How to Choose the Right Solar Inverter for Your Solar Power System (Part 2)

Photo by William Mead from Pexels

There are three types off-grid (also known as stand-alone) solar inverters according to the output waveform of the voltage – pure sine wave, quasi (modified) sine wave, and square wave. 

Pure sine wave inverter has the output waveform of the voltage like a sine wave and this form of electrical output is the same as you will find coming from the utility grid. Modified sin wave inverter has the output waveform not exactly sine wave but it resembles the shape of a sine wave.

Pure sine wave inverter has many advantages over modified sine wave inverter. Pure sin wave inverters can run all electrical home appliances effectively. They are necessary for sophisticated electronics, like a fancy new television or gaming console, fluorescent lights and dimmers, inductive loads like microwave ovens. Pure sine wave inverter keeps appliances safe and more durable. 

Modified sine wave inverter is inexpensive but has a serious disadvantage: it is not compatible with all appliances and may create excessive heat in appliances which will reduce their lifetime. Also, modified sine wave inverters create more noise and a high electrical surge can lead to malfunctioning of home appliances. Modified sine wave inverter is suitable for simple systems or a DIY emergency solar kit, or a cabin with modest electrical needs. They work best with older TVs, incandescent lights, motors with brushes. Generally, they are not good with modern electronics, audio, induction motors, rechargeable batteries, or digital clocks.

The square wave inverter has the output waveform of the voltage like a square wave. This type of inverter is least used among all other types of inverter because all appliances are designed for sine wave supply. If we supply square wave to sine wave-based appliance, it may get damaged or losses are very high. The cost of this inverter is very low but the application is very rare. It can be used in simple tools with a universal motor.

Off-grid inverters are not connected to the electrical utility grid and they are designed to be integrated with a battery bank. The off-grid inverter draws power from the battery and converts it from DC power from the solar panels into AC power. The off-grid battery inverter only discharges the battery (unlike an inverter/charger). When the batteries’ charge level gets below a threshold, the inverter will shut down to protect both home appliances and the batteries.

In an off-grid system, PV panels charge the batteries via a charge controller, and only the power demanded by the loads is inverted to AC. These systems do not have access to the electrical utility grid so it is important to properly size the inverter as well as the battery bank.

The battery inverter/charger combines the functionality of a DC/AC battery inverter and a battery charger. Like any inverter, an inverter/charger converts DC (battery) power into AC power but it will also charge (converting AC into DC energy) the attached batteries when an AC power source is present. Generally, they are designed for applications in which AC power will be available from an outside source, such as a generator or shore power. Besides, in an off-grid solar power system, they are also used in a boat or a RV. 

Some advanced models of inverter/chargers (multi-mode, bi-directional) can charge a battery, converting AC power from the utility grid to DC power, and also feed power back into the grid using net metering, similar to the grid-tie inverters. If there is a power outage, the inverter/charger will automatically switch to battery power to provide power to connected equipment. 

A hybrid solar system is connected to the electrical utility grid and also has a battery bank. Hybrid inverters combine a standard solar inverter and a battery inverter/charger in one simple unit. Hybrid inverters convert the DC power your solar system generates into AC power, which can be used to power your home appliances or fed directly into the grid. The hybrid inverter can also manage inputs simultaneously from the solar panels and a battery bank. The batteries are charged with either solar panels or the electricity grid, depending on which is more economical or preferred.

Not all hybrid inverters provide battery backup in the event of a blackout. A basic hybrid inverter cannot supply power when there is a blackout (commonly known as an uninterruptible power supply or UPS function). There is another type of hybrid inverters so-called multi-mode inverters with backup power capability during a blackout, which are more advanced hybrid inverters designed to work in on-grid mode and off-grid mode for a long time.

A grid-tied solar power system will not power your home during a blackout, so in areas where blackouts and weather-related outages are common, a hybrid solar power system with a multi-mode hybrid inverter may be a solution. You can also buy a hybrid inverter for your grid-tied solar system if you plan to add batteries soon and this is the most cost-effective option. 

The modern hybrid inverters are more versatile than grid-tie and off-grid inverters, and they are also more expensive. The advantage of hybrid solar inverters is that they allow the centralised monitoring of the solar array. Thus, the homeowners only have to check on one portal to understand how much energy their solar panels are producing and how the batteries are performing. 

You can always add storage to an existing grid-tied solar power system later and it is still the common practice as the homeowner already has a grid-tie inverter installed. However, a disadvantage of this method is the higher cost. 

Another option is by adding an AC coupled battery system such as the Tesla Powerwall 2 and Sonnen ECO (they have built-in inverter) to your grid-tied solar system. These battery systems can be retrofitted to a home with an existing solar power system and grid-tie solar inverter. They are expensive but they are also the best in the market.

