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How Many Solar Panels Do You Need: Panel Size and Output Factors. Pv array power

How Many Solar Panels Do You Need: Panel Size and Output Factors. Pv array power

    This Is How Many Solar Panels You Need to Power Your House

    This formula will tell you how many solar panels are needed to meet 100% of your home’s energy demand.

    Jackie Lam is a contributor for CNET Money. A personal finance writer for over 8 years, she covers money management, insurance, investing, banking and personal stories. An AFC® accredited financial coach, she is passionate about helping freelance creatives design money systems on irregular income, gain greater awareness of their money narratives and overcome mental and emotional blocks. She is the 2022 recipient of Money Management International’s Financial Literacy and Education in Communities (FLEC) Award and a two-time Plutus Awards nominee for Best Freelancer in Personal Finance Media. She lives in Los Angeles where she spends her free time swimming, drumming and daydreaming about stickers.

    • She is the 2022 recipient of Money Management International’s Financial Literacy and Education in Communities (FLEC) Award and a two-time Plutus Awards nominee for Best Freelancer in Personal Finance Media.

    Taylor Freitas is a freelance writer and has contributed to publications including LA Weekly, Safety.com, and Hospitality Technology. She holds a B.A. in Print and Digital Journalism from the University of Southern California.

    Chi Odogwu is a digital consultant, professor, and writer with over a decade of experience in finance and management consulting. He has a strong background in the private equity sector, having worked as a consultant at PwC and a research analyst at Renaissance Capital. Additionally, he has bylines in well-known publications, including Entrepreneur, Forbes, NextAdvisor, and CNET. He has also leveraged his writing talent to create educational email courses for his clients and ghostwritten op-eds published in top-tier publications such as Forbes, CoinDesk, CoinTelegraph, Insider, Decrypt, and Blockworks. In addition to his writing, education, and business pursuits, Chi hosts the top-rated Bulletproof Entrepreneur Podcast. Through this podcast, he engages in insightful conversations with talented individuals from various fields, allowing him to share a wealth of knowledge and inspiration with his listeners.

    High inflation and the soaring costs of power bills can make powering your home with solar energy quite appealing. And if the allure of going green and saving money has you wanting to go solar, you’ll need to figure a few things before the installer swings by. For one, the number of solar panels to adequately meet your home energy needs.

    A common misconception is to gauge how much bang for your buck you’re getting purely based on wattage, says Courtney Corda, co-founder of the California-based solar company Corda Solar. Knowing how many panels you need isn’t just about wattage, but the costs involved in installing, panel performance, location and your usage needs, Corda explains.

    Here’s how to figure out how many panels can support your energy needs and what other factors can interfere in your production goals.

    Can solar panels save you money?

    Interested in understanding the impact solar can have on your home? Enter some basic information below, and we’ll instantly provide a free estimate of your energy savings.

    How to calculate how many solar panels you will need

    To get a realistic estimate of how many solar panels a home might need, we turned to Jake Edie, an adjunct professor at the University of Illinois Chicago. Edie provided us with a straightforward calculation method.

    If you’re curious about how many solar panels your home might require, here’s how you can figure it out, Edie says. Let’s say your household uses 1,500 kWh of electricity each month. Here are the steps to calculate the solar panels you’ll need.

    Can solar panels save you money?

    Interested in understanding the impact solar can have on your home? Enter some basic information below, and we’ll instantly provide a free estimate of your energy savings.

    many, solar, panels, need

    Step 1. Review your monthly electric bill: It’s important to determine how many kilowatt-hours of electricity you consume monthly. In this example, this particular home uses 1,500 kWh every month.

    Step 2. Convert monthly energy use to daily use: Given 1,500 kWh is consumed per month, to ascertain the daily usage, we need to divide this figure by the average number of days in a month, which is roughly 30.42 days (365 days divided by 12 months).

    Hence, the average daily use = 1,500 kWh / 30.42, approximating 49.3 kWh daily.

    Step 3. Determine peak sunlight hours: This factor varies based on location and climate. For this example, let’s assume that this home receives an average of about five peak sunlight hours per day.

    To calculate the total daily energy production required, divide the daily energy consumption by the number of peak sunlight hours. This gives the amount of energy your solar panels need to produce per day.

    Energy production required = 49.3 kWh per day / 5 hours, which equals 9.86 kW.

    Step 4. Calculate the number of panels: Lastly, you’ll need to determine the wattage of the solar panels you plan to install. The average solar panel in the US is rated between 250 and 400 watts. For this example, we’ll assume the selected solar panel has a rating of 350 watts.

    By dividing 350 by 1,000, we can convert this to kilowatts or kW. Therefore, 350 watts equals 0.35 kW.

    To determine the required number of solar panels, we must divide the daily energy production needed by the solar panel’s power output.

    Number of solar panels required = 9.86 kW / 0.35 kW per panel, which equals 28.17 panels.

    This homeowner will need approximately 29 solar panels to generate enough electricity to match their current usage from the municipal electric company. While this calculation may seem straightforward, there are many factors that can affect the effectiveness of solar panels, such as shading, roof orientation, and seasonal variations in peak sunlight.

