How Does Solar Energy Work?

As an Amazon Associate, this site earns commissions from qualifying purchases. For more details, click here.

Solar power use increases year after year in the US and around the world. From commercial establishments, industries, to homes, to individuals with portable solar chargers, there is no denying its popularity. And with the world in need of an alternative energy source – fossil fuel is finite – solar is the most practical alternative. In this guide, we’ll explain everything you need to know about solar energy.

Solar power is energy from the sun. Through a chemical phenomenon known as the photovaltaic effect, the sun’s energy can be turned into electrical current. The power is used for smartphones, refrigerators, lights, laptops, TVs and other electronic devices.

How Does Solar Energy Work?

A solar power system works via the photovoltaic effect. It is like this: when the sun’s rays hit the solar panels, the panels generate current. This current is transformed into electricity that can be used in laptops, phones, TVs and other electronic devices and appliances. To convert the sun’s energy into electricity, a solar power system or solar power station is required.

The following diagram shows how a typical solar power system is configured.

To obtain the sun’s energy, you must have a solar power system. These systems come in different forms, shapes and sizes, but they include the following. The following are often found in home and RV solar power systems. Depending on the configuration and requirements, an inverter may not be included in the set up.

Solar Panel

The panel is the most well known part of a solar station. The surface consists of individual cells set under glass. Each cell has a conductive surface made of silicon. When the sun’s rays strikes the cells, a chemical reaction takes place, producing electric current. A solar array consists of two or more solar panels joined in a series or parallel configuration, which is the usual setup for homes.

Solar Panel Sizes: solar panels are available in two standard sizes: 72 cells (39 x 77 inches) and 60 cells (39 x 65 inches). These two are the standard for residential solar power systems, but other portable panels for RVs and power solar stations are available. Large, 96 cell grids are slowly becoming common as well.

60 and 72 cell solar panels are rigid, but flexible thin film panels can be installed as well. These are portable solar panels designed for backpackers, RVs and general mobile use. They’re not as powerful as rigid panels but they are lighter and can be used anywhere.

Cell Composition: The cells are made of monocrystalline or polycrystalline. Mono cells are comprised of a solitary silicon while multiple silicon are used in poly cells. Mono cells are more efficient and also cost a bit more. However there are a lot of factors that affect the efficiency of solar panels besides the cell makeup (i.e. weather, orientation of the panel, built etc.).

Solar panel efficiency rating determines how much of the sun’s energy is converted into electricity. The average efficiency rating of solar panels is 17%-24%. That sounds low, but it’s more than enough for homes. If you need higher efficiency you can always build a solar array. Solar arrays are common in homes, but solitary solar panels are preferred for RVs due to limited roof space.

Inverter

The inverter turns solar energy into AC electricity appliances and electronic devices can use. Solar power is DC, but majority of consumer electronics is AC, so an inverter is required. It is important that your inverter is of the right size to run whatever appliances you want to use. The most common types of inverters are micro and string inverters.

String Inverter: a string inverter consists of solar panels joined together, with the final panel connected to the inverter’s string input. All the panels are on a single circuit so every panel performs at a similar level. The drawback is if one panel’s output goes down, everything is affected. If a tree branch blocks one panel, output drops and the rest of the arrays are affected.

String inverters are affordable and widely available. Due to the limitations you should only use it in clear, unobstructed areas. You may also install a power optimizer to improve performance. A power optimizer enables the unit to manage the panels’ output independent of each other. If a panel’s output goes down, the rest won’t be affected.

Micro Inverter: in a micro inverter system, each panel has its own inverter. They are independent and do not affect the other panels. You can remove or install a new panel and the performance of existing panels will be the same as before. Micro inverters eliminate the need for a power optimizer. It’s also ideal for scaling solar power systems as you can install additional panels without worrying about the effect on your current setup.

A solar panel and inverter are all you’ll need if your home is connected to power lines. To live off the grid however, you need two more components, a battery and charge controller.

Battery

The battery serves as the solar power system’s storage. You don’t need a battery if you’re on a grid tied system as the grid serves as a storage unit. Anytime you need extra power, you can draw from the grid and feed it into your system.

Because you’re connected to the power grid, you’re affected no matter what. So if there’s an outage, you won’t be spared. In the unfortunate event of a days long blackout, a battery is worth considering. It is an extra cost, but you have peace of mind in case of a blackout.

