to produce the same amount of power as the Monocrystalline or Polycrystalline type of solar panel. Amorphous solar panels can even be made into long sheets of roofing material to cover large areas of a south facing roof surface.

Shading & Shadows on solar panelsWhen deciding on a location for your solar panels, make sure no shadows will fall on the solar panel array during peak sunlight hours (say, 9am to 4pm). Not only will shading of the solar panels significantly reduce their output, but also could cause damage. Some solar panel manufacturers advertise panels that can withstand shading but they use internal diodes which in themselves reduce the power somewhat. I recommend simply choosing a good location to start with, even if it means cutting down a few trees or otherwise removing obstacles.

Temperature & Wind loading considerationsAs previously discussed, you want to mount solar panels in a sunny and non-shaded location to get maximum sun. But, heat build-up is also a problem. Because the efficiency of solar panels decreases as temperature increases, the solar panel mounting system should allow for spacing around the individual solar panels for air circulation. The idea is to allow air cooling in the hot sun to reduce the temperature of the solar panels. Another consideration is wind loading. By allowing air to flow around the solar panels, not only will they remain cooler, but also the wind resistance of the entire array is less.

Types of Solar Panel Array Mountings : Fixed, Adjustable, & TrackingFixed solar panel mounts : If you use the most simple and least expensive type of solar panel mounting system, it will be completely stationary. The solar panels should always face the equator. (due south in the northern hemisphere). Don't forget that true south varies from magnetic south. This can make a huge difference. For example, true south in eastern Washington state is 161 on a compass instead of 180. The angle of inclination (tilt) in degrees

should be set to about your latitude. Slightly more than your latitude will favor the winter sun and slightly less will favor the summer sun. (for a seasonal cabin for example).

Adjustable solar panel mounts : The angle of inclination (tilt) of an adjustable solar panel mount can be changed 2 or more times during the year to account for the lower angle of the sun in winter as the earth orbits the sun causing seasonal change. A good rule of thumb is latitude + 15 degrees in the winter and latitude - 15 degrees in the summer. This will increase overall solar panel output by approximately 25%. I adjust my solar panel array 4 times per year. (Shown here in its summer position). An easy approach that works pretty good is to set the tilt for the winter position in about mid October and back to summer position in mid March.

Tracking solar panel mounts : Tracking solar panel mounts follow the path of the sun during the day to maximize the solar radiation that the solar panels receive. A single axis tracker tracks the sun east to west and a two-axis tracker tracks the daily east to west movement of the sun and the seasonal declination movement of the sun.I must admit that a tracking type of solar panel mount is the most efficient type. However, when I investigated the cost for these mounting systems, I found that for the 20 to 30 percent gain in output they provided I could buy 25% more panels cheaper and have the same increase in power with no mechanical failures to worry about. Also, you'll get far less extra gain in winter assuming it doesn't freeze up!Therefore, I recommend that instead of 6 panels on a tracking mount that costs $2000-$3000, just spend $700-$800 on 2 more solar panels and

gain a year round increase of 25 to 30%. Simple math, huh?

How much sunshine will I need?For more detailed information on how many solar panels you will need based on the amount of sunshine available daily in your area (of the United States) please check out the advanced tutorial Solar Radiation. This will give you a better idea of how many solar panels you will need for your solar power system.

Cost and expected LifeSpan of solar panelsAt today's prices a single solar panel, rated at 75-85 watts sells for about $375-$425 depending on brand. I have found that the brand does not seem to be a huge factor. If your system uses several of these panels, this would seem to be quite expensive. The good news is that today's solar panels have a life expectancy of 25 to 30 years or more. And just think, they'll be making FREE electricity that whole time!

SummaryAt today's prices, a typical 100 watt solar panel will cost about $400 to $500 or about $4 to $5 per watt. With a total of only six 80 Watt solar panels this Solar Home runs a refrigerator, computer, 27 inch color tv, microwave, various lights, misc devices, and even an Air Conditioner in the summer. Only for about 2 to 3 months in the winter (at 45 degrees north) is a generator used for 45 to 60 minutes per day to bulk charge the batteries. Since some winter days are sunny, the generator is not used every day.

A new material for solar panels could make them cheaper, more efficient

A unique solar panel design made with a new ceramic material points the way to potentially providing sustainable power cheaper, more efficiently, and requiring less manufacturing time. It also reaches a four-decade-old goal of discovering a bulk photovoltaic material that can harness energy from visible and infrared light, not just ultraviolet light.

Scaling up this new design from its tablet-size prototype to a full-size solar panel would be a large step toward making solar power affordable compared with other means of producing electricity. It would also help the nation toward its goal of creating a national power grid that receives one-third of its power through wind and solar sources.

Part of the reason solar panels have low efficiency is that the particles collected from the sun enter the solar cell and spread out in all directions. Getting them all to flow one direction typically requires

layers of different channeling material. Each time the particles pass between these layers some get lost, decreasing the energy efficiency of the solar cell. The team’s new design uses fewer layers to limit loss and uses ferroelectric material to use up less energy channeling the particles.

It took more than five years to model and design a material with this combination of properties. The material uses perovskite crystals made with a combination of potassium niobate and barium nickel niobate. It has shown significant improvement over today’s classic ferroelectric material. The new material can absorb six times more energy and transfer a photocurrent 50 times denser. Further tuning of the material’s composition should expand efficiency, the scientists say.

By adjusting the percentages of component elements in this new material, the research team demonstrated that they can reduce the amount of energy needed to induce conduction, a level called bandgap.

“The parent material’s bandgap is in the UV range,” Spanier said, “but adding just 10 percent of the barium nickel niobate moves the bandgap into the visible range and close to the desired value for efficient solar-energy

The first component needed is one or more Solar Panels. They supply the electricity and charge the batteries. A very small system could get away with a couple 80 watt panels but figure at least 4 to 8 for a small to medium system. I am currently using only 6 panels to completely power this Solar Home.

Charge Controller. is needed to prevent overcharging of the batteries. Proper charging will prevent damage and increase the life and performance of the batteries.

is the heart of the system. It makes 120 volts AC from the 12 volts DC stored in the batteries. It can also charge the batteries if connected to a generator or the AC

Last are the storage Batteries. They store the electrical power in the form of a chemical reaction. Without storage you would only have power when the sun was shining or the generator was running.

SummaryTo summarize, there are four basic components: the Solar Panels, a Charge Controller, a Power Inverter, and the Storage Batteries. You will of course need the proper wires & cables to connect everything and a meter to keep an eye on things would be nice. Depending on system size, costs vary widely from as little as $1,500 to $50,000 or more. Much more information is available in the remaining tutorials. For more detailed information also view

section. And don't miss our new interactive Design Tools.

This small energy efficient home uses six 80 watt solar panels, a Trace 60 amp charge controller, a Trace 2500 watt true sine wave inverter and fifteen 105 AmpHour batteries. Click on the image for details and new updated pictures of Solar array. (Trace is now Xantrex)

This will include the Solar Panels which generate the electricity, the Charge Controller to control battery charging, Power Inverter that makes 120 volts AC from the batteries to run your appliances, the storage batteries

store the excess power for use when the sun is weak or not available, and AC generators for back-up power. We will also discuss the proper wire sizes used to connect the components together and meters & monitorssystem performance and usage.

Efficiency is an important parameter of PV modules. Module efficiency shows what part of the solar energy fallen onto the module’s surface is converted into electrical power.

Every PV module has its rated power or peak power, denoted in kWp.

The peak power of the module however is not the real power the module can generate.

The real power output of the module is always less than the rated power, due to the following factors:

Manufacturer power toleranceDirt and dustTemperatureCable lossesInverter efficiencyShading

Manufacturer power tolerance is the percentage within which the manufacturers guarantee that the real power output will be the same as the rated power output. Such percentage is never 100, the typical value is 95, since PV

modules operate in an environment different than Standard Test Conditions.