    It is highly recommended that you seek the guidance of a professional solar installer who can assess your circumstances and provide a tailored solution to meet your needs.They should be certified from the North American Board of Certified Energy Practitioners, which is the solar industry standard. CNET also has a well-researched list of best solar companies.

    Other factors that affect how many solar panels you need

    There are a variety of factors to take into consideration that will help you and an installer determine how many solar panels you need to power your home. Here is a breakdown:

    Solar panel wattage

    One big part of a solar panel’s performance is its wattage and will affect how many panels you need. The higher the wattage, the more power a panel can generate.

    Most residential solar panels have ratings of 250 to 400 watts. The most efficient solar panels on the market are 370 to 445-watt models. The higher the wattage rating, the higher the output. In turn, the fewer panels you might need.

    For example, you might buy a solar panel with a listed output of 440 watts. You’ll need to multiply the panel’s wattage by how many hours of sun you get every day to understand how much energy it will produce.

    If you don’t have much space, you might want to invest in solar panels with higher efficiency and wattage ratings since they’re equipped to generate more energy per panel. But they’re also more expensive, so bear that in mind if the solar budget for your home is tight.

    Output efficiency

    If your roof has limited space for panels, you’re going to want to get the most performance per square inch of panel that you can, explains Corda.

    many, solar, panels, need

    Scientists and technical developers of solar panels have been working hard for decades to try to make each solar cell on the panel able to convert more of the sun’s light to electricity than before, or to make them more efficient, says Corda.

    As she explains, currently, the most efficient panels on the market have anywhere from 18% to 22.8% efficiency, with most panels hovering around 20% efficiency. So the higher the efficiency, the fewer solar panels you might need.

    In reality, a more efficient solar panel will require fewer panels overall for your home, assuming all other factors are equal.

    Production ratios

    A production ratio for solar panels helps you determine how much energy you can get from a panel. The production ratio, or performance ratio, is an important measure of the effectiveness and efficiency of a solar system. It compares the actual output of the system to the output it would produce under ideal conditions. This ratio takes into account factors that reduce output, such as temperature, dust, snow, shade, aging of the panels and inefficiencies in the inverter.

    The performance ratio is expressed as a percentage, with a higher ratio indicating that the PV system is producing a greater percentage of its theoretical output. For example, a performance ratio of 80% means that the system is producing 80% of its rated output in real-world conditions. The higher the production ratios, the fewer panels you might need.

    Panel size

    There are three main sizes for solar panels: 60-cell, 72-cell and 96-cell. The 60- and 72-cell panels are more common for residential installations are generally about 3 by 5 feet, or 15 square feet.

    Where you live and hours of sunlight

    The more hours of sunlight your roof is exposed to, the fewer panels you’ll probably need to install. This is based on the direction, pitch and orientation of your roof, the weather and how much shade covers the roof. It also depends on the time of year and where you live.

    In the winter [the solar panel] produces less than in the summer. So your energy production from solar will change throughout the year and then the usage within your home will change depending on what appliances are using electricity, says Justin Draplin, CEO of Eclipse Cottages, a sustainable home technology and development company.

    So if you live in a really hot climate, then during the summer months, your electrical bill is going to be a lot higher to cool your home versus if you’re in a cold environment, your electrical bills are going to be a lot higher in the winter.

    How much shade your roof gets always plays a factor in how many solar panels you’ll need for your home, Corda says. If your roof is covered by large oak trees or a chimney and gets a lot of shade, this will bump down solar panel output. In turn, you might need more panels to power your home. But if your roof doesn’t get much shade, your solar output will be higher for the same space.

    Roof type and condition

    The orientation, angle, shape and type of roof will affect the number of panels you can reasonably fit into a given area, explains Corda.

    A home without a complicated roof structure, pitched at a 10 degree angle and south-facing is best for solar panels.

    That would be an ideal roof for solar because you’ve got it tilted, it’s facing south, and the pitch of the roof is neither flat nor very steep, which is ideal for putting panels on there to capture as much energy from the sun as possible, says Corda. A house with a more complicated roof structure won’t be able to fit as many panels, she adds. For instance, Spanish tile-roofs are considered solar unfriendly and require special attachments.

    Cost and budget

    While powering your home on solar energy can save you money, it does require a serious investment upfront. The costs to power your home on solar and your budget will determine how many solar panels you can afford.

    Currently, the average cost for a home solar panel system is around 3 per watt, according to data from the research firm Wood Mackenzie. Based on this figure, an 8-kilowatt sized system would be 24,000 before any tax breaks or incentives kick in.

    Whether you are paying cash or financing, knowing what you can afford will play a factor in how many panels you add to your home.

    Annual electricity usage

    To know how many panels will meet your energy demand, you’ll need to know your annual energy usage. You can log onto your account online, review statements, you’ll see how many kilowatt hours of electricity you use. You’re going to want to look at your patterns over the course of a year.- if not the last couple of years, says Corda.

    Once you have that number, you’ll know how much solar power you need to generate to cover your needs.

    Besides recent use, factor in the future energy needs, Corda points out. For instance, do you anticipate purchasing an electric vehicle? Or do you plan on growing your family? Or are you and your spouse going to be working from home more? If so, then your energy needs will go up in the future years. On the flip side, if your teens will soon leave the nest to go to college, then you can expect your energy usage to taper off.

