Solar panels are often the first thing that comes to mind when thinking about solar. After all, they’re the most visible component and definitely one of the most important. Solar panels are low-maintenance, long-lasting, reliable, available in different forms, and they help you lower your carbon footprint. And contrary to noisy, dirty gas-powered generators, solar panels are a greener option that also happen to be virtually silent.
Overview: Solar Power
How to Select
How to Size
How to Install
With a wide range of solar panels in the marketplace, there’s never been an easier time to go solar. From portable folding solar panels for an RV to kits created just for an off-grid cabin, there’s most likely a product already crafted just for you and your specific needs. In this guide, we’ll be talking about everything there is to know about solar panels, including how solar panels work, the difference between panel types, and choosing the best panels for your system.
What is solar power?
Solar installations are made up of three main functions: collection + storage = usage. The more you want to use, the more you must collect and store. There are four essential components which make this process safe and efficient: solar panels, charge controllers, inverters, and batteries. Solar panels collect the energy, battery banks store that energy, and then you use charge controllers and inverters to make that energy usable by appliances and devices in your home.
Photovoltaic solar panels themselves are made up of many solar cells made of silicon. These cells have both a positive and a negative layer, which creates an electric field. When sunlight hits your solar panel, it creates an electric current. This current, pushed by voltage, passes through the wires and components in your system. Then when you plug an appliance, voila!
What are the different types of solar panels on the market?
When shopping for solar panels you’ll have to choose between monocrystalline and polycrystalline panels, flexible and rigid panels, and portable and roof-mounted panels.
Monocrystalline Vs. Polycrystalline Solar Panels
Monocrystalline and polycrystalline panels are physically unique. Monocrystalline panels are a dark grey, almost black, whereas polycrystalline panels are a light blue.
But it’s not just an aesthetic difference. Monocrystalline panels are typically more efficient than polycrystalline, but they are also more expensive. To pick between the two, you’ll want to consider your priorities. Many people prioritize aesthetics and prefer the darker monocrystalline panels because they blend in better on a dark roof. If you are building an installation with very limited space, you’d probably want to purchase monocrystalline panels because they are more energy and space efficient. If money is the driving factor, you may choose to go with the less expensive polycrystalline panels. Learn more about the two types in the blog post below.
Flexible Vs. Rigid Solar Panels
Rigid, roof-mounted panels are the most common solar panels on the market. The main benefits of rigid solar panels is that they are durable and can be mounted at angle. This increases their overall energy production efficiency. Renogy has rigid solar panels in varying sizes, from 30 to 300 watts.
If you’re looking for a way to mount your panels to a non-flat roof, you might want to consider flexible panels. Flexible solar panels weigh less than the rigid solar panels and can be installed directly on the roof of your RV, in contrast to rigid solar panels which stick up above your roof somewhat and can be trickier to place between other components on your roof. Flexible solar panels typically weigh a quarter of the weight of traditional rigid panels, but it’s important to note that due to the nature of plastic, flexible solar panels typically degrade more quickly than glass and aluminum found in rigid solar panels.
Portable Vs. Roof-Mounted Panels
Portable solar panel kits can be a great solution for those not quite ready to install a solar system on their roof, have limited space, want to generate solar while both on the open road or at home, or who have smaller energy needs. Portable solar panel systems are typically available as folding suitcase panel kits that can be set up on the ground and angled for maximum efficiency. They are lightweight and easy to handle, making them ideal for those travelling. That being said, roof-mounted panels are ideal for those with consistent and sizeable energy needs and want to be able to charge at any time.
Ground mount or roof mounted solar panels? Which are better?
Roof-mounted panels are the most common type of solar panel installations. Ground mounts are attached to a secure structure connected to the ground with steel beams. Ground mounts are often installed when roof mounts can’t be completed due to shading, roofing, or space issues.
Ground mounts can be installed at multiple angles or at any direction for optimal energy production, and are easily accessible for maintenance and cleaning. That said, installation is typically more labor intensive and expensive and permitting is more complex than roof mounted panels. Some people don’t find ground mounted panels aesthetically pleasing and take up real estate on the ground.
