Solar Power System Components Demystified: What You Need To Know When Selecting The Building Blocks of Your Solar System

This article reveals the basics of the main components of a solar photovoltaic system you need to know once you have decided to go solar.

solar power components demystified

Whether you have made up your mind to buy a solar power system or build it yourself, you are to consider the following:

  • How to differentiate between the various types of solar panels, batteries, charge controllers, and inverters,
  • What affects the performance of each solar system components,
  • Which solar component is the best solution for your specific case
  • Tips on how to select the right solar building blocks for your solar power system

The article is written to help you get started by introducing you to some basic yet practical information.

How to Choose Solar panels

Solar panels are solar cells joined together.

Regardless of its size, a solar cell has a voltage of about 0.5V. Solar cells are connected in series to produce higher voltage, capable of charging a battery or directly power a DC device.

For example, 36 solar cells connected in series give a voltage of around 18V. These ‘18 volts’ can vary between 16.5 and 19 volts, depending on the cell type, and a particular manufacturer.

You would probably ask: what’s the point of generating 18V instead of the 12V needed?

Well, there are several reasons for this choice.

The primary logic is that the solar panels are designed to charge a solar battery or a solar battery bank.

What is more, the photovoltaic panels must maintain the solar battery in an optimal fully-charged state.

As you know, the voltage of a fully-charged 12V lead-acid battery can go up to 14.4V.

On the other hand, the voltage of the solar PV module must be at least 15% to 25% higher than the voltage of a battery bank to enable a sufficient charge current from the solar panels to the battery.  

The second reason is the influence of the ambient temperature on the solar panel voltage.

When the weather gets hotter, the output voltage of the solar panels decreases, and vice versa – when it gets colder, the output voltage tends to increase.

The third reason is rooted in solar power system losses.

A part of the solar-generated electricity is always lost in the other system components – wires, battery, charge controller, and inverter.

For this reason, you need a somewhat higher solar-generated power to make your appliances work.

A larger solar cell, however, obtains more sunlight and can generate higher current (or amps), although the voltage stays 0.5V.   

Although all solar panels are made of silicon, they are divided into two main types – crystalline and thin-film.

Crystalline panels are made of crystalline silicon, while thin-film ones are made of amorphous silicon.

Crystalline solar panels can be either monocrystalline or polycrystalline. They differ mostly in their appearance and less in their efficiency.

Thin-film panels are the least efficient ones, and they also have an appearance different from their crystalline counterparts.

Amorphous solar panels come with a much shorter warranty, but they are also reported to last longer.

These panels are both the least effective and the least expensive ones. Compared to crystalline panels, thin-film panels are proven to perform better in higher temperatures and when shaded.

Also, unlike mono- and polycrystalline ones, they are not fragile and can tolerate much higher mechanical loads.

In addition to silicon-based solar panels, thin-film panels encompass Cadmium Telluride (CdTe), Copper Indium Gallium Selenide (CIG/ CIGS) or Organic photovoltaic cells (OPV/ DSC/ DYSC).

Nevertheless, the most used thin-film panels nowadays are amorphous silicon-based ones.

Unfortunately, they are prone to long term degradation and complicated warranty requirements for working conditions, i.e., mounting, cleaning, excessive wear or teat, etc.

Solar panel efficiency denotes the power output produced by a panel per unit of area.

Solar panel output, however, does not depend on panel efficiency alone but is instead related also to:

  • Shading – this means any shade from a nearby obstacle, resulting in a decrease of the solar-generated power. The highest amount of electricity is produced during the brightest part of the day, which is between 9 a.m. and 4 p.m. Therefore, the most significant part of the solar-generated power can be lost exactly within this period if the solar panels get shaded.
  • The ambient temperature – the hotter the weather, the more heated a solar cell gets. The hotter the solar cell, the lower its voltage. This is an example of power losses and is one of the explanations of why panels are manufactured to produce voltage higher than the battery voltage.
  • Orientation and tilt. When the sunbeams do not hit the solar panel surface perpendicularly, a part of the sunlight that can be possibly converted into power is lost as a result of reflection. Indeed, solar panels are commonly mounted on the roof, which means that there is no way to track the sun’s position in the sky all the time. However, an optimal tilt exists for every location on the earth, and every season. To find the optimal tilt angle is vital, especially in winter, when there is less sunlight, and you need to maximize the power output of your PV system.
  • Improper wiring – selecting the components for a PV system goes hand in hand with properly sized wires by applying the required gauge and correctly implemented connections. A wire larger than needed is hard to bend around the corners and costs more. A smaller wire results in voltage drops and overheating, which is dangerous for your system.
  • The electrical load – this means at what voltage and current the panel is operating so that it produces the maximum solar-generated power. This specific point, which is a part of the I-V curve, is called ‘peak power’ (PP) point. If you use an MPPT charge controller, it will guarantee that your solar panels are operating at the peak power. This means 30% more solar power produced and, hence, 30% less time to charge your battery than other types of charge controllers.

One of the frequently asked questions is whether to choose higher wattage or lower wattage panels.

In other words, this also means “Are larger solar panels better?”

The answer is, “It depends on the solar power application.”

For example, if you plan to install solar on your RV or boat, larger panels are not recommended.

Yes, you get tempted by avoiding connected a couple of smaller panels in series or parallel but … above all, there might not be enough space on your roof to position one larger panel.

Second, larger panels are more dangerous if you drive at high speed since they put more strain on the mounts and make them more vulnerable to shocks and vibrations.

Third, the risk of shade is higher if you have one large panel on your roof compared to a couple of smaller ones.

Last but not least, larger in size and higher wattage panels mean voltage much higher than 16-19V, which is not so convenient for the 12V battery voltage typical for mobile PV systems.

In such a case, no matter how much total solar-generated power you actually need, you should buy an MPPT charge regulator to bring down the voltage down to 12V.

Thus, you can benefit from the higher power efficiency of the MPPT controller.

Otherwise, you may incur significant losses in the solar-generated power.

Indeed, larger and higher wattage solar panels are easier to find.

They are better suited, however, for residential solar systems. If your home solar PV system is grid-tied, it’s not a problem for the inverter to handle a higher voltage.

If you are living somewhere off-the-grid, you probably have an MPPT controller to maximize the solar-generated electricity and be able to power as more appliances as possible.

Larger solar panels look much more aesthetically.

To cut a long story short, they also allow you to expand your solar system much easier.

Here are some commonly valid solar panel tips:

  • During the initial survey of your site, you are supposed to identify all the nearby objects that can throw shade onto your solar panel area. This, however, is not the whole story. You should also take care of ‘maintaining’ this clearness by keeping track on any tree branches, bushes, or other objects that might appear, often ‘out of the blue.’ Indeed, here also comes the need for regularly cleaning the solar panels.   
  • Asking the question “How many panels do I need to cover my needs?” goes hand in hand with “Can I reduce my needs to need less power”?
  • The more panels you have on your roof, the easier they can get shaded. Also, the more panels on your roof, the more surface you need to clean. Last but not least, higher power demand means a bulkier and costlier battery, which, if flooded lead-acid one, needs more commitment to maintaining.
  • Connect panels with matching voltage ratings only. Both in series and parallel connection, plugging a panel of a lower power rating drags down the solar-generated power of the array. Also, if you have an MPPT charge controller, it will have problems to track the maximum power point correctly.
  • Bypass diodes are only intended to cope with occasional shading occurring with solar panels connected in series. If you are to join panels in parallel, you don’t need bypass diodes. Often, bypass diodes are integrated into the solar panel’s junction box.

You can learn more about the all solar components, their efficient usage and the best way of combing and interconnecting them in our “The New Simple And Practical Solar Component Guide” available in ebook, paperback, and unabridged audiobook editions.

You can discover more about this simple, practice and money-saving guide and how to get its different editions on different online platforms worldwide by going to our web page by Clicking Here.

How to Select Solar Batteries

In solar power systems, solar batteries are used to store solar-generated electricity.

Batteries used in solar power systems are deep-cycle ones. Under ‘deep-cycle,’ we mean a battery discharge (down to 50% for lead-acid batteries and 80% for lithium ones) followed by a full recharge, which in PV systems is provided typically by the solar panels.