See also: How to Choose the Right Solar Inverter for Your Solar Power System (Part 1)

How to Choose the Right Solar Inverter for Your Solar Power System (Part 1)

Photo by Alex Csiki from Pixabay

The solar inverter converts direct current (DC) electricity generated by your solar panels into usable alternating current (AC) electricity used by household appliances. If you have decided to go solar and install solar power system for your home, you have to do some research and have an initial knowledge about the solar inverter. 

The solar inverter consists of complex power electronics and software and it is crucial to the performance of your solar power system. When you choose your solar panels for your home it is important also to consider buying the right solar inverter for your solar power system. In this post, I’ll give you some basic information about solar inverters, their types, how they work, the best brands, and how to size an inverter to be right for your solar power system.

There are three groups of solar inverters: grid-tie, off-grid, and hybrid. There are three main types for grid-tied solar power systems: string inverter, microinverter, and string inverter + power optimizer. 

String inverters are central inverters and they are the most commonly used inverters for home solar power systems. When few solar panels of the same output voltage and power are wired together in series we have what is known as a "string”. All of the energy the panels produce is sent to a single inverter that is typically located on the side of your house, garage or utility room. String inverters are easy to install and maintain, and they also have the lowest price. 

This type of inverter is suitable when your panels are not facing multiple angles and have no shading issues. The disadvantage here is that if one panel is in shade and suffers reduced output, every panel in the string drops to that reduced output. 

Microinverters are small devices also known as module-level power electronics (MLPEs) that are attached directly to each solar panel, usually on the back. Thus they need to be designed to be resistant to humidity and heat. Microinverters convert DC power to AC right at the panel, providing a better performance of the solar array thus better performance of the whole solar power system. Just make sure the microinverter capacity matches that of the solar panel.

Microinverters allow you to monitor individual panel performance, giving you a more clear view of efficiency. Also, if something goes wrong with a particular solar panel, you can fix it easily. Because of all of this, and the need for multiple inverters, microinverters are the higher cost option. Besides that, another disadvantage is that they are located on the roof, so their maintenance is complicated. 

Power optimizers are small devices as well that is located on the roof alongside or integrated with each solar panel, allowing for more accurate performance monitoring. But unlike microinverters, they don’t convert power from DC to AC directly. Instead, they simply “optimize” the DC electricity before it is sent to a string inverter for conversion into AC. 

Power optimizers, similar to microinverters, make the solar energy system more efficient, but you can buy them at a more affordable price. And like microinverters, maintenance and repair cost power optimizers are high with power optimizers given their rooftop location. Microinverters and power optimizers typically come with a 20 to 25-year warranty while standard inverters typically have 12 to 15-year warranties.

Microinverters and power optimizers (together referred to as module-level power) are gaining popularity in residential solar markets. It’s always nice to have options, and string inverters and MLPEs each have pros and cons. 

The three best string solar inverters for 2020 are: Fronius (Primo and Galvo), SolarEdge (SE and HD wave), SMA (Sunny boy series). Enphase is a leading manufacturer of microinverters.

The inverter sizing refers to choosing the right size of solar inverter for your solar power system. As a general rule of thumb, you’ll need an inverter that matches the watts of your solar panel installation, For example, if you have a 3kW solar panel system, then you would install a 3kW inverter. In the case of microinverters, the size of the inverters should correspond to the energy output of each solar panel they’re connected to versus the entire system. 

If you plan to go off-grid, to choose the right inverter for your solar power system you must calculate the load your inverter can handle. You should know that inverters are rated in continuous/running watts and surge/peak watts. It’s important to consider both the continuous load and surge load when it comes to inverters (inverters have two capacity values printed on the manufacturer’s label: continuous watts and surge watts).

Surge watts are the amount of power the inverter can support for a very short time, usually no longer than a second when the appliance starts up. Appliances with motors require about 1.5 to 2 times the running wattage before the motor will start. Appliances and tools with induction motors such as refrigerators, freezers, air conditioners, microwave ovens, and pumps, need a much higher power level at startup. They may require a start up surge of 3 to 7 times the continuous rating.

Find out the appliance’s description and read the specific wattage requirements. If the wattage of the appliance is not listed on the specification, you may calculate the standard watts each of your appliances requires using the formula:

Amps x Volts = Required Watts

For example, if you have a microwave 7.5 amps x 120 (using a 120-volt ac) = 900 watts. It means that the inverter has to handle both the 900 running watts and the 2,700 watts surge requirements of your microwave. 

If the running wattage of your fridge is indicated as 600 watts, the surge wattage will be about 1,800 watts, but this surge is needed for only a fraction of a second. To run this refrigerator, you will need an inverter that can handle 600 running wattage and a surge of about 1,800 watts for a split second. At discount stores or home centers, you can find a typical inverter that provides 1,500 watts of continuous power and 3,000 watts of surge power. https://homeguides.sfgate.com/run-refrigerator-inverter-49672.html

For your inverter to be right for your system, its surge watts rating must be approximately equal to (or greater than) the potential surge watts of each appliance. You can find this out by looking at the label on the back of all of the appliances.

