The purpose of both micro inverters and string inverters is to convert the Direct Current (DC) generated by solar panels into an Alternating Current (AC) as the latter type of current is used in our homes.

What is meant by a string inverter?

A string inverter is also known as the standard inverter or central inverter and is a standalone box that is installed close to the electricity meter and fuse box. Each residential solar installation usually has one or may be two string inverters. It functions in a series circuit and the number of individual solar panels is usually 6 to 10 and this is what is called the “string.”

How is a micro inverter different from a string inverter?

A micro inverter works in a parallel circuit. A string inverter will cap the production of electricity of each panel by the lowest producing one. But in case of micro inverters full advantage of the production of every individual panel is taken. It will transform the power generated by each panel to the grid voltage.

Micro inverters perform the same basic function like the string inverter. But these are installed beneath every panel on the roof. Every micro inverter is almost the size of an internet router. The greatest difference is that in case of installation with micro inverters the number of micro inverters needed is equal to the number of solar panels.

What are the advantages of string inverters?

The advantages of string inverters are enumerated below –

• The economy is an advantage as in case solar panel installation of single string inverter the cost is usually less than installing micro inverters.
• You need only one string inverter. In the case of solar panel installations, if anything fails it is the inverter. As such it would be less likely that you will have to go back to a job if you are an installer.

What are the disadvantages of string inverters?

In the case of string inverters, the solar panels need to be wired in series. So if the output of one solar panel is adversely affected the total series is affected equally. This can become a major issue if a part of the solar panel system remains in shade for a part of the day.

What are the advantages of microinverters?

The advantages of microinverters are –

• If your solar system faces multiple angles which means that some panels are facing east, some south, and some west, then microinverters are the best solution.Again if there are shading issues like a big chimney or trees, microinverters are ideal. This is because in such conditions, the solar panels producing various amounts of electricity at different times of the day, with micro inverters you will harvest all of the energy. But you will lose some production with string inverters. Only if all the solar panels are facing the same direction and the shading issues are minimal, string inverter can be your option. This is because the production will be the same at less cost.
• Microinverter usually has a 25-year warranty while string inverters have 5 or 10-year warranties. The technology has advanced so much that the question of reliability of micro-inverters has decreased. Also, big warranties have made them more attractive.
• The main advantage is you can yield more solar electricity. This is because there are few voltage differences between solar panels. But if the solar panels are in a string, the voltage is decreased to the voltage of the lowest voltage panel in the string.
• Optimizers are options for both string inverters and micro inverters. With an optimizer, you have a standard inverter. But you also have optimizers for every panel fighting the differences in production.
• Microinverters and the add-on optimizers enable you to track the production of every individual panel. But with string inverters, you are able to track the production of the total system only.
• Again if you wish to expand your system later, it is easy to add micro-inverters one at a time. But with string inverters, the cost will escalate for addition of another full unit.

What are the disadvantages of micro inverters?

The disadvantages of micro inverters are –

• You will have as many inverters on your roof as the number of solar panels.
• The price is huge. It is usually $1,000 or more expensive as compared to string inverters in a normal 5kW residential solar installation.

In the solar system, the most complex electronics is the inverter. And this is the most likely thing to fail in the entire setup. So setting up 20 inverters can be an issue and as such string inverters score better unless there are severe shading issues.

In the case of microinverters, each panel can be monitored but the customer is not allowed to do the monitoring. The installer is allowed to see the panel level data from your system and not the customer unless you are agreeing to buy a higher level of monitoring as an upgrade. It is really quite difficult to find out if one or two inverters of the approximately 25 have failed with only system-wide monitoring data.

However, micro inverters have their benefits. Just be ready to pay the extra money for the level of monitoring that can give you panel level analysis. Also when a string inverter fails, the entire system will stop working.

So micro inverters are only a plus if your panels face different orientations or there are shading issues. If not, the less costly string inverter scores over the microinverter.

 

 

If you are thinking of going solar, there is no harm in learning a bit about it. At least, how it is generated? For us who are not much aware of the science behind the generation of electricity from the energy of the sun by the solar panels, an obvious question is – Is the heat or the light energy of the sun used by the solar panels to generate electricity?

And since heat and light energy are almost experienced in tandem, the question becomes trickier! The following guide will in all probability answer all your queries and doubts!

How Do Solar Panels Generate Electricity?

Solar panels generate electricity with the light from the sun and not the heat. With a change in temperature, there is hardly any change in the amount of energy absorbed by the panels but the amount of electricity generated from the absorbed energy varies. The efficiency of a solar panel drops when it gets too hot or too cold. Solar panels, in fact, perform better in a bit more cold than too much heat.

The photons in natural daylight are converted by the panels for the production of electricity. Here heat has no effect. Solar panels use silicon which helps in the production of electric current from daylight.

Even if it is cloudy, it works. This is because daylight is essential and not sunlight. Obviously, with direct sunlight, the panels would definitely perform better. But modern panels have concentrators that maximize the light the cells receive with the aid of mirrors and lenses. Thus solar panels are 40% effective in cloudy weather. Here the size of panels is significant too – larger the better. The best part is that you are “going green” with solar.

Do Solar Panels Use Light or Heat Energy?

A solar panel uses both light and heat energy from the sun. But the most important part harvested by a standard solar panel is the light. The solar panels use photovoltaic effects from the harvested light energy of the sun and convert the light energy directly to electricity.

Thus it is actually the light that generates electricity and excess heat may actually deter the process of electricity production. Higher temperatures will cause a reduction in the efficiency of electricity production. Thus, though solar panels absorb both heat and light, the light is what is actually needed. But this is the norm for PV solar panels which are the standard ones. But then there are thermal solar panels that have a different style of functioning.