Dirt and dust cause losses when accumulated on the surface of a photovoltaic module. Dirt and dust particles could block the sunlight and thus reduce the power output. The content of dirt and dust in the air may vary with location and is usually the highest in urban environment. Certainly in regions with heavy rainfall dirt losses tend to

Inverter efficiency denotes what part of the input DC power is converted into AC power. The percentage is never 100, but values of inverter efficiency between 90% and 95% are widely assumed in practice.

 must be avoided since even small shadows could severely reduce the performance of a PV module. A PV module consists of cells, and when gets shaded, any cell turns into a heat-dissipating resistor boosting dramatically the temperature of the PV module. This results not only in unexpected reduction of the output voltage, but also in shortening the life cycle of cells and modules. When mounted on the roof, PV modules could easily underperform due to shading caused by trees, chimneys and other roof protrusions that can hard to eliminate.

Temperature is one of the most important factors to be considered when designing a PV system. Temperature influences all the three main electrical parameters of a PV module – voltage, current and power. When the weather gets warmer, the output voltage goes down and visa versa – when the weather gets colder, voltage goes up. Things are different with power – when temperature goes up, output power increases too.

Charge ControllersNext, read the Charge Controller tutorial to see why this device is necessary to protect the batteries from over charging and supply them with the proper amount of energy to promote long battery life. The popular 3 stage charging cycle of PWM charge controllers is fully explained and shown visually on a multi-color chart.   <details>

Power Inverters

The Power Inverter tutorial will cover the 3 basic types of power inverters so you can decide which one is right for you. The power inverter converts your storage battery power into the 120 volts AC that runs your appliances. It is the heart of your solar energy system. Unless you only run 12 volt DC appliances you will need a power inverter to supply your AC.   <details>

Storage BatteriesWithout Storage Batteries to store energy you would only have power when the sun was shining or the generator was running. Here we discuss 4 major categories of batteries for solar power systems. The batteries in your system are very important. The care & feeding section of this tutorial is a must read to ensure long battery life and good performance.    <details>

AC GeneratorsEven the largest Solar Energy System would not have enough power for many consecutive days of no sun. The AC Generator tutorial will tell you what size generator you'll need and the best techniques to use when charging your batteries and/or supplying power to extra large appliances.    <details>

Wires & CablesTo prevent dangerous overheating or inefficient tranfer of power, the wires and cables in a solar power system must be correctly sized. This tutorial provides a convenient chart to determine wire size based on solar panel power output and the distance between the solar panels and the batteries. For safety and good performance of your solar power system you will have to use the appropriate size wires when connecting the components of your system.   <details>

Meters & MonitorsThis tutorial explains the importance of monitoring your solar energy system. With the included voltage chart, you can easily determine the basic level of charge on your batteries using just a simple voltmeter. Taking proper care of your batteries will ensure good system performance.    <details>

Battery Wiring DiagramsLearn how to use series and parallel wiring techniques to obtain exactly the power and voltage you want using 2, 4, 6, or 12 volt batteries. Series wiring, parallel wiring and using series/parallel combinations show you how to build your battery bank into any configuration you need using simple pictorial diagrams.    <details>

Solar Radiation : Sunshine across the United StatesThis tutorial shows a color coded map of the United States that displays the daily average hours of solar radiation (sunshine). This information will assist you in calculating the number of solar panels you will need for your solar power system. Also included in this tutorial is a short explanation of Watts, WattHours, and AmpHours and how they are used.   <details>

Putting it all togetherTake a look at a simple animation of all these components working together. This will give you an overview of the minimum equipment needed for a solar alternative energy system.    <details>

Design your system quickly with our Interactive Design Tools

(Note : These design tools require javascript to be turned on in your browser)

Check out our easy point & click System Sizing Estimator to quickly & easily calculate the number of solar panels and storage batteries you'll need for a wide range of system sizes.

Battery Bank Design Tool will take the confusion out of wiring up your battery bank. Use 2, 4, 6, or 12 volt batteries to build a system voltage of 12, 24, or 48 volts using series and parallel wiring with just 4 clicks. Battery bank capacities from 300 AmpHours to over 4000 AmpHours are displayed graphically so you can see exactly how to wire the batteries together.

Wire Size Calculator will allow you to quickly find the correct wire size in AWG (American Wire Gauge) based on the distance to your solar panel array & the amount of amperage your panels put out. No math required!

The Power Inverter

Unless you plan on using battery power for everything, you will need a Power Inverter. Since the majority of modern conveniences all run on 120 volts AC, the Power Inverter will be the heart of your Solar Energy System. It not only converts the low voltage DC to the 120 volts AC that runs most appliances, but also can charge the batteries if connected to the utility grid or a AC Generator as in the case of a totally independent stand-alone solar power system.

Square Wave power inverters :This is the least expensive and least desirable type. The square wave it produces is inefficient and is hard on many types of equipment. These inverters are usually fairly inexpensive, 500 watts or less, and use an automotive cigarette lighter plug-in. Don't even consider one of these types of power inverters for a home system.

Modified Sine Wave power inverters :This is probably the most popular and economical type of power inverter. It produces an AC waveform somewhere between a square wave and a pure sine wave. Modified Sine Wave inverters, sometimes called Quasi-Sine Wave inverters are not real expensive and work well in all but the most demanding applications and even most computers work well with a Modified Sine Wave inverter. However, there

are exceptions. Some appliances that use motor speed controls or that use timers may not work quite right with a Modified Sine Wave inverter. And since more and more consumer products are using speed controls & timers, I would only recommend this type of inverter for smaller installations such as a camping cabin.

True Sine Wave power inverters :A True Sine Wave power inverter produces the closest to a pure sine wave of all power inverters and in many cases produces cleaner power than the utility company itself. It will run practically any type of AC equipment and is also the most expensive. Many True Sine Wave power inverters are computer controlled and will automatically turn on and off as AC loads ask for service. I believe they are well worth the extra cost. I use a True Sine Wave power inverter myself and find that its automatic capabilities makes it seem more like Utility Company power. The Xantrex 2500 watt power inverter I use has a search feature and checks every couple of seconds for anything that wants AC, then it powers up automatically. You just flick on a light switch (or whatever) and it works. When you turn off the light or the refrigerator kicks off for example, the power inverter shuts down to save battery power.While the Modified Sine Wave inverter (sometimes called a Quasi Sine Wave inverter) is nearly half the price of a True Sine Wave inverter, I would still recommend using a True Sine Wave inverter if you want to supply automatic power to a normal home using a wide variety of electrical devices. Also, most appliances run more efficiently and use less power with a True Sine Wave inverter as opposed to a Modified Sine Wave power inverter.

Grid Tie Power InvertersIf you are connected to normal Utility company power and just want to add some Free Sun Power electricity to reduce your electric bill and you do not need a totally independent system, it is possible that a Grid Tie power inverter will suit your needs. With a Grid Tie power inverter, whatever electricity that your solar panels produce will reduce the amount supplied by the utility company, in effect lowering your bill. And, if you are producing more power than you are using, you can actually sell the extra power back to the utility company! For this type of setup a much smaller battery bank can be installed just to cover short term outages from a few minutes to an hour or two. In fact, if you don't have frequent long term power outages and don't need back-up power, then you will not need any batteries at all. (But, really, what utility company never fails? :)

Input voltages. Should I use a 12, 24, or 48 volt inverter?The main consideration when deciding on the input voltage (from your battery bank) of your Inverter is the distance between your solar panel array and your battery bank. The higher the voltage, the lower the current and the smaller the (expensive) cables need to be. Of course, when you decide on a system voltage, the Solar Panels, Inverter, and Battery Bank all need to use the same voltage. More detailed information on voltage & current is explained in the tutorial on Power & Watts.To help decide on which voltage to use, check out our Wire Size Calculator which can tell you what size wire is needed to connect the solar panels to your equipment area. You can try all 3 different voltages to see the change that it can make in wire size.