    Your personal solar goals

    Determining your personal solar goal is figuring out what you want to achieve with your solar panel addition. Living completely energy independent and off the grid would mean more solar panels. If you want to power your whole house, you have to really oversize it to make sure you have enough power in the winter, even though you’re going to be over producing in the summer, says Draplin.

    Adding battery storage will also play a factor in how many panels you need. With solar battery storage, you can essentially bank energy and store it for later use when you’re producing excess energy.

    If your goal is to lower your energy bill or reduce your carbon footprint, then maybe you won’t need as many panels, says Draplin.

    Figuring out the number of solar panels you need is only part of the equation. Learn more about the benefits and costs of home solar from CNET:

    Solar panel FAQs

    Can I run my house on solar power only?

    The simple answer is: Yes, you can power a house entirely on solar power. To meet your energy ends, you’ll want to factor in a handful of variables: the size, pitch and orientation of your roof, the size of panels you’d like to install, the amount of shade, output efficiency and wattage. Plus, you want to figure out current and future usage needs, and whether you want your entire home to be powered on solar energy or just part of it.

    How Many Solar Panels Do You Need: Panel Size and Output Factors

    How many solar panels does the average house need? How many solar panels do I need for a 3-bedroom house? How many solar panels do I need for a 2000 sq. ft. home? These are all common questions for an aspiring solar homeowner. Determining how many solar panels you’ll need for your home requires first knowing what your goals are.

    Do you want to minimize your carbon footprint? Maximize the return on your investment? Save as much money as possible?

    Most people want to save money while minimizing their environmental impact.

    To calculate how many solar panels you need, you need to know:

    • Your average energy requirements
    • Your current energy use in watts
    • The climate and amount of sunlight in your area
    • The efficiency of the solar panels you’re considering
    • The physical size of the solar panels you’re considering

    One simple way of answering the “How many solar panels do I need” question is to consult a professional solar installer, who can give you a free home solar evaluation.

    How much solar power will you need?

    To determine your home’s average energy requirements, look at past utility bills. You can calculate how many solar panels you need by multiplying your household’s hourly energy requirement by the peak sunlight hours for your area and dividing that by a panel’s wattage. Use a low-wattage (150 W) and high-wattage (370 W) example to establish a range (ex: 17-42 panels to generate 11,000 kWh/year). Note that the size of your roof and how much sunlight your roof gets are factors as well.

    If you work with an experienced solar installer, they will handle all these calculations for you. If you’re searching for a calculator to figure out “how many solar panels do I need?”, look no further. You can use SunPower Design Studio to estimate your own system size, monthly savings, and the actual appearance of a solar array on your own roof. This interactive tool provides a solar estimate in just a few seconds and can be done on your own or on a call with SunPower (800) 786-7693.

    How many watts do you currently use?

    Look at your electricity bill for average usage. Look for “Kilowatt Hours (or kWh) Used” or something similar, and then note the length of time represented (usually 30 days). If your bill doesn’t show kilowatt hours used, look for beginning and ending meter readings and subtract the previous reading from the most recent one.

    You want daily and hourly usage for our calculations, so if your bill doesn’t show a daily average, just divide the monthly or annual average by 30 or 365 days, respectively, and then divide again by 24 to determine your hourly average electricity usage. Your answer will be in kW. (And just in case you’re wondering, a kilowatt-hour is how much power you are using at any given time multiplied by the total time the power is being used.)

    A small home in a temperate climate might use something like 200 kWh per month, and a larger home in the south where air conditioners account for the largest portion of home energy usage might use 2,000 kWh or more. The average U.S. home uses about 900 kWh per month. So that’s 30 kWh per day or 1.25 kWh per hour.

    Your average daily energy usage is your target daily average to calculate your solar needs. That’s the number of kilowatt-hours you need your solar system to produce if you want to cover most if not all of your electricity needs.

    It’s important to note that solar panels don’t operate at maximum efficiency 24 hours a day. (See Solar 101: How Does Solar Energy Work?). Weather conditions, for example, can temporarily reduce your system’s efficiency. Therefore, experts recommend adding a 25 percent “cushion” to your target daily average to ensure you can generate all the clean energy you need.

    How many hours of sunlight can you expect in your area?

    The peak sunlight hours for your particular location will have a direct impact on the energy you can expect your home solar system to produce. For example, if you live in Phoenix you can expect to have a greater number of peak sunlight hours than if you lived in Seattle. That doesn’t mean a Seattle homeowner can’t go solar; it just means the homeowner would need more panels.

    The Renewable Resource Data Center provides sunlight information by state and for major cities.

    Now multiply your hourly usage (see question No. 1) by 1,000 to convert your hourly power generation need to watts. Divide your average hourly wattage requirement by the number of daily peak sunlight hours for your area. This gives you the amount of energy your panels need to produce every hour. So the average U.S. home (900 kWh/month) in an area that gets five peak sunlight hours per day would need 6,000 watts.

    What affects solar panel output efficiency?

    Here’s where solar panel quality makes a difference. Not all solar panels are alike. Photovoltaic (PV) solar panels (most commonly used in residential installations) come in wattages ranging from about 150 watts to 370 watts per panel, depending on the panel size and efficiency (how well a panel is able to convert sunlight into energy), and on the cell technology.