Are There Solar Panels That Utilize The Heat Of The Sun To Generate Electricity?

Some solar panels use the heat of the sun to generate electricity and such panels are called thermal panels. The sunlight heats up the panels which can be used to generate steam and electricity or household hot water.

But such panels are less installed in homes because their integration with water systems is quite complex and managing these are not easy. Also, they lead to a bigger discrepancy between the cold and hot days and are thus less reliable than the standard PV solar panels which depend entirely on light.

Why Is Using The Light Of The Sun To Generate Electricity More Efficient?

When you use the light energy of the sun to generate electricity it is more effective as the ultraviolet and infrared light that we cannot see is also utilized.

But the light needs optimization. Like in the case of home installations, the panels should be properly oriented to get the maximum sunlight. And when it is freezing cold weather or snowing, solar panels will use the heat to produce enough electricity only if there is optimal sunlight.

But you cannot optimize the heat coming from the sun in any effective way. It entirely depends on temperature – the degree of hotness – which is not very reliable. One other problem with heat-led solar panels is that with rising temperature the electrical resistance of the circuits increase and so more work is required to produce an equal amount of electricity.

Why Efficiency Decreases In Too Hot Conditions As Compared To Cold Ones?

The atoms vibrate faster inside a hot solar cell than in a cool solar cell. Sunlight excites the electrons within the atoms to a higher level thereby generating electricity. Excess heat causes the atoms to vibrate faster as a result of which the electrons within the atom find it difficult to get out. If this is the situation, the energy never gets converted to electric current.

If you look at it in another way, solar cells are able to produce electricity when the electrons move from a lower energy state to a higher energy state. But when a solar panel becomes hot, the difference between these two states becomes very less and so no energy is formed.

But when the panel is cooler, the electrons in the solar cell get excited due to the sunlight and easily move to a higher level of energy. This happens because the atoms are not vibrating. And so, though the electrons are moving slowly, those that move through carry more energy than those in a heated state.

How Does The Efficiency Of A Solar Panel Vary With Temperature?

The efficiency of a solar panel falls by almost 0.05% for every degree Celsius rise in temperature. But with the fall of every degree Celsius of temperature, the efficiency increases by 0.05%. Here “temperature” means the temperature of the panels and not the temperature outside. But air temperature is definitely going to affect the panel temperature.

Again efficiency depends on the hardware and the design of the solar panels. Usually the term “temperature coefficient” is used by the solar panel manufacturers for the measurement of how well a panel handles cold or heat. This is the range of temperature within which the panel can give its best produce.

Why Cooler Is Better ForSolar Panels?

The best weather condition for a solar panel is sunny, cold, and windy. In such situations, the panels get lots of energy from the sun, remain cool and the wind moves away from the normal levels of heat created within the panel itself. But definitely bitter cold arctic temperatures will obviously slow down solar energy production.

Thus cooler temperatures are actually better for the energy production of solar panels. While the warmer regions make up for the excess heat with more sunshine. Though cooler regions being away from the equator have less advantageous angles of receiving sunlight, they make it up when the sun is shining.

 

Solar energy is an investment that pays for itself as the upfront cost is paid back by the reduction in the energy bills and the customer may see a return of a minimum of 2-3 times the initial investment he made during the lifespan of the solar system. But that only happens if you stay in the same house for the entire time of the warranty. But, practically, this hardly happens. You move and need to sell your house. In such cases, the question crops up that whether the initial investment will be recovered?

If you own the house, the problem is solved as the grid-tied solar system will increase the property value of your home. And even if you do not stay in your home long enough to break even the upfront costs, the extra you get from home buyers who are eager to move into your solar-ready home will more than cover up your investment.

What is the average premium that solar homes get at the time of selling?

 

According to a study conducted across 6 states on the sale price of 22,822 homes, the sale value of 3951 PV homes was compared to that of 18871 non-PV homes. The study says that the home value is increased by $14,329, or 3.74% more for PV homes on an average as compared to the non-PV ones.

The average cost of materials is $10,000 – $18,000 and the home owners are able to get the same back when they sell their homes. This is what they get in addition to the savings they made on the tax incentives and reduced energy bills which probably has paid 2-3 times for the system over the life warranty.

But there are some states which do not count PV systems towards the home value when calculating property taxes. This depends on local regulations and is not the same everywhere in the US.

Now let us delve into this in details

Real estate is a very complicated market and there are innumerable factors that influence the value of a property. Let us take into consideration the following issues :

Reducing Returns on Larger PV Systems

Homes which are solar-equipped sell at a significant premium irrespective of the output wattage of the system. But that does not mean that the sale price of homes with stronger PV systems will increase in proportion with the installation expense of the system.

Homebuyers are ready to shell out some more for owning a ‘solar home,’ irrespective of the efficacy of the system or the capacity to entirely cover their expected energy usage. They will pay a bit more for the larger systems but not proportionally to the worth of the system.

So those who intend to sell, it would be sensible to install a modest grid tie system which depends on stored solar energy most of the year, but pulls from the grid at times of heavier needs. This offers a flexibility of marketing your solar home in the listing while keeping the cost of installation down and making a profit when the sale occurs.

Again….

Selling Solar Homes May be a Longer Process

According to study, solar-equipped homes may take a longer time to sell than the non-PV homes and this extra time is roughly 8 days. This data changes from state to state depending on a few factors like –

Small Sample Size in certain States

The data from CA is way more robust than that from other states which is why its numbers come closest to the national average.

• Variable Incentive depending on StateSome states offer stronger incentives if you buy a solar home. Again there are others which offer no incentive. If there is no incentive, then the solar homes will stay longer in the buying list.
• Local Perception of SolarSolar power has received wider acceptance in areas like FL and CA as there is a lot of sunshine there and huge benefits are given for going solar. But this topic has not received so much education and adoption from other states.