How do I select a solar panel kit?
Although it may seem intimidating at first, adding solar to your home, boat, van or RV is actually quite easy. Renogy solar panel kits make it easy to ensure all the components of your system are compatible. Then, once you have it all set up, it’s just a matter of flipping the switch and you’ll be generating power in no time. Check out the blog posts in this section to learn about the various solar panel kits available through Renogy and whether or not they’re right for you.
Should I choose 12v or 24v solar panels?
When designing your solar installation, you’ll have to choose between a 12, 24, or 48 volt system. 12 volt solar panels are the most common, but are they the right panel for you?
12v systems are good for many DIY solar scenarios and suitable in RVs, motorhomes, vans, camper trailers, and small cabins or tiny homes. RVs and motorhomes typically already have 12 volt batteries for lighting, hot water heater controls, AC/heating controls, and refrigerators. Therefore, it makes sense to use the voltage that already works for that system.
24 volt systems are suitable for large homes and apartment buildings, commercial and industrial buildings, and parking structures. If your energy needs are around 1,000 to 5,000 watts, go for a 24 volt system. If your energy needs are over 3,000 watts, go for a 48 volt system. Large off-grid houses often use 48V.
How long do solar panels last?
Renogy framed solar panels have a performance warranty of 25 years. The loss of performance is typically 1% per year. After five years, Renogy panels should still output at least 95% of the rated power, after 10 years they should output 90%, and after 25 years 80%. Be sure to register your warranty on the Renogy page shortly after purchasing your components.
How do I care for solar panels?
Another great thing about solar panels is how little maintenance they require. We encourage you to wash off the panels at least once a year to remove any dirt or other residue that may have collected on the panels. It’s also a good idea to visually examine the panels at that time to make sure all connections are in place and in working condition. If you live in an area with heavy snow, you’ll also want to make sure you clear your panels of snow if it starts to accumulate. Solar panels will typically generate enough heat to melt down any smaller snowfalls. Learn more maintenance tips in the blog post below.
How do I know if my roof is good for solar?
If mounting solar panels to your roof, you’ll want to ensure your roof is in suitable shape to hold solar panels. If your roof is nearing the end of its lifespan, you’ll want to replace your roof before installing solar. A solar panel system will last you 30 to 35 years. If your roof is between five and 10 years from needing replacement, it’s a good idea to hire a professional to assess the condition of your roof.
Every roofing material has a slightly different lifespan. As some general guidelines, clay tile, slate, and copper roofs can last up to 50 years, wood shake roofs have about a 30 year lifespan, and cement shingles last about 20 years. Replacing your roof before installing solar means you won’t have to tear everything out just a few years into having your installation, which will save you lots of money in the long run.
What else should I do before going solar?
Before you install solar, you’ll want to do three main things.
- Assess your roof if you’ll be mounting panels: Again, if your roof is nearing the end of its lifespan, you’ll want to hire a consultant to examine your roof and/or replace your roof to prep for roof-mounted panels.
- Conduct an energy audit to determine how you can make your home more energy efficient: A home energy audit is an easy and powerful way to determine where your home is losing energy and what steps you can take to improve your home’s efficiency. Audits should always be the first step before installing a system to determine how you can make sure your panels aren’t just collecting energy that’s going to be wasted to do inefficiencies within your home.
- Size your system to determine what components you’ll need: It’s essential to take the time to size your system. If you overbuild your system, you’ll waste thousands of dollars on capacity and components you don’t even need. If you underbuild your installation, your system won’t be able to meet your needs. The key here is to design your system with just the right amount of capacity. To achieve that we recommend using the Renogy solar panel calculator to determine what size system you should build to meet your energy needs.
- Tips for a Safe Solar Installation
How many solar panels will I need?
It’s incredibly important to properly size your solar installation. Undersize your system and you won’t meet your energy needs. Oversize it and you’ll waste money on components you’re not using. To determine what size system will best fit your needs, we recommend using the Renogy solar panel calculator. The solar sizing calculator allows you to input information about your lifestyle and appliances used. The solar panel calculator will then be able to tell you the minimum and recommended system size, as well as the recommended battery output.