Each deep-cycle battery has a limited number of deep-cycles, that is, regular discharges and recharges.

Car starting (also known as ‘cranking’) batteries are not suitable for use in solar power systems since they are not designed to be regularly discharged and recharged (the ‘deep-cycle’ regime).

Instead, their greatest strength is providing a high current within a very short period, needed to start an auto engine.

With its electrodes being exposed to irreversible sulfation and corrosion as a result of every day charging and discharging, a casual car battery is reported to last as low as up to 30 charge/discharge cycles when intended to replace a typical deep-cycle battery in a PV system.

If you have a caravan, camper, RV, or boat with a solar power system installed, you have two batteries – a cranking one and a leisure one.

The cranking battery takes care of starting the engine of your car or camper, while the leisure battery power all the devices you use in your motorhome.

The leisure battery should be a deep-cycle one, although the solar panels are not the only option of recharging.

Apart from the solar panels, your leisure battery can also be recharged by an external (diesel) generator, a shore power source (‘hookup’) or an extra alternator installed in your vehicle.

A lithium battery lasts between 2,500 and 500 cycles, while the best AGM batteries offer you up to 1,000 cycles.

Anyway, a lithium battery costs about three times more than an AGM one.

All deep-cycle lead-acid batteries, whether flooded or sealed (a gel or AGM), are not recommended to be discharged more than 50% of their rated capacity.

A lithium battery tolerates much deeper discharges – to as low as 80%.

Therefore, due to the different usable capacity, it is not entirely correct to compare the rated capacity of a lead-acid battery and a lithium battery.

While a lead-acid battery is charged, the battery voltage is changing with the state of charge.

The higher the state of charge, the higher the voltage between the battery terminals.

In lithium batteries, the voltage is not dependent on the state of charge, so you cannot assess the state of charge of a lithium battery by measuring its voltage.

Instead, they have safe operational areas in terms of voltage, temperature, charge, and discharge.

For this reason, every lithium battery must be provided with a Battery Management System (BMS; some lithium batteries it integrated) to take care of battery charging and discharging.

Although discharging a lithium battery down to 0% can damage it, one of the advantages of lithium batteries is that a battery does not need to get a full charge every day.

Another advantage is that lithium batteries get charged to their full capacity much faster than their lead-acid counterparts.

Also, due to the utterly different chemistry, the electrodes of lithium batteries are not prone to sulfation decreasing their lifespan, as is the case with lead electrodes.

Furthermore, lithium batteries are practically maintenance-free as the BMS ‘takes care’ of the maintenance.

Flooded lead-acid batteries are up to 85% efficient. AGM and gel batteries have somewhat higher efficiency but not above 92-93%.

Lithium batteries offer you an efficiency of nearly 100%, which means that with a lithium battery, you have higher solar-generated power than with a lead-acid one.

On the one hand, this means that you have more solar power squeezed during the sunlight hours.

On the other hand, lower battery losses allow you to tolerate higher losses in other system components – for example, the charge controller or the cabling.

Although both lead-acid and lithium batteries tend to reduce their available capacity in low temperatures, lithium batteries perform better when exposed to cold (although not freezing) temperatures. The same is valid for hot weather.

Therefore, due to their better efficiency, lithium batteries are preferred in extreme weather conditions.

For a properly maintained and operated flooded lead-acid battery, a typical lifespan of 5 years can be assumed, although it can last more (up to 7 or even 10 years).

For a sealed lead-acid battery, 3-4 years are typical lifespan, although 5 years are also possible. In comparison, lithium batteries are known to last more than 10 years.

Last but not least, lithium batteries are much easier both to store and transport than lead-acid ones.

Lithium batteries are smaller, lighter, and do not release flammable hydrogen gas during charging. For this reason, they are the best long-term investment for mobile solar power systems.

AGM batteries get their full charge much faster than their flooded counterparts.

On the one hand, this means less time to recharge the battery. On the other hand, it means that you might not need an MPPT controller to speed up the time for recharge by squeezing those 30% more power from the solar panels!