If you want to use multiple house appliances at the same time use the appliances running and surge wattage to determine which devices you can run simultaneously. Just add up all the continuous watt ratings of all the appliances that may be running simultaneously. The sum of continuous watts you get will determine if you're inverter can handle it. Always keep the running load under the maximum limit of your inverter.

With an inverter, with a continuous rating of approximately 1500 watts and with a surge rating of approximately 3000 watts, you can run a wide range of household appliances simultaneously by managing the running load. You can run LED lights, TV, stereo, laptop, fans, fridge, and a microwave (depending on the wattage) at the same time. Just put a current display meter to check the running load before you switch on a new appliance.

It is also recommended to provide a safety room of 10% - 20% watts (more than your largest load) when sizing up an inverter.

Remember: always seek professional help for the installation of your solar power system because of the specific power needs and circumstances of every home.

Next post: How to Choose the Right Solar Inverter for Your Solar Power System (Part 2)

Sources: unboundsolar.com, altenergy.org, homeguides.sfgate.com, batteryspace.com 

Why Now is the Right Time to Switch to the Solar Powered Lifestyle

(Guest post by Rich Feola)

Have you found yourself intrigued by the thought of switching your home’s energy power to solar? It is sure to have crossed every homeowner’s mind as solar energy growth exploded during the past decade. In the United States, it remains one of the top two renewable energy sources with no sign of slowing down. 

The exponential growth in the solar industry is proof that millions of homeowners have discovered the benefits of solar energy. Yet others are in the same boat as you and hesitant to make that switch. 

However, when you realize the shift away from traditional power sources means you are not only bringing down your electric costs but also decreasing your effect on nature’s domain, the decision to go solar becomes an easy one. Let’s review just a few benefits you will see when you invest in solar solutions for your home.

Lower those soaring utility costs.

I am from Las Vegas where the sun is always shining and air conditioning is a must. You wouldn’t believe the astonishing advantages of solar energy. Unfortunately, many homeowners are oblivious to just how beneficial solar power could be to their life. 

One of the most clear-cut benefits of solar panels is the ability to hedge utility prices. According to the Energy Information Administration, the average United States resident used roughly 10,649 kilowatt hours in 2019 at a cost of around $1,950 dollars for the year. 

You will begin experiencing savings on those high utility costs the minute your solar panels are installed. Holding off any longer means you are stuck paying those extreme electric costs each month. If you pull the plug now, that is an extra $1,950 you could have in your pocket this time next year.

But the most important factor is how electricity rates rise each year by an average of 6%. This means that your energy bill will cost you double in ten years’ time! If you had invested in solar ten years ago, your own personal power plant would have saved you tens of thousands and you wouldn’t have to worry about the rising cost of electricity on the grid. In fact, many states and local utilities even pay you a credit for the extra energy you produce and transfer to the grid through solar energy.

It should be noted there are a number of variables that will determine the total financial returns you can expect from solar during its lifetime, but with a high quality photovoltaic solar system in place, whatever those costs are will be lowered significantly as your home uses an environmentally friendly way to power itself each day. 

If utility prices continue to rise as expected, those savings will do nothing but surge as time goes on. Going solar is the only way to help protect against these unpredictable increases.

Take advantage of incentives.

Today’s market is experiencing a progressive government attitude towards solar energy, which has resulted in attractive solar power tax rebates at both the federal and state levels. 

In addition to significant tax credits and rebates in place to encourage homeowners to go solar, the installation cost of panels has significantly dropped. As the government continues to incentivize the continued growth of the solar industry, it is important to take advantage while you still can. 

In other good news for today’s shoppers, it costs roughly 70 percent less than it did a decade ago to install a residential solar energy system. Combined with the rebates, your total costs could be potentially cut in half making it the perfect time to use photovoltaic technology. 

There also are an abundance of financing options available if you don’t have the funds for an upfront purchase. If you don’t have the money on-hand, there is most likely a financing option suited just for you, which means you don’t have to outlay any cash upfront for the switch to solar energy.

Reduce your carbon footprint.

Solar energy is clean energy, and I don’t think it is reaching to assume we all want that. Solar systems use pure energy from our sun, helping to combat gas emissions and reduce our collective dependence on fossil fuel. Solar panels absorb D/C current from the sun and convert it to A/C electricity through an inverter which is included in your installation.

Did you know solar can reduce your home’s carbon footprint by more than 3,000 pounds annually? That equals 15,000 pounds of CO2 each and every year. That’s pretty amazing.

Solar panels protect your home, too.