  If the locality has poor benefits for solar adoption and lower electricity costs, there will be less awareness among the people regarding solar as an alternative energy resource. Consequently, buyers will hesitate to buy a solar-powered home as they are not convinced about its reliability. Also they may not realize the long-term benefits of selling a solar-powered home.

  In states where solar education is low, people may not understand the difference between off-grid and grid-tied systems. They usually think that such systems are all off-grid which depend on panels to produce 100% of the energy and run totally on a battery storage system. They think that they will remain without power if the solar array goes out and they do not know how to fix it.

  Actually, most systems are grid-tied and generate their own energy but remain hooked to the public utility grid. The panels are not required to produce 100% of the electricity of your home. The grid can chip in at times of heavy usage. And at times of power outage, the public utility workers fix the problems and get things running smooth as quick as possible.

  In areas where solar energy is not popular, the buyers have to be educated a little so that they get convinced to buy the solar-powered home.

Is The System New Or Old?

Newer PV systems are made from more efficient materials, are less likely to need replacement of parts and have more years of warranty left. With the aging of the PV systems, their value falls and these become less valuable when they are put in the home market for sale. So newer installations are always a bigger boon for property values as is to be expected.

Which is better – Leased or Owned systems?

The premium is only applicable to those homes which have host-owned PV systems. If you had agreed to a solar lease or PPA (Power Purchasing Agreement) with the developer who had installed the system you are not likely to see the higher sale price coming to you as profits. In such situations, the buyers will ask the previous owners to pay off their lease or PPA agreement which will offset the extra value built into the final sale price of the home.

So you get the extra cash on selling the property only if you have bought the PV system outright.

Anyways, solar is a good investment. If you stay in your home for the warranty duration, the grid tie system is going to pay 2-3 times or may be even more in energy savings and tax breaks.

But even if you think about moving before the warranty period is completed, the value of the system converts into a bigger sale price when you put up your home for sale in the market. And this value will be enough to cover the hardware costs. Thus the homeowners break even right at the beginning of their solar investment.

 

Batteries have their variety, both in terms of size and shape. Of these, the lead-acid battery is quite frequently used in the solar industry. The lead-acid variety also has its types. It is broadly classified into two categories – the flooded lead-acid battery and the sealed lead-acid battery.

Again the second type, that is, the sealed lead-acid battery has two groups – the Gel batteries and the AGM (absorbent glass mat) batteries. Read on to find out more about these batteries, compare between the AGM battery and the Lead-Acid battery and learn about the pros and cons of each.

Flooded Lead-Acid Batteries

This kind has been the standard battery in the solar industry for a long time. These are most durable, long-lasting and cost-effective amongst the lead-acid batteries.

The flooded lead-acid batteries contain an electrolyte that can move around freely in the battery encasement. On charging the lead plates react with the battery acid to store electricity.

These batteries require to be mounted erect so that there is no leakage of electrolyte. They are the most economic and if well-maintained will reach the potential lifespan. But you have to check the levels monthly and top off with distilled water so that the lifespan is maximized.

These batteries release toxic hydrogen gas at the time of charging and this needs to be enclosed and vented to the outside so that the gas does not get trapped resulting in a hazardous atmosphere.

Pros of Lead-acid Battery

• The lead-acid batteries are the most cost-effective
• These are long-lasting
• Best choice for backup power applications, grid and utility energy storage

Cons of Lead-acid Battery

• These batteries have to be mounted erect to prevent leakage
• These get damaged in regular movement
• These require regular maintenance
• With these batteries, you need to check the levels periodically and top off with distilled water
• These batteries release toxic hydrogen gas during charging which needs to be vented out so that a hazardous atmosphere is not created
• Extreme climates have a deterrent effect on these batteries as the electrolyte solution inside may freeze or evaporate

Sealed Lead-Acid Batteries

The sealed lead-acid batteries are quite similar to the flooded version except that there is no access to the inside compartment. As such the electrolyte is sealed inside and you do not have to add distilled water. The amount of electrolyte is just enough so that the battery can live a calculated number of cycles. These batteries are also called VRLA (valve-regulated lead-acid) batteries as these have a small valve that allows the gases that occur during charging to escape. The two types of sealed lead-acid batteries are here under –

1) Absorbent Glass Mat (AGM) Batteries

Absorbent Glass Mat batteries are a variety of VRLA battery which is most popular as these can work in a wide range of conditions. Here the electrolyte is suspended in a thin fiberglass mat which is situated between the lead plates. This helps in the battery to be resistant to vibration and thus is the ideal choice for RV and other mobile applications.

These batteries can be mounted in any orientation and can be seen mounted in their sides to facilitate wiring and placement.

But AGM batteries are comparatively expensive than the flooded lead-acid ones and are not so long-lasting also. But they require very little maintenance. Also, you need not deal with that much gas released during the charging phase.

These batteries are ideal for mobile applications, remote locations where regular maintenance is quite impossible, places where leaked acid can cause problems and where the batteries will have to withstand very cold temperatures.

Pros of AGM Battery

• The AGM batteries can be mounted in any orientation as there is no fear of leakage
• These need very little maintenance
• These are resistant to vibration
• Too much gas is not released during the charging phase
• These batteries can handle higher charge/discharge rates
• These batteries are most commonly found in off-grid power systems, renewable energy systems and are useful for electric vehicle service and uninterrupted power supply systems (UPS) and also for robotics, solar street lights, some ATVs and motorcycles

Cons of AGM Battery

• These batteries are more expensive
• These are not very long-lasting
• These batteries should not be over-charged or under-charged as that can affect their performance and life

2) Gel Batteries

This second kind of VRLA battery is quite similar to an AGM but uses a thick paste that allows the magic to occur than the fiberglass mat. The main difference between the two is the charge rates. The AGM batteries can handle higher charge and discharge compared to Gel batteries. Again the Gel batteries are more costly than AGM and last longer in hotter temperatures. So, if the temperature of the place where the battery is to be used is a concern, you may go for the Gel batteries.