Inverter Stacking: Using multiple inverters.Two inverters can be installed in a configuration known as stacking that can provide more power or higher voltage. If two compatible

inverters are stacked in series you can double the output voltage. This would be the technique to use to provide 120/240 volts AC. On the other hand, if you configure them in parallel, you can double your power. Two 4000 watt inverters in parallel would give you 8000 watts (8KW) of electricity

Power Inverter considerationsThe Power Inverter is connected directly to the batteries and the main AC breaker panel to supply power from the batteries to the loads (appliances). Check out Wires & Cables for more info on the necessary wire size for installing one or use our new Wire Size CalculatorThe Power Inverter converts the low voltage DC to 120 volts AC. Power Inverters are available for use on 12, 24, or 48 volt battery bank configurations. Most Power Inverters can also charge the batteries if connected to the AC line. Alternatively, the AC line input could be your own AC Generator in the case of a stand-alone solar power system. When using a AC Generator to charge the batteries, the Power Inverter transfers the AC Generator power to the loads via a relay. This way the AC Generator not only charges the batteries but also supplies your AC power while it is running. If your Generator is at least 5000 watts, you can charge your batteries and have extra AC power at the same time.

How can I determine how many solar panels and batteries I'll need?This will depend on how much electricity you are going to need and how many days you plan to be able to run on just battery power alone (no sun at all). To assist you in determining the size system you will need, our  System Sizing Estimator   will help you calculate the number of solar panels you'll need and what size battery bank is required. We also provide a Battery Bank Designer tool to show you how to wire your battery bank for a 12, 24, or 48 volt system.

What kind of wires or cables will I need to hook all this stuff together?Wires & Cables tutorial covers this question and provides a handy chart to calculate the required wire sizes based on the voltage of

your system and the distances between components. Also, our new Wire Size Calculator tool will calculate wires sizes for you.

Summary

For a small system on a budget, a 2000 to 3000 watt Modified Sine Wave power inverter will do the job for around $1200 to $1500. Expect to pay up to $1000 more for a True Sine Wave power inverter if you want to be able to run anything and have the automatic features. These higher quality Power Inverters are computer controlled and once set-up, can control your 120 volts AC, battery charging, and even auto-start compatible AC Generators; all automatically.

If your goal is to provide real home power, A True Sine Wave inverter is really your best choice. The extra cost, in the long run, is a good investment in performance and reliability. For a small seasonal use cabin, a Modified Sine Wave inverter would probably do the

Why a Charge Controller is necessarySince the brighter the sunlight, the more voltage the solar cells produce, the excessive voltage could damage the batteries. A charge controller is used to maintain the proper charging voltage on the batteries. As the input voltage from the solar arrayrises, the charge controller regulates the charge to the batteries preventing any over charging.

Modern multi-stage charge controllersMost quality charge controller units have what is known as a 3 stage charge cycle that goes like this :

BULK :  During the Bulk phase of the charge cycle, the voltage gradually rises to the Bulk level (usually 14.4 to 14.6 volts) while the batteries draw maximum current. When Bulk level voltage is reached the absorption stage begins.

ABSORPTION :  During this phase the voltage is maintained at Bulk voltage level for a specified time (usually an hour) while the current gradually tapers off as the batteries charge up.

FLOAT :  After the absorption time passes the voltage is lowered to float level (usually 13.4 to 13.7 volts) and the batteries draw a small maintenance current until the next cycle.

The relationship between the current and the voltage during the 3 phases of the charge cycle can be shown visually by the graph below.

MPPT Maximum Power Point TrackingMost multi-stage charge controllers are Pulse Width Modulation (PWM) types. I would recommend using one of at least this design. The newer Maximum Power Point Tracking (MPPT) controllers are even better. They match the output of the solar panels to the battery voltage to insure maximum charge (amps). For example: even though your solar panel is rated at 100 watts, you won't get the full 100 watts unless the battery is at optimum voltage. The Power/Watts is always equal to Volts times Amps or P=E*I (see Ohm's law for more info). With a regular charge controller, if your batteries are low at say 12.4 volts, then your 100 watt solar panel rated at 6 amps at 16.5 volts (6 amps times 16.5 volts = 100 watts) will only charge at 6 amps times 12.4 volts or just 75 watts. You just lost 25% of your capacity! The MPPT controller compensates for the lower battery voltage by delivering closer to 8 amps into the 12.4 volt battery maintaining the full power of the 100 watt solar panel! 100 watts = 12.4 volts times 8 amps = 100 (P=E*I).

The Charge Controller is installed between the Solar Panel array and the Batteries where it automatically maintains the charge on the batteries using the 3 stage charge cycle just decribed. The Power Inverter can also charge the batteries if it is connected to the AC utility grid or in the case of a stand alone system, your own AC Generator

SummaryIf you are using four 75 to 80 Watt solar panels, your charge controller should be rated up to 40 amps. Even though the solar panels don't normally produce that much current, there is an 'edge of cloud effect'. Due to this phenomenon I have seen my four 6 amp panels (4*6=24) pump out over 32 amps. This is well over their rated 24 amps maximum. A good 3 stage 40 amp Charge Controller will run about $140 to $225 depending on features like LCD displays. For eight 75 to 80 watt solar panels you would need two 40 amp Charge Controllers to handle the power or you could increase your system voltage to 24 volts and still use just one 40 amp Charge Controller. Check

Battery Wiring Diagrams for details on how to set-up your system voltage and see the actual wiring diagrams you need with our Battery Bank Designer which will display the required wiring with just 4 clicks!".

Correct wire sizes are essential

To connect the components of a Solar Energy System, you will need to use correct wire sizes to ensure low loss of energy and to prevent overheating and possible damage or even fire. Below is a chart showing the required wire size for wire lengths to connect the solar panels to theCharge Controller. Use these numbers for a 12 volt system to achieve a 3% or less voltage drop.

The top row represents the Wire gauge size, the left column the number of amps the solar panels are rated at, and the grid cells show the distances in feet between the Solar Panels and the Charge Controller.

For example: If you have 3 solar panels rated at 6 amps each, mounted 30 feet from the Charge Controller, then you would move down the chart to 18 amps (3 panels * 6 amps), and across to 32.5 (closest to 30), and then up the chart to #4. You would need at least #4 gauge wire (awg) to move 18 amps 30 feet with a minimum voltage drop of 3% or less, an acceptable loss.

If you can't find the exact numbers, choose either a larger gauge wire (smaller number) or select a distance longer than your actual distance.

Wire chart for connecting 12 Volt solar panels to the Charge ControllerThis chart shows wire distances for a 3% voltage drop or less. These distances are calculated for a 12 volt system. Multiply distances by 2 for a 24 volt system. Multiply distances by 4 for a 48 volt system.

: This chart is an approximate distance reference and is a little conservative. For a much more accurate wire sizing, use our new Wire Size Calculator tool. It can calculate wire size using 3%, 4%, or 5% losses plus you can select 12, 24, or 48 volt systems.