Power grids automatically shut down if there’s a problem to protect repairmen, so you won’t have access to solar power unless you have a battery. You can also store extra solar power in the battery and sell it to the grid.

If you’re off the grid, a battery is a must. Without a battery there’s no way to store the energy your solar panel generates. Whether you’re living in a remote location, in an RV or want to be free from the power grid, a battery is indispensable. Because these don’t come cheap, you have to make the batteries last as long as possible.

Types of Solar Batteries

You have three choices. Technically two since one is a variant of the other.

  • Lithium ion
  • Flooded lead acid (FLAs)
  • Sealed lead acid (SLAs)

Flooded lead acid batteries are the oldest and cheapest. FLA is cheap but requires regular maintenance. You must regularly refill it with water (every 2 to 4 weeks), perform an equalization charge every 90 days and recharge before the battery drops to the halfway mark.

Sealed lead acid batteries are similar to FLAs, except it is sealed. This not only prevents gassing but also eliminates the need for monthly maintenance. SLAs are also more expensive than FLAs.

Lithium ion is the most efficient solar battery available. The lifespan is longer, discharge cycles are deeper and it needs zero maintenance. Charging time is longer and warranties are longer too. Lithium ion is more expensive than SLA or FLA, but it lasts three times longer or more.

Racking

Racking refers to the mechanism used to mount your solar power system. This applies both to home installations and solar panels for campers and RVs. Portable solar generators do not require mounting equipment.

Charge Controller

A charge controller manages the battery as it stores current from the solar panel. Grid tied systems do not require a charge controller unless a battery was installed. All off grid solar power stations require a charge controller to ensure optimum battery performance.

A solar power system also includes wires, cables and connectors to link the parts. A monitoring system can be installed to keep track of performance. Portable solar chargers include built in flashlights and USB / 12 ports and AC/DC outlets.

Do I Need a Solar Tracker?

These are mounts designed to track the sun’s movement to optimize your solar panel’s production. There are good solar trackers available and there are claims it can boost production by up to 30%. So why aren’t they considered standard equipment?

Because the increase isn’t worth the cost. Solar trackers cost more than solar panels. It is cheaper to buy another solar panel than a tracker and you’ll double the output. Why settle for a 20% to 30% increase when you can get a 90% to 100% boost at a lower cost?

What is the Difference between Off Grid and Grid Tied Systems?

Before you install a solar power system, decide if you want a grid tied or off grid system.

Grid Tied System

Here your solar power system is connected to the utility power grid. Solar panels draw energy from the sun and stores it in the grid. When you need solar power, you take it from the grid.

ProsCons
Cheaper than off grid systems.If the power grid goes down, you don’t have access to solar power
You don’t have to buy a battery because the utility grid serves as your storage unit.You are reliant on the grid
Most states are willing to buy extra excess solar energy you generate, allowing for faster recouping of investment. Solar energy also increases a property’s value.You don’t save as much compared to off grid systms.

A grid tied system is for you if:

  • You want to recover your investment quickly
  • You don’t want to spend extra money on batteries
  • You don’t mind being connected to the grid
  • You want to profit by selling extra solar energy to the grid

Off Grid System

Here your solar power system runs independently from any power grid. You have your own power plant. You can set up an off grid system for your house or RV.

ProsCons
Energy independence: you won’t be affected if the utility grid blacks out.More expensive than grid tied systems as you have to buy a battery.
You pay zero electricity bills.Takes longer to recover your investment.
You can go anywhere in your RV and still have access to power.Requires some knowledge of solar power to set up

An off grid system is for you if

  • You want to be energy independent
  • You don’t want to pay power bills anymore
  • You want power available even if the power grid goes down
  • You live in an RV and want to be energy independent

What are the Different Types of Solar Power?

Today’s solar power systems come in various forms, sizes and specifications. Here’s a quick rundown of what’s available.

Home Solar Power Systems: they are solar power systems designed for houses. These are usually 60 or 72 cells set in an array. These systems range from 1,000W to over 15,000W and can power an entire house including appliances.

Solar Generators: these generators serve a similar function as their diesel counterpart except the unit uses solar power. Sizes range from portable solar generators for camping to thousand watt systems for home emergency backup power.