These batteries are the most expensive and are thus not quite perfect for quite some specific solar applications. Gel batteries are quite often mistaken for AGM batteries and this can affect their lifespan. But they are again the most sensitive VRLA batteries and it is advisable to use the correct charging parameters when you are using a Gel battery. These batteries can withstand high temperatures and perform best with slow, deep discharge.

 

 

Solar batteries are the most expensive component of an off-grid solar system. And it is really important to practice a regular maintenance schedule so that the batteries run effectively for years. If proper maintenance and setup routine is not followed, the lifespan of the batteries will be shortened. Here we are trying to guide you as to how to program and maintain your battery, whatever its type, so that they run efficiently and smoothly over a long period.

1. First Step – Initial Programming

You have to program your battery chargers to the proper charging settings for the battery bank the very first time you bring your system online. The settings will control other parameters like current and charging voltage. Now you need to set voltage set points which are the charging voltages applied to the battery at each stage of the charging cycle. The three charging phases of the batteries are absorbed, bulk and float. Let us learn a bit more about these –

Bulk – High current to refill charge and increase the voltage as quickly as possible (below 80%)

Absorb – Here the charge rate will slow down as the batteries approach the full state of charge (80 – 100%)

Float – Batteries will receive a trickle charge at 100% to stay completely charged

Each of these stages will require the charger to be set at a particular voltage depending on the needs of your battery. You need to program the voltage set points accurately to ensure the longevity of your batteries. If wrong charge parameters are set, the batteries will charge improperly thus decreasing their lifespan.

Along with this, you need to set certain other values in the initial programming phase, which are –

AC input amps – The input current from the generator or grid has to be maximized so that the combined current from the loads and battery charger does not become more than the generator rating. It also depends on the grid input breaker or generator size.

Temperature Compensation – The battery charger has to be adjusted to operate in different temperature ranges. Most of the chargers come with a battery temperature sensor.

Absorbs Time – It is the amount of time the charger spends in the absorb phase.

Max Charge Current or Charge Rate Limit – The maximum charging current is expressed either as a percentage of the charger output or total maximum charging amps. The charger output is limited by using this setting so that the batteries are not overcharged with the excess current.

The settings will vary with every battery and charger and you should check the installation manuals and spec sheets of the chargers and batteries to find the exact value for each of the above-mentioned settings. You need to program the equipment based on the recommendations in the manual for the long life of the battery bank.

2. Maintenance of Flooded Lead-Acid Battery

Flooded lead-acid batteries need daily maintenance for proper functioning. A check after every 2-4 weeks is necessary for proper tuning of the battery bank.

These batteries lose water during the charge cycle and need regular refilling with distilled water so that they stay healthy and work properly. But you should use distilled water only; otherwise, contaminants and small particles will get introduced into the system weakening the chemistry of the battery.

The water level is to be checked after every 15-30 days and refilled if required. The watering schedule is entirely dependent on the charge settings, local climate, and specific application. It would be wise to maintain a log entry regarding the frequency of refilling batteries.

• Check the water level when the batteries are completely charged
• Check the water level by opening the vent well
• Add water but it has to remain just below the maximum water level line. Overfilling past this line is a strict no-no. You will get to know the location of this maximum water level line from the battery installation manual.

Certain safety procedures need to be followed while working with batteries like wearing gloves and eye protection, securing long hair or loose clothing and removing any jewelry.

3. Checking the Battery State of Charge (SoC)

You need to keep an eye on how charged your batteries are and for that, you need a refractometer. The refractometer keeps a measure of the specific gravity of the batteries. If the batteries are not holding charge even after a complete charge cycle and equalization, they are probably damaged, defective or need retirement and are starting to lose some capacity.

Battery monitors are used by some inverters for measuring the state of charge. The monitors depend on a shunt to measure the total current coming out and in of the battery bank. The monitors are good tools for regular monitoring but need proper setup. If they are programmed or installed incorrectly, they may come up with false readings. Whether you have a battery monitor or not, checking with a refractometer regularly is recommended. It gives you the charge condition and accuracy of your batteries.

Equalization Charges

Batteries need to be equalized frequently so that each cell is equally charged. A controlled overcharge is to be applied every 30-90 days or whenever there is an imbalance in the individual batteries.

Process of Equalization

• The water level has to be checked before starting the process
• The loads are to be turned off
• The charger has to be set at the Equalize voltage as specified in the battery manual
• The Equalization charge has to be started during which bubbling and gassing are normal.
• Finally, stop charging and take readings of specific gravity every hour and when the specific gravity stops rising, the process is complete

What are the other Maintenance Routines of Flooded Lead-Acid Battery?

• The cables and terminal connections need cleaning to stop corrosion. A paste is to be prepared by mixing distilled water and baking soda and then applied with a wire brush. Then the cleaning residue is to be rinsed and dried with a paper or cloth towel.
• The battery cable connections need to be tightened
• The top of the batteries should be free from debris and dust to prevent the creation of electrical leakage or a current pathway across the top of the battery.

4. Maintenance of Sealed Lead-Acid Battery

Sealed lead-acid batteries require minimal maintenance as these do not need to be filled with water or equalized. Only the state of charge of the battery requires occasional check-up.
Checking the Battery State of Charge (SoC)

You need a multimeter to see how charged the sealed lead-acid batteries are based on the voltage. A multimeter comes with negative and positive probes that allow the meter to get a DC voltage reading from the battery. Guidance in this regard can be got from the battery manual.