#12 #10 #8 #6 #4 #3 #2 #1 #1/0 #2/0

4 22.7 36.3 57.8 91.6 146 184 232 292 369 465

6 15.2 24.2 38.6 61.1 97.4 122 155 195 246 310

8 11.4 18.2 28.9 45.8 73.1 91.8 116 146 184 233

10 9.1 14.5 23.1 36.7 58.4 73.5 92.8 117 148 186

12 7.6 12.1 19.3 30.6 48.7 61.2 77.3 97.4 123 155

14 6.5 10.4 16.5 26.2 41.7 52.5 66.3 83.5 105 133

16 5.7 9.1 14.5 22.9 36.5 45.9 58.0 73.0 92.0 116

18 5.1 8.1 12.9 20.4 32.5 40.8 51.6 64.9 81.9 103

20 4.6 7.3 11.6 18.3 29.2 36.7 46.4 58.4 73.8 93.1

25 3.6 5.8 9.3 14.7 23.4 29.4 37.1 46.8 59.1 74.5

30 3.1 4.8 7.7 12.2 19.5 24.5 30.9 38.9 49.2 62.1

35 2.6 4.2 6.6 10.5 16.7 20.9 26.5 33.4 42.2 53.2

40 2.3 3.6 5.8 9.2 14.6 18.4 23.2 29.2 36.9 46.5

Connecting the Charge ControllerAfter you connect the Solar Panels to the input terminals of the Charge Controller using the above chart, you can use the same size wire to connect the Charge Controller output to the batteries since these wires will carry no more current than the solar panel wires and will probably be located pretty close to the batteries anyway.

Connecting the Power InverterPower Inverter is next. Both the Power Inverter and the Batteries require the largest wires in the system.

During operation, the AC produced by the Power Inverter draws considerable amps from the batteries. Not only are very large wires required, but they should not exceed 6 feet in length to reach the batteries. These wires are like the large battery cables in cars. Use the largest size possible. An AC appliance drawing 10 amps (like a microwave or vacuum cleaner) will require 100 amps at 12 volts DC. Even large cables will get warm. Don't skimp here.

Connecting the Batteries

The batteries are last. They will also require very large cables like the large battery cables in cars. The full current to the loads and also the full charging current flow thru the entire battery bank. Connect all the batteries with large high quality cables. Check out

Battery Wiring Diagrams tutorial for examples of Series and Parallel wiring techniques that allow the use of battery voltages of 2, 4, 6, or 12 volts. Our newBattery Bank Designer tool will show you how to connect the batteries for these various voltage

What is the Cost of Using Solar Energy

MARCH 15, 2014 BY SOLAR GUY  /

English: solar PV – Second largest Array in UK (Photo credit: Wikipedia)

A techno-economic assessment will prove the economic feasibility and sense of buying a solar electric system.

First, let’s consider grid-tied systems.

If you are planning to buy, build yourself or have built a grid-tied system, such an evaluation should by all means take into account expected future price of grid electricity over the period of the guaranteed solar system lifecycle, along with any potential income from other existing investment options.

The evaluation of a grid-tied system will provide you with enough data to compare the overall net income of your investment in solar PV system with other existing alternative options to invest your money taking into account:

price of solar hardware installation costs annual operational expenses generated ‘free’ solar energy offsetting these expenses.

By assessing how much money you can save from solar electricity you can take an informed decision whether it is worth investing in solar electricity or your money would be better invested in other financial

instruments, i.e. bank accounts or other possible investment options you can find at your disposal.

First of all, by performing a techno-economic assessment, you are going to find out:

What is the cost of using solar energy How to calculate total solar power you need to use and install How to determine how much area you need to install your PV

modules and which type of PV modules to choose taking into account:

Your solar installation area Various types of modules available on the market Your budget

Once you have chosen your type of PV module, you will find out how to calculate how many PV modules you need to install and the overall cost of your solar system.

Then you are going to find out:

How to calculate your solar energy production costs How much you can save by a PV system over its guaranteed life

cycle The payback period of your system.

If your stand-alone system contains an inverter, it should be replaced after 12-15 years of operation. So, if a stand-alone system has a lifespan of 25 years, the cost for inverter replacement should be included in the maintenance cost.

If we assume inverter cost of $1 per watt, based on the needed inverter with 840 W rated continuous power, the inverter will cost:

840 W x $1/W = $840.

Such a price distributed over 25 years of operation will result in average inverter maintenance costs per year as follows:

$840 ? 25 years = $33.6 or about $34.

More important however are battery maintenance costs.

A lead-acid battery is to be replaced after every 5 years of operation. At the moment a typical battery price is $1 per Ah.

So, the task is to calculate the costs for batteries during the stand-alone system’s lifecycle.

We assume that the battery cost for the first 5 years is included in the system cost.

If battery cost of $1 per Ah is assumed, for the next 25 year of the system lifecycle the costs for a battery bank of 470 Ah would be:

470 Ah x (25 years x 5) x $1/Ah = $2,350.

Such a cost distributed over 25 years of operation will result in the following average battery maintenance costs per year:

$2,350 x 25 years = $94.

Furthermore we could assume an MPPT charge controller with estimated price of $700.

MPPT charge controllers come with a typical warranty of 5 years. We could assume that you would need at least one additional charge controller for replacement.

Hence, the price of the additional MPPT charge controller average annual maintenance costs would be:

$700 x 25 years = $28

The total average annual maintenance cost of an off-grid system comprising a battery, an inverter and a MPPT charge controller would be:

Total average annual maintenance costs =

= Average annual inverter maintenance costs + Average annual charge controller maintenance cost + Average annual battery maintenance costs = $34 + $94 + $28 = $156

 Solar panels are the main building units of solar electric systems. To find out whether solar panels would save you money means to estimate your investment in a solar electric system.

Such a task starts with calculating solar electricity production costs.

It is important to calculate the cost of electricity produced by your PV system. After estimating the cost you can decide whether it is worth purchasing a solar system or not.

You could arrive at approximate estimate of hardware cost of your equipment by taking available prices on solar power equipment on internet.

No one however could tell you the exact prices of installation cost except your potential local installer. Have in mind that installation cost are about up to 30-50 % of overall system cost and one varies by location.

How to evaluate your system correctly with included installation cost?

The best approach is:

Step 1: Decide what type of system you are going to buy /grid-tied, grid-tied with battery backup, etc.).

Step 2: Contact your potential installers and to ask them for expected overall cost per Watt for the system type you have chosen.

Step 3: Multiply expected overall cost per Watt installed ($/Wp) by system size in Watt installed (Wp). Thus you calculate total system cost without operational expenses for the system’s period of operation (system lifespan).

Example:You want to buy a 4.5 kWp grid-tied system without battery backup. An installer has informed you that the expected price is $5 per Watt-peak. The final price is: $5 x 4,500Wp = $22,500.

 Step 4: Add the operational costs to the already calculated system cost.

If a solar system contains an inverter (every grid-tied system contains an inverter), you should consider its replacement after every 12-15 years of operation. In such a case, add $3,000 to the sum.

Step 5: Calculate solar electricity production.

Step 6: Use the formula given below to estimate solar electricity production costs over solar system lifespan.

Solar electricity production costs =

[Solar system initial cost + (System lifespan * Operating costs per year)] /(Annual solar electricity production *System lifespan)

 Solar system initial cost, a.k.a. CapEx, is the costs for implementing the whole system, including site survey, system design, construction works, obtaining permits, equipment delivery and installation, and system commissioning.

System lifespan is assumed 25 years. Operating costs, a.k.a. OpEx per year, are system maintenance

costs. The most essential part of the operating costs is related to inverter replacement. During a 25-year lifecycle the inverter should be replaced at least once. If the inverter costs $3,000, for a period of 25 years average annual maintenance costs would be

$3,000 / 25 years = $120 per year.