    For example, solar cells with no grid lines on the front (like SunPower ® Maxeon ® cells) absorb more sunlight than conventional cells and do not suffer from issues such as delamination (peeling). The construction of our cells makes them stronger and more resistant to cracking or corrosion. And a microinverter on each panel can optimize power conversion at the source, in contrast to one large inverter mounted on the side of the house.

    Because of these wide variations in quality and efficiency, it’s difficult to generalize about which solar panels are right for you or how many you’ll need for your home. The main takeaway is that the more efficient the panels are, the more wattage they can produce, and the fewer you will need on your roof to get the same energy output. Conventional solar panels usually produce about 250 watts per panel, with varying levels of efficiency. In contrast, SunPower panels are known to be the most efficient solar panels on the market.

    To figure out how many solar panels you need, divide your home’s hourly wattage requirement (see question No. 3) by the solar panels’ wattage to calculate the total number of panels you need.

    So the average U.S. home in Dallas, Texas, would need about 25 conventional (250 W) solar panels or 17 SunPower (370 W) panels.

    What is the effect of solar panel size?

    If you have a small or unusually shaped roof, solar panel size and numbers are important considerations. With a large usable roof area, perhaps you can sacrifice some efficiency and buy larger panels (at a lower cost per panel) to get to your target energy output. But if your usable roof area is limited, or if it’s partially shaded, being able to use fewer smaller high-efficiency panels may be the best way to make the most possible power over the long term, ultimately saving you more money.

    Solar panel dimensions

    Typical residential solar panel dimensions today are about 65 inches by 39 inches, or 5.4 feet by 3.25 feet, with some variation among manufacturers. SunPower panels are 61.3 inches by 41.2 inches.

    These dimensions have remained more or less unchanged for decades, but the efficiency and output from that same footprint have changed dramatically for the better. In addition, SunPower designs entire systems to have virtually no gaps between panels and uses invisible framing and mounting hardware to keep the rooftop footprint as tight, efficient, and attractive as possible.

    How much do solar panels weigh?

    If you’re planning on installing a rooftop solar system, understanding the weight of your solar panels is another key factor to consider. Knowing a solar panel’s weight is the best way to be certain that your roof can support a full installation.

    While panel weights vary from brand to brand, most panels weigh about 40 pounds.

    SunPower panels are the lightest of all major brands. with some of our panels weighing as little as 33 pounds. For comparison, at the top end of the range, some conventional panels weigh as much as 50 pounds.

    Summary: How many panels do you need?

    Knowing the answers to the above questions will give you an idea of the ideal number of panels for your electricity generation needs — or at least a realistic range. Next, a professional installer needs to assess your roof architecture, angle to the sun, and other factors to see if and how you’d be able to physically arrange the right number of panels on your roof to achieve your daily energy production goals.

    You should also consider net metering as you’re considering how much money you’ll save and make from your solar system. Net metering is how your utility company credits you for producing excess solar energy when the sun is shining and then lets you draw from those credits when you’re using a conventional power grid at night if you don’t store your excess solar energy in a battery storage system.

    To get started, check out our solar power calculator, which can help you figure out how much you might save going solar.

    Interested in high-efficiency solar panels for your home? Contact SunPower for more information.

    • . Based on datasheet review of websites of top 20 manufacturers per IHS, as of April 2021.
    • . Energy Sage, July 2021, https://news.energysage.com/average-solar-panel-size-weight/

    Pv array power

    The recent environmental awareness triggered governments and private companies around the world to encourage further research and capital investment into the development and deployment of efficient and cost-effective solar technologies. This entry reports on advances in the technological approaches that can be employed to convert sunlight to electricity. This entry presents a short survey of the state-of-the-art architectures of photovoltaic arrays and a review of the concepts and strategies of their associated electronic power processors for solar energy generation.

    Contributor MDPI registered users’ name will be linked to their SciProfiles pages. To register with us, please refer to https://encyclopedia.pub/register :

    Introduction

    The 1921 Nobel Prize in Physics was awarded to Albert Einstein “for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect” [1]. This exciting discovery further inspired humanity’s futuristic dream to harness the sun for free energy. While indeed free and, in some parts of the world, abundant, solar energy is still challenging to capture, store and distribute to users on an economical basis. The primary disadvantages of solar energy generation systems are their intermittent nature, the limited conversion efficiency of commercially available photovoltaic (PV) cells, and the high capital investment. The cost of the solar generation system can be reduced by improving the photovoltaic conversion efficiency so that smaller and cheaper systems can be used. Less hardware, installation, labor, and real estate costs can improve the Total Life Cycle Cost of solar energy [2] and, consequently, increase the penetration of solar energy generation systems into the global energy market.

    The small physical dimensions of a PV cell allow limited amount of solar irradiation to be captured, providing only a minute amount of electrical power. To generate a practically usable amount of energy, a large number of PV cells have to be stacked together to form an array, also referred to as a PV panel or single PV module. Commercially available PV modules are field-installable units, typically 1–3 sq. m in size, which can generate about 150–300 W each. Grid-connected PV generating systems are designed to supply much higher power and require a considerable amount of PV modules to be assembled into a larger PV array [3]. Thus, the PV array is, in fact, an array of arrays composed of a huge number of basic PV cells and has complex wiring. The optimal utilization of such a large ensemble of PV cells is a rather intricate task.