While solar panels are busy helping out the environment, they also protect your home. They start at the very top of your house by extending the life of your roof as it shields it from harmful elements like snow, ice, rain and debris. Likewise, it absorbs the sun and keeps it from beating down on the roof directly. 

Homebuyers also know they have struck gold when they come across a home for sale with solar panels, which increases your value. This provides you a large return on your investment if you ever decide to sell your home. Many local real estate markets see an increase of a home’s value by as much as $26,000 if a solar system is intalled.

As awareness has increased on the importance of reducing our carbon footprint on the environment and financing options have become more readily available, the solar market continues to increase, but is it the right choice for your family? 

Only you can answer that question, but doing research on how solar energy works and the science behind it will help you feel confident in your investment. There is an abundance of information on the long-term benefits of solar on platforms such as YouTube for homeowners ready to go solar. 

It also is important to find the right company. I know from helping solar companies in 39 states that finding the right one for you will pay off in great rewards both environmentally and financially.

Rich Feola is the Founder of the Solar Exclusive, an 8-figure advertising company that generates unique, qualified leads and appointments for solar companies. Solar Exclusive works with solar companies in over 39 states. Rich’s work has been featured in Digital Journal, Yahoo Finance, NBC and Fox among other publications. Want to skyrocket the success of your solar business with top-notch leads? Visit this link to find out more: https://solarexclusive.com/. 

SmartFlower Solar Power System - an Alternative to Solar Panels

Image credit: smartflower.com

SmartFlower solar power system comes from Austria. It is an innovative and unique solar panel system that can be mount on the ground in your backyard. This high-tech “smart” solar power system is an alternative to rooftop mounted solar power systems.

When you install a conventional solar panel system you have some limitation like roof type and space availability while with the SmartFlower solar power system you only need to choose the place which has sufficient exposure to sunlight. Another advantage is that this portable solar panel system shaped like a flower, can follow the sun throughout the day and this is a far more efficient way of harnessing solar energy. The photovoltaic device does all of this autonomously through algorithm-based dual-axis tracking. Thus, SmartFlower can produce up to 40% more solar energy than a conventional solar panel system.

SmartFlower solar power system has a stunning design and some cool high-tech features. Its height is 16.4ft (5 meters), weighs around 650 kg, and it rotates throughout the day in the same way as sunflower petals do. The “smart” photovoltaic system occupies 194 square feet. It consists of 12 “petals” covered with solar cells, which open up every morning when the sun rises. The SmartFlower moves toward the sun at a 90-degree angle and produces approximately 2.5kW of electricity in peak sunlight conditions. When the sun goes down the petals close. 

The SmartFlower gathers information about weather conditions and takes it into account when decides whether it should be open or fold together for protection. In winds 29 mph+ the SmartFlower solar petals automatically move to a horizontal position. At 39 mph+, the solar petals will completely fold down. Also, the solar petals clean themselves through the anti-microbial brushes that are attached on the back of each petal.

The upgraded model of the SmartFlower is named SmartFlower +Plus. SmartFlower +Plus is the same as the main version but includes battery storage to store solar energy. The stored excess solar energy can cover cloudy days and peeks in consumption. SmartFlower +Plus can work on-grid and off-grid - completely independent from the grid. This model is available in two versions –one with a storage capacity of 4.6 kWh and the other with 13.8kWh storage capacity. In addition, there is another model of the SmartFlower that lets you charge electric cars. 

Besides tracking the sun and self-cleaning, other “smart” features are self-containing and self-cooling. The SmartFlower solar power system is an all-in-one complete solar energy system, with an inverter, battery storage, battery charger, monitor, and control box, all integrated into a single unit. SmartFlower solar system also has rear ventilation to keep the system up to 18°F cooler than it would be without it. That is good for solar cell efficiency, which means 5-10% more output on average.

The SmartFlower is available in eight colors (berry, ocean, amber, mermaid, pearl, lavender, jungle, and porcelain). It can be fast and easily installed (just plug and play). And by removing four bolts and one cable you can move SmartFlower anywhere you want.

According to the news, the Austrian manufacturer of the SmartFlower began bankruptcy proceedings in Germany in 2017. However, the U.S. division of SmartFlower operates independently from the original Austrian developer. So far, the SmartFlower has been installed at numerous U.S. backyards, in addition to organizations like the Detroit Zoo, Mary Baldwin University, and Virginia Wesleyan University. The United States division of SmartFlower is currently based in Boston, Massachusetts.

SmartFlower solar power system is a real alternative to solar panels. If you want to buy one of the models, you should know that before applying for all incentives and tax credits, the SmartFlower solar panel system ranges from $25,000 to $30,000. SmartFlower can generate between 4000 and 6500 kWh per year. The average home in the United States uses 10,400 kWh annually, so this will cover 40-60% of your energy bill.

You can visit the official SmartFlower website for more information.

Sources: solar.com, energysage.com & Internet