If the annual energy target is 7,000 kWh, then the daily energy target is:

7,000 kWh /365 days = 19.2 kWh

Upon daily average annual value of PSH is 5.5, and system efficiency is 0.7, the required installed solar power on the roof is:

 Installed solar power in kWp =

= Daily energy target in kWh /(PSH * System efficiency) =

= 19.2 /( 5.5 * 0.7) = 5.0 kWp = 5,000 Wp

If system implementation cost is estimated $5 per Wp and the installed solar power is 5 kWp, initial system cost is:

$5/Wp x 5,000 Wp = $25,000

Furthermore if:

System lifespan is 25 years, Yearly generated energy is 7,000 kWh under existing environmental

conditions, and OpEx is $120 per year (inverter is planned to be replaced once

during the system lifecycle, assumed cost for replacement is $3,000, and distributing this amount over a 25-year period gives $3,000 /25 years = $120 per year),

then solar electricity production costs over the total operational period of PV system [German Energy Society, 2008, pp. 333-334] are calculated as follows:

Solar electricity production costs =

= [Solar system initial cost + (System lifespan * Operating costs per year)] / (Annual solar electricity production * System lifespan) = [$25,000 + (25 years * $120)] /(7,000 kWh *25 years) =

= $0.16/kWh

So, 16 cents is the average price of electricity produced by this grid-tied PV system for a period of 25 years. These $0.16/kWh result into annual costs incurred by solar electricity generated by PV system as follows:

         Annual costs incurred by solar generated electricity=

= Annual solar electricity production * Solar electricity production costs = 365 x 19.2 kWh * $0.16/kWh =$1,121.28

If grid electricity price is $0.07/kWh, and we assume 5% increase of the electricity price per year (average increase rate during the last 30 years in the USA), the average electricity price you would pay for the same

amount of power to obtain from the electricity grid over 25 years will be $0.14/kWh, or a total of $24,500 payable to the grid:

Annual energy output * Period of system operation *Average grid electricity price within system operation period = 7,000 kWh * 25 * 0.14 $/kWh = $24,500 spent on grid electricity

In this case, after comparing the amount of $24,500 spent for electricity bill over a period of 25 years to the PV system initial cost of $25,000, buying a solar system is obviously not a good investment!

However if current electricity price is $0.10/kWh, under the very same conditions the average electricity price over a period of 25 years is calculated $0.20/kWh which translates into $36,750 to be paid by you to the grid.

If you compare this $36,750 to the initial investment of $25,000, the situation looks different, even taking into account the amount of $3,000 for inverter replacement in the twelfth year of system operation.

You should also mind that it is possible the price of the chosen type of inverter after 12-15 years of operation to be way less than the price at the moment of system launch.

Let’s go on with a more specific example.

If current electricity price is 20 cents per kWh (the price in the city of Los Angeles), the corresponding results are:

$0.40/kWh average electricity price for 25 year period $0.68/kWh electricity price at the end of 25 year period $2,803.2 paid annually to the grid if you would stay connected to

grid (that is 365 x 19.2 kWh x $0.40 = $2,803.2). These are annual

grid electricity cost savings, which are actually potential expenses payable to the grid if you did not have a solar electric system.

$70,080 paid by you to the grid over 25 year period upon 5% annual increase rate of the grid electricity price

You save on electricity bills a total of:           $70,080 (total money paid) – $25,000 (initial system cost) - 

           3,000 (System life span x Operating costs per year) = $42,080

The payback period of the system considering the forecast grid electricity price rise within a 25 year period would be:

      [PV system initial cost + (System life span x Operating costs per  

      year)] * Annual grid electricity cost savings =

      = [$25,000 + (25 years x $120)] * $2,803.2 = 10 years

In such a case buying a solar system is a very good investment, provided you do not have a better option to invest your $25,000.

Investing in a grid-tied PV system could save you more money than putting $25,000 in a bank for 25 years at 3.1% annually compound interest rate – you get as much as $28,629 additionally from interest rate over 25 years!

As a homeowner however, you are eligible to receive 30% off the total cost of your photovoltaic system from the federal government in the form of a Federal Solar Tax Credit. So actually you will pay for this system not $25,000 but $17,500 instead.

If you put this $17,500 in a bank, all you can get upon 3.1% of annual compound interest rate for 25 years is even less – $20,040!

You have noticed that no Feed-In Tariffs are included and discussed here. With Feed-In Tariffs things become even more attractive.

To learn about Feed-In Tariffs and other financial incentives, read on!

To have Feed-In Tariffs included in calculations, you should use our Gold Package calculator. Click Here to Learn More about our Solar Packages and Solar Gold Package Calculator.

If the provided here method for estimating feasibility of your investment in solar energy looks kind of cumbersome, you can use our handy, simple and fast Gold Package calculator for advanced evaluation of grid-tied solar systems without power backup.Click Here to Learn More

How Many Solar Panels Do I Need?

MAY 18, 2013 BY SOLAR GUY  /

A photovoltaic (PV) module that is composed of multiple PV cells. Two or more interconnected PV modules create an array. (Photo credit:

Wikipedia)

How many solar panels do I need is one of the most frequently asked questions by solar enthusiast. Let’s go straight to the point.

First, you should calculate your daily energy target.

You have to decide what percentage of your annual electricity bill you want to offset to your grid tied system.

Let’s say your annual energy usage is 7,000 kWh. You want to offset 40% of it to a grid-tied system.

This means that energy target is:

7,000 kWh x 0.40 = 2,800 kWh

Since there are 365 days in a year, your daily energy target is:

2,800 / 365 = 7.7 kWh

If you know your daily energy target and the average annual PSH (Perfect Sun Hours) value for your area, you can calculate the amount of peak power you need to install on your roof:

Installed ‘peak’ solar power = Daily energy target/(SLF*PSH)

SLF is the System Losses Factor, a.k.a system efficiency ,which takes into account  system losses or system inefficiency. For a grid-tied system system efficiency  is assessed usually between 70% and 80%. This means that we lose (20-30)% of the energy  in the system and our panels must have  higher installed peak power so as to compensate for those loses.For an off-grid system the system efficiency is  somewhere between (50-60)%.

If your daily energy target is in Wh, then you obtain the peak solar power in Wp (watts-peak). If daily energy target is in kWh, you obtain the peak solar power in kWp (kilowatts-peak).

PSH is abbreviated from ‘Perfect Sun Hours’ and refers to the number of hours per day during which the solar irradiance equals 1,000 W/m2. PSH are measured in kW/m2/day and it can be found by using solar maps.

If your daily energy target offset is 7.7 kWh, the area you live has an average annual PSH = 4.5 hours, and you assume system efficiency = 75% 0r SLF= 0.75, then the needed total peak installed power is:7.7 kWh / (4.5 hours x 0.75) = 2.28 kWp or

This is the installed ‘peak’ solar power needed to generate the required energy target.

At this stage it is important to assess how much area you need to install the solar array. Based on your energy needs, you can determine whether the area of your roof would be enough to fit all the panels needed. Here we don’t talk about a specific panel model but rather about solar panel type – monocrystalline, polycrystalline or thin-film.

The area required for installing the solar array, so that your PV system would meet the energy offset target, depends on:

Peak power installed on the roof (in kWp or Wp) The kind of modules you use (monocrystalline, polycrystalline,

thin-film).To estimate the area you need to install the required peak power, you should use the following table:

How to estimate the area you need to install the required solar peak power

The required roof area is calculated by the formula:

  Total area needed =

  = Installed solar power in kWp x Area needed for 1 kWp

a) If your target peak power is 2.28 kWp, and you decide to use monocrystalline solar modules, the area you need is:

   2.28 kWp x 7 m2 = 15.96 m2 or 2.28 kWp x 75 ft2 = 171 ft2

b) In case you prefer to use polycrystalline solar modules, the area you need is:

  2.28 kWp x 8 m2 = 18.24 m2 or 2.28 kWp x 86 ft2 = 196.08 ft2

c) Should you decide to buy thin-film solar modules, the area you need is:

  2.28 kWp x 15 m2 = 33.87 m2 or 2.28 kWp x 161 ft2 = 367.08 ft2

Finally, to find out how many solar panels you need, you should divide the total installed power by the rated power of a single panel you are going to buy, and round the result up to the nearest integer.