For the most accurate readings, the batteries must be tested in a resting state. The batteries should be rested for a minimum of 2 hours before the voltage reading is taken. You will get inaccurate readings if you use the multimeter when the batteries are being charged or discharged.

If the batteries do not approach 100% SoC even after a complete charge cycle, they are damaged, defective or have reached the end of their lifespan. The sealed batteries do not need equalization charges.

5. Maintenance of Lithium-Ion Battery

Lithium batteries need little to no maintenance. They hardly need any check-up after set up except the occasional state-of-charge reading to ensure that the batteries are holding charge.
The state of charge (SoC) of a lithium battery can be measured by a tool that communicates the built-in Battery Management System (BMS) to give an accurate SoC reading. The monitoring tool has to be hooked up to the battery and the SoC value can be read on the display screen.

What are the other Maintenance Routines of Sealed Lead-Acid Battery and Lithium-Ion Battery?

• The top of the batteries should be kept clean to stop them from becoming grimy and dusty.
• The battery cable connections should be tightened

6. Prevent Sulfation

Lead-acid batteries face the risk of sulfation if they remain unchanged for a long time. Sulfation happens when lead sulfate crystallizes and the battery is no longer capable of accepting a charge. Once this happens, the battery is as good as dead. They are no longer able to conduct a current. To avoid sulfation, the battery has to be recharged fully after a discharge cycle. Also, periodic charge cycles are necessary to keep the battery healthy. The ultimate solution for sulfation is prevention.

7. Cooling Off Period to the Battery

The battery needs a ‘rest’ period after usage and recharging when it remains inactive until it cools off. If used immediately after recharging, it runs the risk of getting burnt out making it incapable of working to the best of its abilities. This is because like a lot of heat is generated during a recharge cycle, running it right after it may cause grid corrosion resulting in total battery failure.

8. Avoid Stratification

Stratification of the electrolyte in the battery occurs due to partial charging and discharging occurring again and again. This significantly decreases the performance and capacity of the battery. The balance of chemicals is thrown haywire. The acid seeps to the bottom of the battery and its absence at the top limits plate activation. This can be rectified by the slow process of diffusion, the mechanical stirring of the electrolyte and the regular running of the battery.

 

 

If you have decided to go solar but do not know which type of solar panel will suit your requirements the best – monocrystalline or polycrystalline, the following study will probably be of great assistance. This will help you to know about the types, their key differences, their merits and demerits, a comparative study and finally the factors based on which you can make your choice!

What Is The Main Factor That Differentiates Monocrystalline Solar Panels From Polycrystalline Ones?

Polycrystalline and monocrystalline solar panels work the same way in the solar PV system. They trap the energy from the sun and transform it into electricity. Both are made from the durable, abundant element, Silicon. The main difference between the two is the kind of silicon solar cell used for each. For the monocrystalline solar panels, the solar cells are made from a single crystal of silicon. But for the polycrystalline variety, the solar panels have cells made from many silicon fragments melted together.

What to know about monocrystalline solar panels?

Monocrystalline solar panels are premium solar products having higher efficiencies and sleeker aesthetics. To make solar cells for monocrystalline panels, silicon is made into bars and cut into wafers. The silicon used is single-crystal silicon and as the cell is made of a single crystal, the electrons that cause the flow of electricity have more space to move. Thus, efficiency-wise, monocrystalline panels are far better.

What to know about polycrystalline solar panels?

Polycrystalline solar panels are less efficient than the monocrystalline varieties and naturally are lower priced too. These solar panels have a blue hue while the monocrystalline ones have a black tint.

Polycrystalline solar panels are also made of silicon. But in place of using a single crystal of silicon, many fragments of silicon are melted together to form wafers for the panel. These panels are also known as “multi-crystalline” or many-crystal silicon. Due to the presence of many crystals in each cell, the electrons have less freedom to move and consequently, the efficiency of polycrystalline panels is less.

Polycrystalline solar cells usually have a lower temperature coefficient than the monocrystalline ones. This temperature tolerance will help it to generate more electricity over the year.

What are the advantages and disadvantages of monocrystalline solar panels?

The advantages –

• Smaller installation area required
• Good performance under low irradiation conditions
• High efficiency
• Long life-span (25-year warranty)

The disadvantages –

• When solar panel gets covered by dirt, snow or shade, circuit breakdown occurs
• Wastage of silicon at the time of manufacturing
• Most expensive
• Performance falls while increasing the operating temperature, but not significant enough and less than polycrystalline

What are the advantages and disadvantages of polycrystalline solar panels?

The advantages :

• No silicon waste
• Cheaper and simpler manufacturing process

The disadvantages :

• Needs more installation area than the monocrystalline variety
• Lower efficiency due to low silicon purity
• Lower architecture integration
• Lower performance while increasing the operating temperature, not significant enough

How about a comparative study between the monocrystalline and polycrystalline solar panels?

Comparison factors	Monocrystalline	Polycrystalline
Efficiency	More; even better in low light condition	Less, more so in low light condition
Longevity	25+ years	25+ years
Cost	More expensive	Less expensive
Aesthetics	Uniform Black hue	Bluish hue – uneven texture and hue
Manufacture	Silicon is formed into bars and cut into wafers	Fragments of Silicon are melted to form wafers
Wastage	More wastage in production	Less wastage during manufacturing
Space	Less	More
Temperature Tolerance	Less	More

Which to choose – Monocrystalline or Polycrystalline?