    The primary challenge is posed by the inherent non-linearity of the PV cell, that has a bell shape power-voltage curve with a unique maximum power point (MPP). The MPP is located at the knee of the voltage-current characteristics, where the abrupt slope change manifests the transition from current source behavior towards the voltage source region. Yet, in case of shading or malfunction, the P–V curve may comprise several distinct MPPs. Therefore, to extract the maximum available DC power out of the PV array, an electronic dynamic Maximum Power Point Tracker (MPPT) [4] and a proper power converter/inverter set are required to generate AC at utility compatible voltage level and connect to the grid.

    The wiring of the PV array, the power processing architecture and the MPPT algorithm have a significant effect on how the mismatch and shading affect the power yield of the PV system [5]. Over the years, researchers have extensively experimented with various PV architectures to maximize the energy yield of PV sources and make the system fault-tolerant, forbearing mismatch, and shading problems, while keeping the solution economically viable. To date, a formidable body of theoretical knowledge supported by extensive practical experience has been accumulated [6].

    Static PV Arrays

    To help limit the mismatch and shading effects, the wiring pattern of the PV array has to be considered to identify architecture with sufficient redundancy. Several possible PV arrays’ interconnection schemes were reported early in the literature [7] [8]. These include the Series (S); the Parallel (P); the Series–Parallel (SP); the Series–Parallel–Series (SPS); the Total-Cross-Tied (TCT); the Bridge-Linked (BL); and the Honey-Comb (HC) arrays, illustrated in Figure 1 a–g, respectively. A simple S array can attain high output voltage at low output current while the P array can provide the highest output current, but only at the low output voltage. The S array is also referred to as the string, whereas the P array is the tier. Both S and P arrays have the simplest wiring. The SP array can output both a high voltage and high current, yet it has simple wiring. The SPS array is formed by connecting several short SP sub-arrays in series.

    Figure 1. Common configurations of PV arrays: Series (a); Parallel (b); Series–Parallel (c); Series–Parallel–Series (d); Total-Cross-Tied (e); Bridge-Linked (f); Honey-Comb (g).

    The TCT array is a string of PV tiers and has a simple setup but also the longest wiring. The BL array has its modules interconnected in bridge rectifier fashion and has a rather complex interconnection. The “honeycomb” pattern of the HC array can be revealed when Figure 1 g is “stretched” horizontally. The HC array has the most complex wiring, which is less of a problem for PV modules manufacturers, but can be demanding for constructing large field installations. In the ideal case, SP, SPS, TCT, BL, and HC arrays can all provide the same high voltage and current; however, the merits of these arrays are in their ability to cope with shading conditions.

    The shape of the array’s V –I curve changes when shadows are cast. While P arrays tend to maintain an easier-to-track single MPP, the composite V –I curve of the S array may include several local maxima points [9]. Both occur due to mismatch losses, and losses due to failure in tracking the global MPP the long S and SP arrays are more prone to loss of power than the short SP or short SPS arrays. Short strings controlled individually seem to deliver the most reliable power production [10]. Therefore, increasing tolerance to shading conditions and the maximization of the energy yield of PV arrays necessitates a minimization of string length. This is especially important in an urban environment, such as roof-top and building-integrated PV systems.

    Further comparison of the three popular high-voltage array architectures reveals that the BL array has the best performance under shading conditions, whereas the TCT array was found second best, and SPS is the least tolerant to shading effects [11].

    Variable Structure Arrays

    In normal conditions, the modules of the reconfigurable array are distributed equally in parallel to the tires of the main TCT array—see Figure 2 a. To equalize the energy production of the array under shading conditions, one or more PV modules from the adaptive bank are removed from the strongest tire and relocated in parallel to the weakest tire. The sorting continues until all the modules of the adaptive bank are redistributed, as in Figure 2 b. Partial shading of a particular tire manifests itself by slightly decreased voltage. Therefore, electrically, the objective of the controller is to minimize the differences in voltage measured across the tires. DPVA requires additional hardware and complex sorting and control algorithms to be applied.

    Figure 2. Dynamic PV Array: during uniform insolation conditions (a); reconfigured to compensate for partial shading (b) [12].

    To implement a reconfigurable array having a hard-wired fixed part of TCT array and an adaptive one of independent solar cells, both parts were linked through a controllable matrix of switches [13]. The matrix, see Figure 3. was controlled in real time to connect the cells of the adaptive array in parallel with shaded rows of the fixed one and optimize the output power.

    The principle of the optimized string-configured DPVA (OS-DPVA) [14] is configuring the PV modules into several strings with similar power levels. Each string connects to the dc bus through an MPPT dc–dc converter, as shown in Figure 4 b. The number of strings is determined according to the number of available dc–dc converters. Under these constraints, the controller evaluates the most productive array arrangement for the given environmental conditions. As the string length is unpredictable, the input voltage to the dc–dc converter may vary widely.

    Figure 4. String-Configured Dynamic PV Array (a) [15] ; the Optimized String-Configured Dynamic PV Array (b) [14].