A great benefit of AGM batteries is that they do not vent gas during charging and that their terminals are not exposed to corrosion.

Also, you don’t need to add distilled water regularly, which can save you both time and money for maintenance.

Here are the primary issues that can shorten the lifespan of your lead-acid battery:

  • Regular overcharging, where the electrolyte starts boiling and evaporating. On the one hand, this imposes adding extra distilled water to the electrolyte. On the other hand, the heat released shortens the life of the electrodes.
  • Regular over-discharging (down to more than 50%) – it shortens both the battery capacity and lifespan.
  • Keeping the battery not fully charged. Even if you don’t draw power regularly, you should keep the battery fully charged. Otherwise, their available capacity reduces, as the electrodes start (although slowly) to sulfate.
  • Not adding distilled water regularly. Also, adding anything else other than distilled water can additionally expose the electrodes to corrosion due to the chemical reactions caused by the various impurities and minerals in different types of water.

AGM batteries are less susceptible to self-discharge than flooded lead-acid batteries, so they are good to use as leisure batteries for occasional camping.

If you have an AGM battery, we advise you not to skimp on a high-quality charge controller.

Thus, your battery will have a longer lifespan. As with sealed lead-acid batteries, you cannot and don’t need to add water regularly; the biggest challenge is to cope with overcharging and over-discharging to avoid plate sulfation.

A suitable and adequately configured charge controller can take care of both.

A battery of higher capacity than you actually need is costlier, bulkier, and heavier. Furthermore, you need more solar panels to recharge it.

Also, you should not forget that solar panels practically do not generate electricity (or at least, you cannot benefit from it, which is the same!) after the battery gets fully charged.

Thus, a battery of lower capacity means you not only have a lower daily electricity usage target but also that you do not benefit from the peak sun hours at your location.

Gel batteries are noted for their robustness to very low temperatures. Another advantage is tolerance to deeper discharges.

However, they are not tolerant to overcharges, so we recommend you AGM batteries to gel ones.

Marine batteries are not typical deep-cycle batteries, but somewhat hybrid ones, as they are intended to use both as starting and solar batteries.

We don’t recommend marine batteries for your mobile solar power system. Instead, try to find true deep-cycle batteries.

What kind of battery to choose for your off-grid system depends on HOW you would use the solar battery:

  • For a remote home, where you live all the year-round, a flooded lead-acid battery would give you the best value for the price. However, if you can afford the cost and if you both have great daily electricity use and want your battery to last more, you can choose a lithium one.
  • For an off-grid cabin or villa, where you go mostly in summer or at weekends, a sealed lead-acid battery is an optimal solution. A flooded lead-acid battery needs maintenance you obviously will not be able to provide being there just occasionally. Exactly for the same reason, a lithium battery would be a too costly option.
  • For a grid-tied system with power backup – if outages happen often, a flooded lead-acid battery would be the optimal solution. In case of rare power outages, however, you’d better choose a maintenance-free battery (either sealed lead-acid or lithium) than getting engaged in constant maintenance activities to benefit from this battery just once in a blue moon!
  • For your RV or boat, a sealed lead-acid battery gives the best value for the price but, again, a lithium battery lasts longer and performs better if you can afford it.

Finally, to enable always your battery getting a full charge, you should minimize the voltage drops between the charge regulator and the battery. You can do this either by reducing the cable length or by using a larger cable gauge.

The latter will not only help you improve the performance of your system but also to eliminate any fire hazards.

When selecting the proper battery, one of the things you should be careful is the discharge rate. Some manufacturers might try to deceive you by stating a too low discharge rate that is unlikely to achieve in practice with all the loads you intend to power.

The truth is that the higher the load, the faster the battery gets discharged.

The reason is called ‘Peukert effect,’ which decreases the battery’s efficiency with increasing the number of loads connected.

For example, you might encounter a battery of 150 Ah at stated 1 amp rate of discharge, which means that if you have a load of 1 amp, your battery will last 150 hours.

In fact, your consumption is always higher – it can be 4, 5, or 6 amps. In such a case, this battery is going to be drained disproportionately faster than 150 hours.