RV Solar Power Systems: as the name suggests, these solar power systems are for campers, trailers and RVs. They’re smaller than home solar power systems but still provide plenty of power. Sizes range from 100W upwards. RV solar power systems require batteries. Solar panel arrays can be installed for more power, though space is limited on RV roofs.

Portable Solar Chargers: these are light, portable solar power banks designed for backpackers, hikers and on the go charging. The most common types are:

  • Solar phone chargers: consists of a solar panel and a USB port. You charge mobile devices directly on the panel.
  • Solar battery packs: devices are charged by the battery. The battery is recharged by solar panels (may or may not be included).

Solar Power Kits: with DIY kits you can build a portable solar power system. The kit includes an inverter, solar panels and all the required cables. Batteries are often sold separately. Sizes and specs vary though most are in the hundred watt level range. Of course you can always connect it to other solar panels.

What Size Solar Panel Do I Need?

It depends on how much energy / kilowatt hours you consume. To find out your energy requirements, look at your utility bill. You need daily watt hours used, so if it is not stated, divide the monthly kilowatt hours by 30. Divide the result by 24 and you have your hourly usage in kilowatt hours.

If your monthly consumption is 900 kilowatts, that’s 30kW a day or 1.25kW every hour. Multiply your hourly consumption by 1000 to get the watts. Finally, multiply the wattage by the number of sunlight hours your location receives. In the US it’s usually 6 hours. In our example that is 6250 watts. Look for a solar panel that can produce that amount plus 25% at least.

Why another 25%? Because solar power systems (the panels, batteries and inverter) lose some power during the energy absorption process. This is normal so you need to make allowance for it.

Solar Power System Installation

There are pros and cons to installing a solar power system yourself and hiring a professional installer to do it for you. Let us take a look at each one in detail.

Cost of Hiring a Solar Power Installer

Fees of professional solar installers depend on your location and the size of your solar power system. Competition keeps prices down, so states with more installers have lower rates. The average cost of a solar installer is 75 cents to $1.25 per watt. California produces 37% of the total solar power in the US so you’ll pay less there.

Using the 75 cents – $1.25 per watt as our example, a 5kW installation will cost $3,500 to $6,200. This is only the labor fee and does not include the equipment cost. Smaller systems will cost way less.

DIY Solar Power Installation

You can save thousands of dollars in installation fees by doing it yourself. RV solar panels are easy enough to install. Basically you just hook up a cable to a port and fasten some screws. The difficult part is hoisting the solar panel to your RV’s roof, so this is a job for two people.

DIY solar installation is doable on RVs, but it is more challenging for a house. If you’re going to install an array of solar panels, inverters and test several appliances, you’ll probably better off hiring a professional installer.

Bottom line: if you’re handy with cables and tools you can install a solar power system. If not, better bite the bullet and let the professional do it. Do not attempt to install a solar power system in your home if you don’t have the know how. You risk injuring yourself getting on the roof or damaging the components, adding to the cost instead of reducing it.

Roof Mounted vs. Ground Mounted Solar Panels

Roof mount installation is preferred by most because it’s cheaper. Mounting hardware is not required and there’s no need to build a support structure. The drawback is you have to put the solar panel on the roof, not an easy task. And if the solar panel or arrays need repair you have to get up there.

A ground mount installation requires a metal substructure to support the solar panel or arrays. It’s more expensive, though the benefit is it’s on the ground. If a problem occurs you can easily get to it and do the repair.

A pole mount can be installed on a ground mounted installation. This pole keeps the system above ground and prevents the panel from being buried under snow. It also prevents ground obstructions from getting in the way., Pole mounts are essential if you opt for ground installation in a snow prone location.

Roof Mounted Solar Panel

ProsCons
Lower labor costDifficult to repair
Easier to get permitsHard to access
Doesn’t take up valuable spaceExposure to high temperatures could reduce output
Requires fewer materialsReplacing is difficult
Suitable for those with small propertiesConstrained to roof size

Ground Mounted Solar Panel

ProsCons
Easy to cleanMore expensive installation
Not exposed to high temperaturesNeeds more components
Troubleshooting is simpleNot visually pleasing to some
No hassle repairSecuring permits might be more costly
Easy accessOccupies considerable land

Are you still having trouble deciding which installation to go with? Here are the biggest factors you need to consider. You should answer them before proceeding.