    To optimize the productivity of the TCT array, the authors of [13] suggested reconfiguring the array to equalize tire currents. Since the photocurrent is directly proportional to the irradiation, the method also aims to do this; therefore, it also is referred to as the Irradiance Equalization (IEq). The approach is implemented by relocating modules from the best-performing tire to the weakest one until the IEq is achieved, as shown in Figure 5. The optimum irradiation of a tire can be found by averaging the total irradiation captured by the array per number of tires.

    Figure 5. Illustration of the reconfiguration strategy: initial (a); irradiance equalized (b) [13].

    Power Processing Architectures for PV Arrays

    Another key component of any solar energy generation plant is the electronic power inverter. The inverter’s task is interfacing the solar energy to the grid. This involves maximum power point tracking (MPPT) function to maximize the captured energy, converting the dc voltage obtained from the PV array into AC, and injecting it to the grid in compliance with the high-power quality standards, i.e., at high power factor and minimum harmonic distortion. The inverter’s architecture is concerned with the implementation of a certain operational strategy of a PV array that can maximize its energy output. Four major PV inverter concepts, shown in Figure 6, are the centralized inverter, the string inverter, the multi-string inverter, and the micro-inverter [16]. The centralized inverter system is designed to connect a large SP array to the grid. SP array can provide sufficiently high voltage and high power, that justifies a three-phase grid connection with the additional advantage of reduced dc–ac power decoupling requirements.

    The power loss of a PV string to partial shading can be minimized by applying low-power dc–dc converters, which can “shuffle” power around a problematic module. The converters are wired in overlapping arrangement to shuffle power one level up, as illustrated in Figure 7 [17]. The shuffling converter has to process only the small difference between the powers generated by the adjacent modules. Therefore, while the shuffling converters can significantly increase the power generation under shading conditions, the converter losses have only a marginal effect on the overall system efficiency. However, in the worst case of mismatch, when the PV module has lost most of its generation capacity, the power shuffled by a converter equals that of a PV module so the converter must be rated accordingly. Since the system in Figure 7 is composed of unidirectional converters, it also requires an isolated converter unit to shuffle power from the top to the bottom of the string. The top-to-bottom shuffling unit can be spared when using bidirectional converters such as non-isolated Cuk or buck-boost/flyback converters [18].

    Application of a dedicated converter per each PV module is referred to as Module-Integrated Converter (MIC). MIC is individually controlled by the MPPT controller to extract the optimal amount of available power from each PV module and help to resolve mismatch and shading problems. MICs that are employed as dc–dc converters are referred to as dc optimizers, whereas MICs with a dc–ac inversion capability can be connected directly to the grid and are commonly referred to as micro-inverters. Compared to equalizers, which process only part of the power needed to balance the PV array, MICs process the full power of the array and are at disadvantage. For these reasons, MICs have to exhibit the highest efficiency, whereas the requirements towards the equalizer’s performance are significantly relaxed.

    Sub-Module Power Processing Architectures

    PV modules are pre-wired, field-installable units fabricated in a variety of sizes and rated voltage and power output. To date, the 36- and 72-cell PV modules are the industry standards for large power production [19] [20] [21]. Most commercially available PV modules are configured as a short string of a few, usually three, sub-strings, each having a bypass diode across. Each sub-string is configured as an SP array of macro-PV cells. The incentive to the investigation of sub-module architectures remains increasing the energy yield of a single PV module by reducing the limitations set by mismatch and partial shading. Various approaches developed for string and module levels can also be applied to maximize the power output from each sub-string within the partially shaded PV module. This calls for application of power optimizers, equalizers and MPPT techniques similarly to the described above.