If we assume the standard 20-hour rate of discharge and discharging current of around 5 amps (five times higher than 1 amp), it might turn out that this battery has a capacity of 120 Ah, rather than 150 Ah.

So, it seems that the boosted value of 150 hours serves for nothing provided that you might never intend to run a 1-amp load for 150 hours! 

You can learn more about the all solar components, their efficient usage and the best way of combing and interconnecting them in our “The New Simple And Practical Solar Component Guide” available in ebook, paperback, and unabridged audiobook editions.

You can discover more about this simple, practice and money-saving guide and how to get its different editions on different online platforms worldwide by going to our web page by Clicking Here.

How to Select Solar Charge controllers

A solar charge controller, also known as ‘charge regulator,’ is a device protecting the battery from overcharging and over-discharging. It is used in battery-based solar power systems and is placed between the solar panels and the battery.

Since the solar charge controller supervises the whole process of charging the battery by the solar array and manages the time within which the battery gets a full charge, it prolongs the battery lifespan.

Also, the charge controller acts as a blocking diode by stopping the reverse current from the battery to the solar panels at night, thus preventing battery discharge.

Even if you decide to buy a good quality charge controller, its cost is not likely to contribute significantly to the overall cost of the solar system.

If you, however, want your battery to last at least 5 years, a good quality charge controller is a must.

There are two main types of charge controllers – PWM (Pulse Width Modulation) and MPPT (Maximum Power Point Tracking).

MPPT regulators are more sophisticated and more efficient but also more expensive (about 2.5 times more) than PWM ones.

If you use a PWM solar charge controller, the output voltage of the solar panel array should be equal to (or slightly higher than) the battery voltage.

Otherwise, any excess voltage is lost as heat and cannot contribute to battery charging.

Above all, we recommend you to compare the total open-circuit voltage of the solar array (Voc) to the maximum input voltage of the controller.

Also, regardless of whether you have a PWM or an MPPT regulator, you should compare the total maximum power point current (Imp) of the solar array to the maximum input current of the controller.

Should the total Imp exceed the rated input current of the controller, you might consider using multiple charge controllers connected in parallel to the battery bank.

With an MPPT solar charge controller, the output voltage of the solar panels need not match the battery voltage, as the MPPT controller successfully transfers the excess voltage into higher charging current and no power is lost as heat.

An MPPT solar charge controller gets 30% more power from the solar panels to transform it into battery charging current.

Therefore, installing an MPPT controller on the roof of your house or RV is practically the same as installing more solar panels.

Thus, if you have limited roof space, and your daily electricity use is relatively high, it’s natural to select an MPPT controller.

MPPT controllers cope better in case of a significant difference between the solar array voltage and the battery voltage.

Otherwise, the less expensive PWM controller will do.

Furthermore, MPPT controllers are particularly advantageous if:

  • Your battery gets deeply discharged every day (but not above 50%, of course!). In such a case, an MPPT controller shows its most significant benefit of increasing the battery charging current and reducing the time for reaching the full state of charge. If you don’t discharge so deeply your batteries daily, an MPPT controller would be of less use.
  • In cold climates, when the maximum power peak voltage of the solar panels is higher. As we pointed above, the greater the difference between the panel voltage and the battery voltage, the better the controller performance.

Therefore, you don’t need an MPPT charge regulator if:

  • You live in a hotter place,
  • You don’t discharge deeply your battery every day,
  • Your panels are connected in parallel rather than in series, and their nominal voltage coincides or is slightly higher but very similar to the solar battery nominal voltage, or
  • You have installed a sufficient number of solar panels and do not need to maximize their performance.

Indeed, if you have 24V or 48V solar panels connected to a 12V battery bank, you cannot do without an MPPT controller.

However, before purchasing the components, you have to check in both the panels and controller spec sheets whether the maximum voltages are within the permissible limits.

The Low Voltage Disconnect (LVD) feature of the charge controllers prevents the battery from over-discharging and therefore, from reducing the battery capacity and lifespan.

LVD in charge controllers disconnects the DC loads from the battery when the battery voltage (in case of lead-acid batteries) falls below a particular value – 11V for 12V batteries and 22V for 24V batteries.