For example, if you have chosen to buy panels of 160 Wp rated power each, the number of panels required is:

2,280 Wp / 160 = 14.25, which should be rounded up to 15.

Please, have in mind that such a number is reasonably exact for budgeting purposes only.

The reason is that solar panel output power changes with temperature and solar energy deviation. Such power output deviation forms the ‘operating window’ of a solar panel.

Apart from the installation, nearly no maintenance is required for the solar panels as here are no moving parts involved and solar cells never expire. Experts from the industry state that functional lifetime of solar panels are more than thirty years. The solar panels are manufactured in such a way that they can easily withstand the various elements of nature like rain, snow or hail. Therefore, unless there is some extreme weather condition these panels work just fine without any problem at all.

What are Solar Panels Made From?Solar Panels are made using crystalline silicon and gallium arsenide. While silicon is popularly used in making microprocessors, gallium arsenide is an expensive substance used in make solar cells. In addition, solar panels are also made using alloy of amorphous silicon, where a regular roll-to-roll procedure is used. Solar cells made from this procedure are known as Amorphous Silicon Solar Cells. The solar panels made through this method are highly efficient, durable and also thin compared to those made from crystalline silicon.Solar Panels for Space ProbesWhen, it comes to making Solar Panels for space probes that depend upon solar energy, the solar cells are made using gallium arsenide through the process of molecular beam epitaxy. These solar cells have many p-n junction diodes, which are highly efficient in absorbing specific parts to the solar spectrum. Even though the efficiency of this type of solar panels is very high, the materials and processes make it highly expensive for them to be used for household use.

The latest solar panel technology is based upon quantum and molecular level. They are made through the implantation of quantum dots or carbon nanotubes into treated plastic. Contrary to solar panels made from crystalline silicon, these solar panels are not made in clean rooms, thus reducing the costs of production.

Cost of Solar Panels in IndiaAt its initial level of introduction in India, Solar Panels are quite expensive. The price of A grade Monocrystalline Silicon solar panels in the country falls somewhere within the range of Rs. 90 to Rs. 130 per watt. Then, there are other manufactures who can supply you the panels at prices ranging between Rs. 72 to Rs. 92 per watt. The warranty offered by most of the manufacturers ranges between 10 to 15 years.Manufacturers of Solar Panels in IndiaAs of 2010, Solar Semiconductor Pvt. Ltd. was the leading manufacturer of Solar Panels in India. The company, using monocrystalline and polycrystalline technology for panel making sold over 160 MWp of solar panels in 2010. The second leading manufacturer is XL Telecom & Energy Ltd. that uses polycrystalline technology to make solar panels. It had also sold approximately 160 MWp of solar panels in the same year.The next leading producers of solar panels in the country are Tata BP Solar India and Titan Energy Systems Ltd., both making 100 MWp of panels and both use Monocrystalline and Polycrystalline technology. Moser Baer Photo Voltaic using both the technologies is the fifth leading manufacturer of solar panels in India, having made 65 MWp of panels in 2010.

Installation of Solar PanelsSolar Panels are mainly installed on various types of roofs. They could be mounted as tilted up or as flushed up. If it is possible, it would be ideal to install the panel mounts whenever your home is undergoing are-roofing. When solar mounts are flashed when re-roofing, it is going to eliminate any chances of the developing any leaks in the roof. In addition, it is convenient to point out the rafters when the roof is not installed.

It is important that the mounts should be secured in place using lag bolts made from stainless steel, to be bolted right into the rafters. One of the best things to do is to keep the points of the structural attachment flashed-in. This is going to help avoid the removal and re-installing costs of the panels for decades. The easiest roofs to install Solar Panels are the composition shingle roofs. However, it can be a challenge to install the panels on tile roofs.

Even though the initial cost of purchasing and installing Solar Panels can be an expensive deal, but in the long run, the future of solar power technology is promising and it is going to grow like anything.

f energy production domestically. It thus makes it highly important for households to switch to this form of energy as soon as possible.

1. Solar electricity might not  be economically beneficial for everyone

Our comment on this disadvantage of solar power:

Although prices of photovoltaics / solar panels are steadily going down and electricity prices rise gradually in the USA on average with 5% per year (in other countries with highest percentage), the  cost effectiveness of solar systems installation depends not only on solar panels prices but also on current electricity price at your location and hardware installation cost. The cost of a PV system can be further reduced by solar rebates and other incentives.

Therefore each case is different and needs careful evaluation. Replacing even partially your utility grid with a solar system however can be beneficial for you.

2. Variability of solar radiation

Our comment on this drawback:

Unfortunately the sun does not deliver the same amount of energy over different locations and different seasons.

In winter season energy generated by a PV system could not be enough to meet daily energy needs. This imposes use of either a large battery bank or additional power source, which brings certain drawbacks and higher costs.

3. Specific orientation of solar panels

Our comment on this drawback:

To provide maximum energy yield, roofs where solar systems are installed should face South (or North, if you live in Australia or New Zealand), and a certain elevation angle is recommended for mounting the PV panels.

Otherwise the system will not perform well and the whole investment gets pointless.

4. Site must not be shaded

Our comment:

Every shade has a negative impact on solar panels and as a consequence solar system’s performance drops dramatically. Shades and solar systems cannot coexist together.

While some manufacturers claim that their panels are shade tolerant, do have in mind that if only 1/4 of the panel cell area is shaded, the generated electrical power will be virtually nil.

5. A solar panel system produces energy in daytime only

Our comment:

Solar panels only produce energy during daytime and the amount of energy provided is different during that period. What is more a solar system can generate excessive energy during given hours when you do not need it.

The solution to such a problem is using an energy storage system (battery bank).

The solar array can be mounted on a roof. Another option which is becoming increasingly popular is building-integrated mounting where a PV array can actually be a physical replacement of the roof covering (on modern office buildings). Very often a PV array can be mounted on the top of a pole rack – as is the case of solar lamps in parks.

The PV array mounting type is selected by carefully considering:

Orientation towards the sun Site shading Weather at the location Roof material and bearing capacity (in case of roof mounting) Soil type and condition (in case of ground-mounting)

Regarding solar panel mounting mind the following:

Not every mounting construction is suitable for any kind of module. Furthermore certain kinds of modules are intended for a specific mounting type.

To ensure sufficient cooling of the PV modules, which leads to higher system efficiency, enough room is to be provided beneath them.

A design visa and a build permit are usually required. All the necessary applicable construction regulations are to be

complied with.

When designing a solar system it is very important to mount the solar array properly so that it would receive as much sunlight as possible.

As a rule solar arrays are recommended to install on roofs facing True South (for North America – USA, Canada and Europe) or True North – if you live in the Southern hemisphere, e.g. Australia, New Zealand.

Installation on roofs facing North (or South – if you live in the Southern hemisphere) isnot recommended.

Solar arrays should be installed at a location which is not in shade.

Direct shadows can dramatically bring down the power yield of any PV system. Often however – and this is valid especially if you live in an urban area – it is not possible to find an unshaded place around your house.

There are two main types of solar electric systems – grid-tied and off-grid. More info about these main solar system types you can find by Clicking Here.

Here are the limitations of grid-tied systems:

Can generate electricity as long as your utility is on. In case of power outage, a grid-tied system cannot generate electricity regardless of whether the sun is shining or not.

A grid-tied system (unless it’s provided with a battery backup) can only generate electricity in daylight. A grid-tied system with battery backup however is always related with higher both initial and maintenance costs.