    References

    • The Nobel Prize in Physics 1921. Available online: https://www.nobelprize.org/prizes/physics/1921/summary/ (accessed on 8 August 2021).
    • Solar Cell Central. Solar Electricity Costs. Available online: http://solarcellcentral.com/cost_page.html (accessed on 8 August 2021).
    • Photovoltaic System. Available online: https://en.wikipedia.org/wiki/Photovoltaic_system (accessed on 8 August 2021).
    • Esram, T.; Chapman, P.L. Comparison of photovoltaic array maximum power point tracking techniques. IEEE Trans. Energy Convers. 2007, 22, 439–449.
    • Kajihara, A.; Harakawa, A.T. Model of photovoltaic cell circuits under partial shading. In Proceedings of the 2005 IEEE International Conference on Industrial Technology, Hong Kong, China, 14–17 December 2005; pp. 866–870.
    • Trends in PV Applications 2020. Available online: https://iea-pvps.org/trends_reports/trends/ (accessed on 8 August 2021).
    • Feldman, J.; Singer, S.; Braunsten, A. Solar cell interconnections and shadow problem. Sol. Energy 1981, 26, 419–428.
    • Wang, Y.J.; Hsu, P.C. An investigation on partial shading of PV modules with different connection configurations of PV cells. Int. J. Energy 2011, 36, 3069–3078.
    • Moballegh, S.; Jiang, J. Modeling, Prediction, and Experimental Validations of Power Peaks of PV Arrays Under Partial Shading Conditions. IEEE Trans. Sustain. Energy 2014, 5, 293–300.
    • Teo, J.C.; Tan, R.H.; Mok, V.H.; Ramachandaramurthy, V.K.; Tan, C. Impact of Partial Shading on the P-V Characteristics and the Maximum Power of a Photovoltaic String. Energies 2018, 11, 1860.
    • Maki, A.; Valkealahti, S. Power Losses in Long String and Parallel-Connected Short Strings of Series-Connected Silicon-Based Photovoltaic Modules Due to Partial Shading Conditions. IEEE Trans. Energy Convers. 2012, 27, 173–183.
    • Swaleh, M.S.; Green, M.A. Effect of shunt resistance and bypass diode on the shadow tolerance of solar cell modules. Sol. Cells 1982, 5, 183.
    • Dzung, N.; Lehman, B. An Adaptive Solar Photovoltaic Array Using Model Based Reconfiguration Algorithm. IEEE Trans. Ind. Electron. 2008, 55, 2644–2654.
    • Storey, J.; Wilson, P.R.; Bagnall, D. The Optimized-String Dynamic Photovoltaic Array. IEEE Trans. Power Electron. 2014, 29, 1768–1776.
    • Velasco-Quesada, G.; Guinjoan-Gispert, F.; Pique-Lopez, R.; Roman-Lumbreras, M.; Conesa-Roca, A. Electrical PV Array Reconfiguration Strategy for Energy Extraction Improvement in Grid-Connected PV Systems. IEEE Trans. Ind. Electron. 2009, 56, 4319–4331.
    • Storey, J.P.; Wilson, P.R.; Bagnall, D. Improved Optimization Strategy for Irradiance Equalization in Dynamic Photovoltaic Arrays. IEEE Trans. Power Electron. 2013, 28, 2946–2956.
    • Shimizu, T.; Hirakata, M.; Kamezawa, T.; Watanabe, H. Generation Control Circuit for Photovoltaic Modules. IEEE Trans. Power Electron. 2001, 16, 293–300.
    • Walker, G.; Xue, J.; Sernia, P. PV string per-module maximum power point enabling converters. In Proceedings of the Australasian Universities Power Engineering Conference, AUPEC’03, Christchurch, New Zealand, 28 September–1 October 2003.
    • Kim, K.A.; Krein, P.T. Photovoltaic converter module configurations for maximum power point operation. In Proceedings of the Power and Energy Conference at Illinois (PECI), Urbana, IL, USA, 12–13 February 2010; pp. 77–82.
    • Linares, L.; Erickson, R.W.; MacAlpine, S.; Brandemuehl, M. Improved Energy Capture in Series String Photovoltaics via Smart Distributed Power Electronics. In Proceedings of the Twenty-Fourth Annual IEEE Applied Power Electronics Conference and Exposition (APEC 2009), Washington, DC, USA, 15–19 February 2009; pp. 904–910.
    • Svarc, J. Solar Panel Construction. Available online: https://www.cleanenergyreviews.info/blog/solar-panel-components-construction (accessed on 8 August 2021).
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    Solar Panel Series Parallel Calculator

    Use our solar panel series and parallel calculator to easily find which common wiring configuration maximizes the power output of your solar panels.

    Solar Panel Series Parallel Calculator

    How to Use This Calculator

    Find the technical specifications label on the back of your solar panel.

    Note: If your panel doesn’t have a label, you can usually find its technical specs in its product manual or on its online product page.

    Enter the panel’s max power voltage (denoted Vmp or Vmpp). It may also be called the optimum operating voltage.

    Enter the panel’s max power current in amps (denoted Imp or Impp). It may also be called the optimum operating current.

    In the Quantity field, enter the number of this type of solar panel you’ll be wiring together.

    If you’re using different solar panels, click Add a Panel and fill out the next panel’s specs and quantity. Repeat this process as many times as needed. You can click Remove a Panel at any time to remove the last panel added.

    Once you’ve added all your panels, click “Calculate Series vs Parallel Wiring Outputs” to compare the power outputs of common wiring configurations.

    About This Calculator

    • The wiring configurations given may not include the optimal wiring configuration for your system. (If any Smart programmers out there have some ideas on how to always find the optimal configuration, please send me a message.)
    • This calculator does not calculate your array’s maximum open circuit voltage, which is needed when sizing your charge controller. For that, check out our solar panel voltage calculator.

    How to Calculate Solar Panel Output of Series Parallel Wiring Configurations

    Here’s how to calculate the power output of your solar array, regardless of how you’re wiring your panels together.- and regardless of whether or not the panels are identical.

    Identical Solar Panels

    For identical solar panels wired in series, the voltages are summed and the current stays the same.

    For example, let’s say you have 3 identical solar panels. All have a voltage of 12 volts and a current of 8 amps. When wired in series, the 3 connected panels (often called a series string) will have a voltage of 36 volts (12V 12V 12V) and a current of 8 amps. In this example, the series string will have no losses.

    Different Solar Panels

    For mismatched solar panel wired in series, the voltages are summed and the current is equal to that of the lowest-rated panel.

    For example, let’s say you have 3 different solar panels with the following specs:

    When wired in series, the resulting series string will have a voltage of 42 volts (12V 14V 16V) and a current of 6 amps (the lowest current rating of the 3 panels).