The main reason for going solar is precisely “saving money.” You will reduce your utility bill irrespective of the kind of panel you choose. What are the other factors that you need to consider before making your final choice? Let us find out ……

Space Limitations – If the amount of space available on your roof is limited, you should go for the more efficient solar panels. In such cases, monocrystalline solar panels are better suited as these would maximize electricity production. But if you have a lot of space on your roof or are installing ground-mounted solar, you can opt for the lower-efficient polycrystalline variety as that would be more economic.

Personal Choice – If the color of your solar panels is a point of concern for you, the typical monocrystalline solar panel will have a dark black color while the polycrystalline one will have a bluer shade. It is for you to choose.
Again if the manufacturer is of utmost importance, find out the name of the company where the panels you are to install have been manufactured.

Solar Financing – The way you finance your system can be another controlling factor. If you go for a power purchase agreement (PPA), you pay for every kilowatt-hour of electricity produced by your system. This shows that your monthly payments will determine the savings you make. On the other hand, if you are buying your system, if you pay for the more efficient monocrystalline panels it can result in higher returns on your investment.

Locality – If you are living in low-light areas and a less hot region, it is better to go for the monocrystalline variety as these are more effective in such conditions.

The option you go for is entirely based on your personal needs, space constraints, preference, financing option and more. But before doing so go through a proper comparative study of the two types and find out which suits your needs the best so that you make an informed choice because you do not change solar panels every other day!

 

Are you thinking of installing a solar energy system for your business or residence but are undecided as to whether to go off grid or grid tied? If this is the case read on to learn what these terms mean, what components are needed for each, the pros and cons of each system and then make an informed choice to suit your interests best.

What is Grid Tied Solar System?

Grid-tied means your solar system is tied to the GRID of the local utility. Most residential homes will use this as it will cover if your solar system under-produces or over-produces depending on your varying energy requirements. In such cases, your utility system will be behaving like your battery space. So when your solar panels or system is producing more energy than your requirement, the excess energy is sent to the grid’s power company. This allows the building of credit which you can cash on later at the end of the year and this process is known as net metering. While if your panels are under-producing, you can get the rest of your requirements from the local grid.

Living with a grid-tied system is quite alike as living with utility electricity, only that some or all of the energy comes from the sun. Grid-tied solar systems need a power meter and Grid-Tie Inverter (GTI) or Micro-Inverters for functioning.

What is the Off-Grid Solar System?

In the off-grid system, it requires that the solar panels can produce enough electric power to cover the entire need of your household. This system means your solar panel or system is in no way connected to the grid’s power system or utility company. It allows you to store and save the produced solar power in batteries. This power can be used later when the power grid goes down.

This shows that this system is entirely self-sustaining. The off-grid solar system needs battery bank, off-grid inverter, solar charge controller, DC Disconnect (additional) and Backup Generator (optional).

What are the benefits of Grid Tied Solar System?

Grid tied solar, i.e. on-grid solar is beneficial as you need not buy an expensive battery back-up system to store the excess energy. It is more economical and very easy to install. It will pay for itself and you will be able to offset bills in 3 – 8 years. It will add money to your pocket in the long run. This is your way of reducing your electric bill. Also, you will be reducing the carbon footprint. It benefits the community as a whole.

It has fewer upfront costs. Also, it is more flexible as you don’t need to install all the solar panels needed for your total energy consumption at one go. You can add more panels, if needed, with the availability of financial resources later on.

What are the Disadvantages of grid-tied solar?

The biggest demerit of this system is, it does not provide power during a grid outage. Some think that when a power outage takes place, the panels will behave as backup generators. But this is not true. This is because they are connected to the greater power grid. Also, it is very expensive to install power lines to connect your solar system to the grid if you are living in rural areas.

What are the Benefits of Off grid solar?

With the off-grid system, you can store and save solar energy in batteries to be used later when the grid goes down. Thus this is entirely self-sustaining. Also, such a system can provide power for critical loads when the power grid is down. This means that your refrigerator, pump, and a few lights will get power while the TV and air conditioners and other non-essential loads can be put on hold.

You will receive no bill from the power company and will be independent of it. This is particularly beneficial in remote areas, where the installation of traditional power poles is pretty expensive. With off-grid in such areas, your worries are saved. The off-Grid system gives you a measure of the amount of energy you are expending in a day and is bound to make you more energy conscious. Such systems are especially useful for use in RVs, remote agricultural pumps, traffic signs or boats.

What are the Disadvantages of off-grid solar?

The off-grid system needs you to buy a back-up battery. This is not only expensive but also bulky and not at all environment friendly. As a consequence, the entire purpose of going solar is defeated. Also, the off-grid system is not able to cater to the energy demand of all your loads due to the volume and cost of batteries. Again these systems need lots of specialized equipment for functioning. A central/string inverter and a charge controller are required in addition to the batteries. Also, the installation of this system is complicated.

Maintenance and periodic replacement of expensive high amp batteries is another demerit. It is more complex and less flexible. Further here, you cannot depend on the power company for backup. So, before choosing this system, you should be sure that your property can sustain without power by itself at certain intervals.

Which to choose – Grid-tied or off-grid solar?

Off-grid systems are not ideal for the average homeowners as this particular system is not at all economic. Also, maintenance and installation are not easy. An off-grid system will need 3 to 4 times the cost for a similar on-grid system. It would be wise to install an on-grid solar system and go for a backup DG if necessary. Also, off-grid is difficult to install.

But, for remote areas, the off-grid solar system is a better alternative as in these areas the grid is unreliable or unavailable.

 

You are probably already in possession of a solar charger and are in the habit of charging your car battery therefrom. But at times it becomes challenging to keep your car battery charged with a solar charger or from a wall outlet if you are far removed from civilization. It is at such times that solar car battery chargers can make your life smooth irrespective of where you are on the planet.