A grid-tied electric system must match various rules, regulations and standards for solar power installations. Such rules and regulations are specific for the region and the country where you live.

Launching a grid-tied system is always related to applying for permits and preparing lots of mandatory documents in order to meet

the necessary objectives. What is more, you are dependent on your local utility grid about electricity sell/buy prices and net-metering.

Here is a list of the limitations of off-grid systems:

Unless your building is located too far from utility grid, it is not cost-effective to replace the utility grid with a stand-alone PV system.

Due to solar radiation variability a PV system does not deliver maximum performance all the year round. In winter months it is often more cost-effective to buy a hybrid system than to spend a fortune on a battery bank, relying solely on your solar system.

The electricity produced by the PV array can be stored in batteries for limited period only.

Making your home energy efficient is a must before buying a stand-alone system.

The battery banks used in most stand-alone systems require a separate, well-ventilated room, as well as certain maintenance.

What you should mind if you decide to buy an off-grid system:

During cloudy days the energy needs are to be met by the battery bank, since PV array generates insignificant amount of power.

The greater the energy consumption to be met, the larger battery required. ‘Larger’ means expensive, bulky and challenging to maintain.

In winter energy consumption is greater than in summer. In winter however, available solar radiation is much less than in summer.

If the PV system is designed to meet all the energy needs in winter (by throwing a fortune on a battery bank), the energy surplus will remain unused throughout the rest of the year. This makes the system quite uneconomical.

The longer payback period is aggravated not only by the costly battery bank, but also due to the fact that while the battery bank provides the energy required, the PV array is not operational.

A large battery bank is not well acceptable from an ecological point of view.

Click Here to find out how to evaluate whether solar power is good for your specific case.

Concentrated solar powerSee also: Concentrated solar power

Concentrating Solar Power (CSP) systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. The concentrated heat is then used as a heat source for a conventional power plant. A wide range of concentrating technologies exists; the most developed are the parabolic trough, the concentrating linear fresnel reflector, the Stirling dish and the solar power tower. Various techniques are used to track the Sun and focus light. In all of these systems a working fluid is heated by the concentrated sunlight, and is then used for power generation or energy storage.[77]

A solar photovoltaic module is composed of individual PV cells. This crystalline-silicon module comprises 4 solar cells and has an aluminiumframe and glass on the front.

Recycling

Most parts of a solar module can be recycled including up to 97% of certain semiconductor materials or the glass as well as large amounts of ferrous and non-ferrous metals.[10]Some private companies and non-profit organizations are currently engaged in take-back and recycling operations for end-of-life modules.[11]

Recycling possibilities depend on the kind of technology used in the modules:

Silicon based modules: aluminium frames and junction boxes are dismantled manually at the beginning of the process. The module is

then crushed in a mill and the different fractions are separated - glass, plastics and metals.[12] It is possible to recover more than 80% of the incoming weight.[13] This process can be performed by flat glass recyclers since morphology and composition of a PV module is similar to those flat glasses used in the building and automotive industry. The recovered glass for example is readily accepted by the glass foam and glass insulation industry.

C H A R G E Y O U R E L E C T R I C C A R W I T H

S O L A R P A N E L S O N Y O U R G A R A G E

Sales of electric and hybrid cars are rising quickly in the UK, with over 1,000 new vehicles registered in the third quarter of 2013. People are switching to using electric cars because they are the environmentally friendly option, and less polluting than diesel or petrol cars. There are also many other incentives such as low levels of car tax, and being exempt from congestion charges. Up until recently the problem for many electric car owners has been finding somewhere to charge up their car during the working day or at night, and even though many towns and cities are introducing charging points, these are still few and far between.Electric car technology is developing constantly, and one of the new branches of research is looking into converting power generated from your solar panels into power to charge the batteries of your electric vehicle.

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C A R P O R T S A N D G A R A G E S

One of the most effective and simple ways of using solar power to charge up your electric car is to install solar panels on the roof of your garage, or to build a special car port with panels installed on the roof. This means that any electricity generated by those solar panels goes straight into powering the car rather than being drawn off to be used in other areas of the house instead. Assuming you have the space, building a car port is very quick as most of them come in modular kits which are simply slotted together. This option is ideal for someone who works through the day and then wants to charge their car overnight, but perhaps

not a good choice for people who work shifts, or who need to use their car more in the evenings than during the day. 

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One of the major advantages in using solar power, whether generated from panels on the house’s roof or on the garage, is the huge cost savings. When you plug your electric car into the National Grid to charge it up at night, the electricity costs on average £3 every time you charge it. Cost for charging it from solar energy you have generated yourself is nothing. Charging up your electric car isn’t completely free though, as you have to factor in both the cost of building your new car port or installing the solar panels on your roof, then installing the special kit needed to turn your home into a charging point, which costs around £1,500. If you happen to live near a supermarket or other charging location, or if your employer provides one at work, it probably isn’t worth the added investment required to have a charging point at home too. As with all new technologies, prices are dropping all of the time though so it is always important to work through the figures thoroughly before making any buying decision. 

H O W L O N G D O E S I T T A K E T O C H A R G E ?

Most solar charging systems are designed to work overnight, for a period of at least 6 or 8 hours, which is fine if you do not need to use your car in the evenings. This is quite slow compared with the “rapid charge” points which can power your battery up to 80% charge within 30 minutes, but the same as the standard points which take the same length of time.

Again, the decision will come down to whether you have any charging points close to home or work, how convenient they are to use, and how often you will need to charge your car. There are lots of electric car websites which allow you to enter your postcode and see what facilities are available in the local area. Rapid charging points are few and far between, but are bound to increase as the number of electric cars on the road starts to rise. If you live in a very rural area, you may have to wait some time though.

Once your car’s battery is fully charged up, the car will be able to do between 80 and 100 miles before needing charged again. New research into lithium batteries is well underway in the US, and early indications are that a new generation of batteries may soon be able to extend this range to 200 or more miles between charges.

COST

Each 1,000 watts of PV solar panel produces about 1,000 kilowatt hours of electricity per year. The typical home in Western Washington uses 900 to 1,000 kilowatt hours per month, Wade said. To be completely net zero that home would need an array that produced 10 to 12 kilowatts. The median size of a solar system for a PSE customer is 4 to 5 kilowatts, he said.

How frequently should I clean my solar panels?

A: As a rule you don’t need to regularly clean your solar panels because it’s not necessary. Yes, solar panels do get soiled by dust, bird droppings, etc. but wind and rainfall act as natural cleaners, so that generated electricity remains near its optimum. You have to clean your

panels upon a heavier drop in electricity production (10-15%) occurring in very special situations, such as a forest fire in your area

What maintenance will my solar system need?

A:As a rule solar electric system need little maintenance since they do not have any moving parts. During solar system lifespan (which is expected to last between 25 and 30 years) the following components have to be replaced:

 Inverter and/or charge controller (if any) – every 10-15 years of operation

Batteries – every 5 years of operation.Our Silver and Gold Package calculators estimate annual maintenance cost of the three main types of solar systems: grid-tied without backup, grid-tied with backup and off-grid.

The Gold Package calculator of grid-tied systems without backup offers you profits and loss estimated both with and without maintenance costs included. Thus you can easily check whether a solar installer has accidentally ‘forgotten’ to include system maintenance costs in an offer to make it more attractive.

: How can I start my own photovoltaic business?

A: We cannot provide you with any publications dealing with this topic. A smart idea however is to get in touch with the marketing department of manufacturers of solar components and systems.

We recommend you our highly informational Solar Gold Package   to get the essential technical info and knowledge necessary for your solar business, with details revealed in an easy-to-read manner. No technical background is required. What is more the information, problems, possible questions and solutions are presented from a

customer’s point of view. Knowing the customer’s point of view, his/her  internal objections, hesitations and doubts towards solar energy and the way to address them, would give you a huge advantage over your competition. 