    In this example, our series string will have some power losses because the currents of the 12V/8A panel and 14V/7A panel will get pulled down to 6 amps.

    Identical Solar Panels

    For identical panels wired in parallel, the currents are summed and the voltage stays the same.

    For example, let’s go back to the scenario of 3 identical solar panels, all with a voltage of 12 volts and a current of 8 amps. When wired in parallel, the 3 connected panels will have a voltage of 12 volts and a current of 24 amps (8A 8A 8A). In this example, our parallel string will have no losses.

    Different Solar Panels

    For mismatched solar panels wired in parallel, the currents are summed and the voltage will be equal to that of the lowest-rated panel in the string.

    For example, let’s say you have 3 different panels with the following specs:

    When wired in parallel, the resulting parallel string will have a voltage of 12 volts (the lowest voltage rating of the 3 panels) and a current of 21 amps (8A 7A 6A).

    In this example, our parallel string will have some power losses because the voltages of the 14V/7A panel and 16V/6A panel will get pulled down to 12 volts.

    Identical Solar Panels

    For identical solar panels wired in a series-parallel configuration, for each series string the voltages are summed and the current stays the same. Then, for each series string of identical length wired in parallel, the currents are added and the voltage stays the same.

    For example, let’s say you have 4 identical solar panels, all with a voltage of 12 volts and a current of 8 amps. First, you wire 2 sets of 2 panels in series to create 2 series strings of 24 volts (12V 12V) and 8 amps. Then, you wire both series strings in parallel to create a 4-panel array of 24 volts and 16 amps (8A 8A).

    When using identical solar panels, it’s important your series strings be identical length. If they aren’t, the voltages of the strings will be different.

    Generally, I recommend wiring solar panels in series first, then parallel. This limits the number of branch connectors needed and can reduce your wiring costs.

    Different Solar Panels

    For different solar panels wired in a series-parallel configuration, for each series string the voltages are summed and the current will be equal to that of the lowest-rated panel in the string. Then, when the series strings are wired together in parallel, the currents are summed and the voltage will be equal to that of the series string with the lowest voltage rating.

    For example, let’s say you have 4 different solar panels with the following specs:

    First, you wire the 12V/8A panel and 16V/6A panel in series to create a series string with a voltage of 28 volts (12V 16V) and a current of 6 amps (the lowest current rating of the 2 panels).

    Next, you wire the 14V/7A panel and 20V/5A panel in series to create a second string with a voltage of 34 volts (14V 20V) and a current of 5 amps (the lowest current rating of the 2 panels).

    Finally, you wire the 2 series strings in parallel to create a 4-panel solar array with a voltage of 28 volts (the lowest voltage rating of the 2 strings) and a current of 11 amps (6A 5A).

    Unfortunately, when dealing with mismatched solar panels in a series-parallel setup, there’s no simple rule I can give for easily finding the wiring configuration that will result in the greatest power output. Our calculator at the top of this page is a good starting point, but it may not give the optimal configuration.

    In these situations, I recommend trial and error. Calculate the output of multiple wiring configurations and go with the one that results in the greatest power output.

    Wiring Solar Panels in Series or Parallel: Which Is Best?

    Here’s a quick breakdown of when to use series or parallel wiring for your solar panels.

    Pros

    • No need to buy any extra equipment
    • Keeps current low, helping you save money on wiring costs

    Cons

    • Doesn’t work well in shade — when a single panel in a series configuration gets shaded, the power output of the entire array drops

    When to Use

    • Your solar panels will spend most of their time unshaded
    • You want to save on wire and equipment costs
    • You’re using an MPPT charge controller

    Pros

    • Works better in shade — when a panel in a parallel configuration gets shaded, the remaining panels will continue to output power as expected

    Cons

    • Requires buying branch connectors
    • May need to fuse the solar panels
    • Increases current — you may need to buy thicker, more expensive wire, and equipment with higher current ratings

    When to Use

    • Your solar panels spend most of the time in the mixed-light conditions
    • You’re using a cheaper PWM charge controller

    How to Wire Solar Panels in Series Parallel

    Here’s a quick overview of how to wire solar panels in series and parallel. For more in-depth instructions, check out our full tutorial.

    Series

    To wire solar panels in series, connect the positive cable of one to the negative cable of the other.

    Here’s a video showing you what I mean:

    If you want to connect more in series, just connect the positive cable of each additional solar panel to the negative cable of your series string. You can string together as many panels as you want like this.

    Parallel

    To wire solar panels in parallel, you need to buy the appropriate branch connectors for the number of panels you’re wiring in parallel. (You may also need to buy inline MC4 fuses and connect them to the positive cable of each solar panel.) I’ll show you how to wire 2 panels in parallel using Y branch connectors.

    To do so, connect the 2 positive solar panel cables to the compatible Y connector. Then connect the 2 negative solar panel cables to the other Y connector.

    Here’s a video showing how to do this:

    If you’re wiring more than two solar panels in parallel, pick the right branch connector for the number of panels you’ll be wiring in parallel.

    H/T to Mowgli Adventures whose calculator was a big inspiration for this one. Their blog is amazing and you should definitely check it out!

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