So if you have a classic car, summer convertible, RV and such vehicles purchasing a solar car battery charger would be a wise investment. It is an absolute necessity for people riding an RV.
A solar car battery charger protects against battery discharge and thus increases battery life. This is bound to make your purchase economical.

Tips on Solar Car Battery Chargers

• The solar chargers will also work in bad weather and shade but the charging performance will be less effective and slower.
• Solar car battery chargers are most effective in direct sunlight
• The overall bulk and weight of larger solar panels trade for faster, better performance
• Compact and easy to carry
• Durable and powerful
• Inexpensive and easy to use
• Keeps your car battery topped up always

Are solar car battery chargers useful for charging other devices or batteries?

The design and capabilities of the battery charger will determine whether it will be capable of charging other devices or batteries. Some have USB ports or other connectors for charging small devices.

Do solar car battery chargers work better than normal chargers?

Solar car battery chargers are usually slower than normal chargers due to the limitations of the solar panel.

What do you understand by the term “Trickle Charger?”

A Trickle Charger charges a battery over time and is available in both solar and regular power varieties. It maintains and increases the power level of the battery but causes no damage to the battery.

With such benefits why not find about the best solar car battery charger available in the market?

ECO-WORTHY 12 Volts 10 Watts Portable Power Solar Battery Charger for Car Boat Automotive and RV

 

This 10W 12V Trickle solar car battery charger from the house of ECO-WORTHY is the ideal solution for charging automobiles, tractors, motorcycles, snowmobiles and more. It is ideal for vehicles for travel, outdoor work or camping training. It is usually bought along with accessory 2-Pin Quick Disconnect Plug Asin B07K7DJFDY and SAE Quick Disconnect Extension Cable Asin B07KWVXVZX. It is an energy saver and protects the environment. It is easy to install, lightweight and totally maintenance-free. It is rust-proof, shockproof and dustproof.

The solar car battery trickle charger package includes one pc alligator clip adapter with 22.8” cord, one pc 12V 10W solar trickle charger with 57” cord, 4 pcs PVC suckers and 1 pc cigarette lighter adapter with 22.8” cord.

There is a constant but small battery drain. The automotive batteries discharge naturally when not in use. Modern vehicles have upwards of 30 body control modules (computers), immobilizers, alarm systems, and lock monitoring. All of these units consume electricity from the battery and so the battery can get discharged in one or two weeks even if the vehicle has not been used much. If the batteries are not kept charged their lives are shortened. So a 12V battery if not properly maintained above 12.4V will suffer sulphation and this will lead to battery failure. So the auto battery becomes dead if vehicles remain stationary for long periods.

The specifications of the product –

• Voc – 22.41V
•  Vop – 17.9V
• Working current (Iop) – 0.56A
• Temperature range: -40oC – +80oC
• Weight – 1.46 pounds
• Rated Power – 10W
• Short circuit current (Isc) – 0.61A
• Output Tolerance: ±3%

 

Cigarette Lighter

The cigarette lighter has to be plugged into a socket to maintain or charge the battery of the vehicle. So it is simply plug and play. In some vehicles, it is found that the cigarette lighter does not function when the ignition is turned off. In such cases, you have to connect the battery directly with the help of alligator battery clamps and cables.

Plug & Play SAE connector

The solar panel SAE connector is simply plug and play where you do not need to recognize the negative or positive and is thus very easy to use. But be careful to not charge your battery full as its main function is to maintain the battery.

Built-in blocking diode

The built-in blocking diode is useful for preventing reverse discharge.

Alligator Clip Adapter

The red and black battery clamps can be used to trickle charge and maintain a 12V battery. Be sure to connect these correctly.

This particular model of solar car battery charger has been highly appreciated by the customers and at the time of writing this article, it was priced around $30.00. Find out what the customers have to say about it or the exact customer rating?

 

Solar panels are a wise investment. Once installed your electric bills get reduced and you pay less every month and this effect takes place from day one. Soon you will see that the amount you invested in installing the solar panels has been recovered. But does the same rule apply to solar heaters? Can you justify the expenditure you incur for a solar heater? If these are your queries, read on to find the answers.

The answer lies in calculating and then comparing the entire lifetime costs of solar water heating as to the total lifetime savings on the costs of home energy. Let us find out….

What is the cost of installation and maintenance of solar heaters?

The cost of solar heaters varies depending on the make, size, and model of the particular unit. It can be as low as $1,000. The initial cost of installation can be brought down by almost 50 percent with the various available state, local and federal incentives. The solar water heaters are extremely durable and long-lasting having no moving parts. Usually, solar water heating systems are built in such a way that they last almost 25 years if not more and require minimal maintenance.

What are the factors which control the amount you can save?

The factors which control the amount you can save are –

• The performance of the system
• Availability of incentives and financing
• Cost of fuel you use for your backup energy source, if you have one
• The amount of hot water you use
• Your geographic location
• Cost of conventional fuels

How do you determine the energy efficiency of a solar water heater?

You can calculate the energy efficiency of your solar heater using the solar energy factor (SEF) and a solar fraction (SF). The solar energy factor is calculated by the energy delivered by the system divided by the gas or electrical energy put into the system. The higher it is, the more it is energy efficient. The solar fraction is part of the total conventional hot water heating load. The more the solar fraction, the greater is the solar contribution to water heating which decreases the energy needed by the backup water heater.

Solar energy factors range from 1 to 11 and systems having 2 to 3 SEF are common. Solar fractions range from 0 to 1 and typical SF is 0.5 – 0.75.

How to calculate the annual operating cost?