Most inverters, as power providers to AC loads, also have a built-in LVD feature, so that they can be connected directly to the battery.

Otherwise, they should be connected to the battery via the charge controller.

If you have DC loads and want to buy a charge regulator with built-in LVD, you must compare and check the LVD-amps to the amps being drawn from the battery by all the DC devices operating at the same time.

Temperature sensing is another essential feature of charge controllers.

As we know, temperature strongly influences the battery charge and discharge.

A cold battery is easier to discharge and harder to recharge, which means that it needs a higher voltage to get recharged.

A warm battery is harder to discharge and easier to recharge; therefore, it needs a lower charging voltage.

A charge controller with a built-in temperature sensing feature will assess the ambient temperature and will adjust the battery charging current according to it.

Without temperature sensing, a battery will be highly vulnerable to seasonal variations in temperature and is likely to get damaged after just one year of use.

It is vital to make sure to configure your charge controller correctly for the battery you have. Otherwise, your battery can get ruined quickly.

You can learn more about the all solar components, their efficient usage and the best way of combing and interconnecting them in our “The New Simple And Practical Solar Component Guide” available in ebook, paperback, and unabridged audiobook editions.

You can discover more about this simple, practice and money-saving guide and how to get its different editions on different online platforms worldwide by going to our web page by Clicking Here.

How to Select Solar Inverters

Once you decide to solar-power AC appliances, you need a solar inverter.

Although DC-versions of some widely used devices are gaining popularity, the truth is that a lot of the appliances at your home or RV operate on AC and we can hardly do without some of them!

For a grid-tied system (which is a battery-less one), the solar inverter takes the DC solar-generated electricity directly from the solar panels and converts it into AC (120V or 240V).

For a battery-based PV system (either off-grid or grid-tied with power backup), the inverter draws DC current from the battery bank.

Despite the apparently identical task of converting DC to AC, the solar power inverters in battery-less and battery-based systems are entirely different devices and cannot be used interchangeably!

One of the primary specs of any solar power inverter is its wattage, that is, the total wattage of all the AC devices plugged in at a given moment.

Inverter wattages vary within a considerable range (between 500 and 5,000 W). Some of AC devices, however, produce ‘surges’ when started.

These surges are peaks in their consumption, which the inverter certainly must be able to handle.

Typical surging devices are refrigerators.

If a refrigerator has a wattage of 1,000W, peaks of 3,000W are not unlikely to occur at startup, within the first couple of seconds.

For this reason, considering all the surging appliances in your household or RV, you should select an inverter with a wattage higher than the total wattage of the DC devices you are powering.

There are three types of off-grid inverters on the market – Square Wave, Modified Sine-Wave, and Pure Sine-Wave.

Although solar Square-wave inverters were the first to appear on the market, nowadays they are instead a poor choice for your home or RV solar due to the bad quality of the AC signal they produce.

Modified Sine-Wave inverter can power lots of devices, but they provide AC signal with inferior quality than Pure Sine-Wave inverters.

Some devices with moving parts do not work well with Modified Sine-Wave inverters, and their lifespan might even get reduced.

Also, Modified Sine-Wave inverter can bring interference in the operation of some radio-, TV- and communication devices (by making them buzzing).

For these reasons, Pure Sine-Wave (also known as ‘True Sine-Wave’) inverters are recommended as the best option for any AC devices.

Some solar inverters have additional functionalities which make them suitable for RV solar power systems.

For example, an inverter can act as a battery charger, when connected to shore power.

Also, there are ‘hybrid’ inverters capable of synchronizing their power output with a shore power source.

Thus, you can run larger loads without being in fear that these are going to drain your battery in a short time.