How much are you willing to spend?

  • How much real estate do you have in your home or RV?
  • Is your soil suitable for ground mounted solar panels?
  • How old is your roof?
  • Does your homeowners association allow roof mounted solar panels?
  • Do you plan to expand your solar panel system?
  • How hot does it get in your location?

How Long Does a Solar Power System Last?

Solar power systems last for a long time. 60 and 72 cell solar panels usually have 25 year warranties. Most last way longer than that. As long as the solar panels are used properly and well maintained. they should be good for years even after the warranty expires. Portable solar generators and solar chargers have shorter warranties, but they’re still good for a few years.

Inverters last for 10 to 20 years. Just like solar panels, an inverter should still be usable after the warranty expires, but expect to replace it at least once during the panel’s lifespan. Lithium ion batteries are good for at least 12-15 years and lead acid batteries about 7 years. The batteries are the most likely components you’ll need to replace in the system.

Solar Power System Maintenance

Solar power systems need very little maintenance. While the system has different components, they should last a long time.

Solar panels: about the only maintenance required is removing dirt and debris that could hinder energy production. Most of the time a good rain will remove the dirt. If not, wipe the surface gently with a brush. You only need to do this a couple times a year. A bit more cleanup will be required if it snows, but that’s all.

Batteries: lithium ion batteries don’t need maintenance, same with sealed lead acid batteries. Flooded lead acid batteries require water refilling every few weeks. Solar batteries should be placed in clean locations to prevent dust buildup.

Inverters and charge controllers do not need maintenance. Portable solar chargers, generators and kits are also maintenance free. Just make sure portable solar systems are not drenched in water. Avoid dropping them or hitting against hard surfaces.

Above everything else, use your solar power system as indicated in the product guide. As long as you don’t overload the system there won’t be energy production problems.

What are the Advantages & Disadvantages of Solar Power?

The benefits of solar energy are plentiful.

  • Lowers electricity bills: if you’re on a grid tied system, expect your power bill to drop significantly once you start using solar power. Expand your solar power system and the power bill goes down even more. Off grid homes pay zero electricity bills.
  • Energy independence: you are no longer held hostage by power companies and spiking energy prices. You pay very little or nothing at all.
  • Energy on the go: RV solar panels lets you go anywhere and never lack for electrical power. Portable solar panels means you don’t have to leave your gadgets when you hike or go kayaking.
  • Clean energy: no pollution, no toxic elements, no greenhouse effects, no harmful effects on the environment
  • No noise: solar power systems run quietly.
  • Limitless supply: solar energy comes from the sun, a virtually infinite power source, always renewable and always present.
  • Availability: unless you live in Antarctica, you will always have access to solar power.
  • Good for our well-being: what is good for the environment is good for humans. Solar power systems are so clean you can put a solar generator inside your home without health risks.
  • Versatile: there are solar systems for homes large and small. There are also solar panels for RVs and solar chargers for mobile phones. They literally come in all shapes and sizes, whatever your needs.
  • Easy to use: once a solar power system is set up, you can forget abut it. The panel will go to work without supervision.

There are a few disadvantages though:

  • Cost: installing a home solar panel costs thousands of dollars. While the unit pays for itself over the long term, there’s no question you have to spend quite a bit first. The upfront cost however, continues to go down. What’s more, almost all states offer rebates and credits for solar powered homes.
  • Large space requirements: portable solar panels fit in your backpack, but 60-72 cell solar panels are 6-7 feet long and 3 feet wide. You’ll need space on your roof and assistance in setting it up. A solar panel array takes up even more space.
  • Weather dependent: if it’s cloudy, raining or overcast, solar panels won’t produce as much energy as you may like. Obstructions like tree branches could reduce performance too. Make sure the panels are set up in a clean, clear location.

If it isn’t obvious by now, the benefits of solar power outweigh the negatives. The biggest hindrance for many is the high upfront cost, but in 4 or 5 years you should break even. After that, money that you would use to pay for your electricity bill now goes in your pocket.

Conclusion

Solar power has overcome a lot of obstacles to become a truly dependable power source. It has so many things going for it – renewable, clean, limitless supply, low maintenance, availability – that it’s no surprise more and more people are adopting it. Whether you’re a businessman, homeowner or someone who wants free energy for phone charging, solar power can help.