For more information about any tax credits, grants and other incentives available in your area, check the national Database of State Incentives for Renewable Energy (DSIRE). DSIRE is a searchable online renewable energy database that includes state financial incentives, programs and regulatory policies, utility programs and incentives, local government and community incentives, programs and policies that support renewable energy production.

: What happens when it snows?

A: Immediately after solar panels get covered with thick snow they do not produce electricity. However since snow easily slides off panel surface after getting melted and your panels will be again exposed to sunlight relatively soon. Furthermore power production might even boost due to the sunlight reflection in the white snow around.

: Is solar electricity produced in bright sunny days only?

A: No. The best weather for producing solar power is surely the sunny day. This does not mean that solar electricity can be generated during sunny days only. Solar electricity is produced even in fog or rainy day although in such days energy yield is just 25-30 % of the one at best weather

Do solar panels need to be tilted at an angle?

A: Ideally yes. To achieve maximum performance of your solar system, solar panels need to be tilted at a certain angle. Moreover different tilts are recommended to optimize solar system performance in summer, in

winter and all the year round. It should be noted however that for system performance tilt angle is less critical than orientation.

In our Solar Silver Package ebook ‘Save Money On Electricity: Solar Panels And Solar Power Systems Basics Exposed’ you can find all the details you need about tilt angles of a solar panel array.

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Q: How many solar panels do I need?

A: As mentioned above, the area needed to install solar panels depends on:

Your energy needs, i.e your daily energy target Available solar energy at your location Type of solar panels used (that is, solar panels efficiency)

The number of solar panels depends on the needed area and on panel size. You can easily get the number of panels required by dividing the area by the typical panel size which is 16 square feet (or 1.5 square meters).

Our Silver and Gold Package calculators estimate the area (both in square meters and square feet) you need for installing solar panel array generating your daily energy needs for the three main types of solar systems – grid-tied without backup, grid-tied with backup and off-grid.

In summary by the Solar Gold Package you can estimate:

How much solar energy is available at your location How much electric energy you can get How much a solar energy system will cost How much you will save on utility bills

What type of solar system best suits your needs How many solar panels do you need

: How will the solar panels be mounted?

A: Roof is not the only possible place to mount solar panels. There are four types of mounting used in solar systems:

Sloped roof mounting  Flat roof mounting  Roof-integrated mounting Ground mounting  Fa?ade mounting

Each one of these mounting types has its benefits and drawbacks. It should be noted that not every mounting construction is suitable for every panel type. Furthermore certain types of solar panels are designed for a specific mounting type only.

What roof type is best suited for a solar system?

A: The roofs suitable for installing solar panels should:

Be unshaded, at least between 9 a.m. and 3 a.m. every day Face South (or North – if you live in the Southern Hemisphere, e.g.

Australia, New Zealand or South Africa), within maximum ±30 degrees of deviation

Have easy access to and be not too steep Have enough free space for panel installation Be made of composite Can local Homeowners Association (HOA) stop me from

installing a solar power system on my building? A: This is unlikely to happen. Your HOA may try, but in many

states this is not allowed – like, for example, in California. You should mind however that your HOA may ask you to modify the

system design and/or placement for aesthetic reasons. In a case like that such changes are not supposed to significantly impact solar electricity production (a decrease greater than 10%) or cost more than $2,000.

nowadays the cost of solar produced electricity is still higher than the cost of electricity supplied by local utility grid. However, you must take into account constantly rising prices of electric energy 4-5% on average per year in the USA and higher rates in other parts of the world, which in turn may reverse this situation very soon. Moreover due to fast economic growth of Asian economy (China, India, etc.), the prices of energy are expected to be higher than forecasted.

Buying a solar system however in a remote area where utility grid is lacking may be the more cost-effective option than paying a fortune on getting connected to the utility grid. Furthermore it should be noted that if a purely photovoltaic system is not the cost-effective solution in a given case, a hybrid system comprising also an alternative power generator (wind or fuel one, in addition to the solar array) might be the beneficial option.

Although prices of photovoltaics are steadily going down and electricity prices rise gradually in the USA with 5% per year on average (in other countries the rate is even higher), the cost effectiveness of solar systems installation depends not only on solar panels prices but also on current electricity price at your location and cost of hardware installation. The cost of a PV system can be further reduced by solar rebates and other financial incentives. It should be also noted that the number of increasing solar installation is one of the factors that drives solar system prices down.

:How much does a solar energy system cost, and how much will I save on utility bills?

A: There is not a simple answer to this question. A solar system cost depends on a variety of factors, such as:

Whether the system is connected to the grid or is a stand-alone one; Whether it is battery based or not Whether solar panels are installed on the roof or integrated therein The system size (depending on your electricity consumption) Solar system rebate and other incentives reducing the price The particular components used The particular solar vendor/installer.

Your savings from a solar electric system would come from:

System’s initial cost Solar system rebate(s) available System’s annual maintenance cost Costs for getting connected to local utility grid (if you are not

connected to it) Feed-it tariffs Grid electricity price Grid electricity price annual increase rate

You can use our solar packages to estimate how much a solar energy system will cost and how much you will save on utility bills.

By our Silver Package calculators you can size, evaluate and estimate the cost of your solar system. Those calculators evaluate the three main types of solar systems: grid-tied without backup, grid-tied with backup and off-grid one.

By using our Gold Package calculators you can also make a techno-economic forecast about the financial profitability of your solar system and all the possible savings related to it. Furthermore the Solar Gold Package helps you get prepared for solar vendor selection, solar installer’s visit to your home, and also be warned against some common

tricks of solar vendors/installers, thus saving you any unpleasant surprises

Charge controllers – important battery managers

Charge controller is a device preventing batteries from overcharging and overdischarging. One of the most common problems of batteries is that they cannot be discharged excessively or recharged too often. A charge controller controls the charge by managing properly the battery voltage and current.

Charge controllers are intended to protect the battery and to deliver it as longer life as possible, while keeping the photovoltaic   system efficiency. It should be noted that charge controllers only control DC loads. AC loads are to be controlled (and disconnected, if needed) by an inverter.

The key functions of charge controllers are:

Protecting the battery from overcharging by limiting the charging voltage

Protecting the battery from deep and/or unwanted discharging. The charge controller automatically disconnects the loads from the battery when battery voltage falls below a certain depth of discharge value

Preventing the reverse current through PV modules at night Providing information about battery state of charge

The main charge controller types available today are PWM (Pulse Width Modulation) and MPPT (Maximum Power Point Tracking) ones. MPPT charge controllers are more expensive but they can boost the performance of the solar array. PWM charge controllers are less expensive but they can extend battery bank’s lifecycle at the expense of solar panels performing lower than in case of MPPT controller. Similar to inverters, charge controllers have a lifespan of about 15 years.

A charge controller costs between $500 and $1,000. This is not a fortune but not choosing the proper charge controller for your system might results in series of problems. Your solar system might either underperform or not work at all. The worst however is that other system components might get damaged. Therefore selecting charge controller should not be underestimated. What kind of charge controller to choose depends on the specific case and is a tradeoff between getting more power from solar panels and extending battery life. To get an idea what controller you need for your system you need neither dig into heavy science nor be a solar guru. You just have to know some basic info such as:

-      Which type of charge controller is recommended for a given solar system type

-      What maintenance a charge controller needs and how much are its annual maintenance costs

-      When you need a couple of charge controllers rather than a single one

-      Which charge controller type is recommended for hot climates

-      What controller to select for a small solar system

-      What controller you need to connect a 48V-solar array to a 24V-battery bank