Here are some tips before proceeding to select an inverter for your home or RV solar panel system:

  • Make a list of the devices you intend to run simultaneously and add their powers. What you eventually get is the inverter ‘continuous rating.’
  • While listing appliances and adding powers, don’t forget the ‘phantom loads’ – all the tiny devices such as alarms, detectors and plugged-in chargers (for phones, laptops, GPS, etc.) that seem to be doing nothing but are drawing power from the battery! It’s wise to avoid such appliances and, when possible, to switch them off!
  • Consider the surging ones among them and add their rated powers separately. Eventually, what you get as a result is the continuous rated power that should be multiplied by 3 to get the additional wattage you need within a couple of seconds. This wattage is known as ‘surge rating.’ Mind that if an inverter is not capable of handling the surge power of a device, it is going to shut down rather than start that device!
  • Consider the fact that any inverter has losses which affect the solar-generated electricity. A typical value of inverter efficiency is 90%, i.e., power losses of 10%, but it can also be higher or lower. By doing some simple math, you can see how lower or higher inverter efficiency changes your solar power yield.

The bad news is that the inverter efficiency is not constant but depends heavily on how the inverter is being loaded.

So, the efficiency of an inverter varies on the total load, and upon just a few small electrical loads plugged in, the efficiency is much lower than 90%.

For this reason, what is stated by inverter manufacturers is the ‘peak efficiency’ or ‘maximum efficiency.’

It is, therefore, the maximum possible value at a full load. If the total power of the devices being plugged in is less than 200W, the real efficiency is lower.

Often manufacturers depict an ‘efficiency curve’ rather than specifying a single value.

Some manufacturers, however, deliberately cut off a part of the information by showing the efficiency curve starting from 100W or 200W, rather than from zero.

Thus, they hide from you how much the efficiency of an inverter running small loads differs from its peak efficiency! 

  • In case of a home solar power system and too higher wattage exceeding the inverter’s rating, you can stack two identical inverters by wiring them in series and increase the maximum wattage of the loads to handle.
  • If you have an RV system, consider buying an inverter with a built-in battery charger.
  • Consider the idle power of the inverter. This is the power the inverter is drawing in idle state, that is, upon no AC devices plugged in. The idle power of the inverter can vary between 10W and 50W. Indeed, to avoid idle mode power consumption, you can buy an inverter with an automatic on/off feature. It, however, can bring another downside for some appliances which operate with pause cycles, such as washing machine. You know that a motor of a washing machine makes some pauses when running. If you only have your washing machine plugged in, during such a pause, the inverter might sense there is no device drawing power and might shut down, which is undesirable!
  • Consider the inverter size and weight. Typically, more powerful inverters are bulkier, weight more, and cost more. If your space is limited, think of eliminating some of the AC appliances and, if possible, find the relevant DC-substitutes.

The article aimed to present you the basics of solar power system components.

For more detailed, yet practical and applicable info, we recommend you the book ‘The New Simple And Practical Solar Component Guidewhich is your guide if you are planning to buy a PV system or implement by yourself.

You can discover more about this simple, practice and money-saving guide and how to get its different editions on different online platforms worldwide by going to our web page by Clicking Here.

Here are some of the issues discussed in the ebook, paperback, and unabridged audiobook edition:

  • How to compare solar panels produced by different manufacturers
  • What you should know on wiring solar panels and mixing different solar panels
  • Essential info on all main types of batteries used in residential and mobile solar power systems
  • How to select the right type of battery for the system you are about to buy or build
  • The primary issues related to battery maintenance and safety
  • Connecting batteries and battery sizing – the basics, what to do and what to avoid
  • How to select the right type of charge controller
  • How to squeeze more power if you have wired non-identical panels in a solar array
  • The basics of charge controller sizing
  • Inverters for grid-tied and off-grid systems – modifications, requirements, and specifications
  • How to select and size an inverter based on your daily needs
  • Info on the other equipment vital for a solar power system to operate
  • A comprehensive chapter dedicated to the specifics of the components in mobile PV systems.

You can discover more about this simple, practice and money-saving guide and how to get its different editions on different online platforms worldwide by going to our web page by clicking on Link Below:

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Lacho Pop, MSE, holds a Master's Degree in Electronics and Automatics. He has more than 15 years of experience in the design and implementation of various sophisticated electronic, solar power, and telecommunication systems.  He authored and co-authored several practical solar books in the field of solar power and solar photovoltaics. All the books were well-received by the public. You can discover more about his bestselling solar books on Amazon on his profile page here: Lacho Pop, MSE Profile