It would be wise to calculate the annual operating costs for various systems before purchasing a solar water heating system as then only you will get to know the payback period and energy savings and make an informed choice. But to start with, you should know the system size needed for your home. You need to know the solar energy factor (SEF) of the system and the type (electric or gas) and the costs of the auxiliary tank fuel. Then the calculation goes thus –

A) With a gas auxiliary system

In Btu
365 x 41, 045 ÷ SEF x Fuel cost (Btu) = estimated annual cost of operation

In therm
365 x 0.4105 ÷ SEF x Fuel cost (therm) = estimated annual cost of operation

1 therm = 100, 000 Btu

B) With an electric auxiliary system

365 x 12.03 kWh/day ÷ SEF x Electricity Cost (kWh) = estimated annual operating cost

Finally, you can compare the solar water heating system with the conventional ones knowing the annual operating costs and the purchase value. This way you will also get to know the cost savings and the payback for the solar water heating system and compare effectively.

How much can you save on utility bills with your solar water heater?

Here again, the perfect figure is dependent on the manufacturer, size, model and the typical water usage of your home. A family of five members will save more as compared to a family of two. The monthly utility bills are on average reduced by 50 percent to 80 percent with the use of solar water heaters according to the U.S. Department of Energy. If that is the amount you save, you will recover the amount you expended for solar water heaters quite quickly – within 5 to 10 years.

It is worthwhile to mention that your current payback periods are linked to the utility rates of today. With the rise in energy prices, the payback period of the solar water heater will get shorter as the installation will protect you from the escalating utility prices.

Are there any demerits with the installation of solar water heaters?

Let us find out if there are any demerits with solar water heaters.

The installation of a solar water heater is expensive. So the initial investment is high. But the same can be recovered from the savings you get in your monthly energy utility bills.

The location where you mount your heater should have enough exposure to the sun. Those living in warm sunny areas are to benefit more as compared to people living in cloudy, cold environments like the Pacific Northwest. It might not be economical for some places.

If the water quality of your area is acidic or hard, the water circulation system may get corroded.
A solar water heating system may be considered to be too heavy when mounted on your roof if you are living in a seismic zone and there are certain building regulations.

With continuous bad weather, you will need to have a backup energy source.

Solar water heating systems need more maintenance.

What are the added benefits of solar water heaters?

The primary benefit is the lowering of the monthly utility bills. You will not require electricity for heating your water. Only if you require pumps will you need some amount of electric power? There are a few more benefits which are quite significant too.

The first is the lessening of carbon footprint. While gas or electricity causes pollution, solar energy does not. They get their entire energy from the sun – a clean source. Just get off the grid and lessen carbon footprint by 50% or more. Also, you are saving on the non-renewable energy sources. You will leave a cleaner, greener earth for your grandchildren.

The second advantage is you increase your property value. Now that your home has become more energy-efficient, the resale value of your home will be more. Your home value is to increase by almost $20 for every $1 saving in the annual utility bill as is predicted by the National Renewable Energy Laboratory (NREL).

Solar water heaters work without creating any noise or minimal noise.

When you opt for this greener energy solution, you will earn tax credits which will help in lowering your upfront cost and some local governments also dole out incentives to offset a part of your initial investment.

 

 

With it’s increased popularity, Solar bug zappers have been more popular among people looking for a tool to minimize the presence of mosquitoes and other flying insects in their backyards. The reason for it’s increased popularity is because solar-powered bug zappers don’t use any chemicals or aromatic oils. They don’t emit any fumes, smells or other smoke and work in an environment-friendly way to convert sunlight into electricity via the solar panels attached to them.

But this popularity has made it difficult to choose the best one. Which is the best solar bug zapper in 2020? If this is the question for which you have been looking to get an answer, read this article for the solution.

LIGHTSMAX Solar Powered Bug Zapper

LIGHTSMAX Solar Powered Bug Zapper

This is both a powerful zapper and an attractive garden lamp which will allow you to enjoy a bug-free garden no matter the time of the day.

With just the exposure to sunlight in the daytime, it will light up your garden during the night and keeps the bugs and mosquitos away. Once it is fully charged during the daytime, it will be able to last through the night. It is the perfect eco-friendly and reliable alternative lighting.

Another thing that is great about this is its multi-functionality. Not only can it zap the bugs when you are outdoors and doubles as garden light in the night the included handle makes it easy and portable to take it anywhere like for fishing, camping, hiking or any other outdoor activity to keep the pesky bugs away. The beautiful modern design of this light is also ideal for additional decoration for your outdoors.

Read more about the Lightsmax solar bug zapper here.

GutReise Solar LED Lamps and Bug Zapper

GutReise Solar LED Lamps and Bug Zapper

It has purple UV rays that can attract and lure insects, including moths, flies, and mosquitoes and zap them. This is a great lamp to make an insect-free space without using harmful sprays and pesticides both indoors and outdoors.

It is also a good choice for places like hospitals and other places where you absolutely cannot use a chemical spray. In addition to being a good insect zapper, it is, of course, a decorative light too.

You can also save energy with it because it has a power adapter for placing it indoors when needed. Learn more about it and read the customer feedback here

Two in 1 Waterproof Solar landscape spotlight and Bug Zapper

Two in 1 Waterproof Solar landscape spotlight and Bug Zapper

The Lixada bug zapper solar light comes with a variety of options. You can choose to purchase 2 pieces with hooks or one without a hook. You can also choose the model that also serves as a solar landscape spotlight.

It comes with two light modes. Use the white light option for garden light while the purple light option will attract the bugs and kill them. The modes can be switched by using the button located at the base of the light.

It is also equipped with a light-sensing system that will automatically turn the light on when the sun goes down and evening sets it… It also automatically turns off at dawn and starts charging for the next use. Read more about it here.

I hope this article has provided you with the answer to your question which bug zapper is the best choice for 2020. Get one of the three above and enjoy a bug free evenings in your garden.