How many solar panels do I need to go off-grid?
Sizing an installation is always important, but it is absolutely crucial in an off-grid system where you’re relying solely on your solar system. To give you an idea of how many panels you might need, we’ll give you an example. Let’s say you have some 300 watt solar panels, and you’re looking to provide power for your home. You don’t have access to the grid and installing off-grid solar on your home is your best option for meeting your energy needs.
Let’s assume that each panel gets around 8 hours of sunlight per day on your rooftop. A 300 watt panel receiving 8 hours of sunlight per day will produce almost 2.5 kilowatt-hours per day. If we multiply this by 365 days per year, we get a solar output of about 900 kilowatt-hours annually. In short, each panel will provide 900 kilowatt-hours each year.
How much energy does your home use? Most data suggests that a typical American home (2,000 square feet home) consumes approximately 11,000 kilowatt-hours annually. So, when we divide our total consumption by the expected output of one solar panel, we see that roughly thirteen solar panels of this size would be enough to power a home of that size. Of course, if you have a smaller home or are powering an RV, your energy needs will be much lower, and you’ll need fewer panels.
How large are solar panels? Are they difficult to handle?
Solar panels vary in size depending on the specific product and wattage of the panels. Renogy 100 watt 12 volt panels for example are 42.2 inches X 19.6 inches X 1.38 inches. This is in comparison to the 200 watt 12 volt panels which are 63.8 inches x 25.9 inches x 1.4 inches.
Flexible solar panels are more lightweight and easier to handle. Renogy 100 watt 12 volt flexible solar panels are 48 inches x 21.6 inches x 0.08 inches. Many people choose to select flexible solar panels because of their ability to be mounted on non-flat surfaces. Many van or RV dwellers also prefer them because they can be mounted flush to your roof and stay out of view from passersby. This can be important if you’re stealth camping and don’t want people to know that someone is living inside and/or operating solar panels.
What is the lifespan of solar panels?
Renogy panels come with a 25-year power output warranty. Within five years, they guarantee a 95% efficiency rate, at 10 years a 90%, and at 25 years of age will still operate at 80% efficiency. Panels also come with a 5-year material and workmanship warranty.
How is solar panel efficiency rated?
Panel efficiency measures your solar panel’s ability to convert sunlight into electricity. If two panels are in the same amount of sunlight for the same period of time, the panel with a higher efficiency rating will produce more electricity than the less efficient panel. Efficiency is determined by the production of electricity by solar cells. Efficiency is very important if you have limited space to work with. As mentioned earlier, monocrystalline panels are the most efficient solar panel option.
Can I install solar panels on my own?
Yes! Installing a small-scale, off-grid solar system can easily be done on your own. Renogy’s solar panel kits make it easy to install a solar installation on your own by including most of the necessary components you’ll need, including solar panels, a charge controller, mounting hardware, combiner boxes, and circuit breakers.
You’ll still need to purchase batteries and an inverter. If you’re wanting to install an on-grid system, you’ll want to check with your state energy office, local officials, or a local renewable energy organization to see what rules, regulations and building codes exist.
What can you run with a 300 watt solar panel?
A 300 watt panel that receives 8 hours of sunlight per day will produce almost 2.5 kilowatt-hours per day. If we multiply this by 365 days per year, we get a solar output of about 900 kilowatt-hours annually. In short, each panel will provide 900 kilowatt-hours each year.
Considering all of the different scenarios, there is still a long list of appliances and devices that can run effectively with 300-watt solar panels, including laptops, LED lights, stereos, and TV’s.
To get an accurate calculation of what you can and cannot power with a single 300 watt solar panel, you’ll need to compare the output per day or month (so 2.5 kWh/day for the solar panel) with the needs of an appliance (3.8kWh/day for a refrigerator). In this example, a 300 watt solar panel would not be enough to power that refrigerator.
How long does it take solar panels to charge a battery bank?
Your batteries’ charging time depends on a variety of factors: charge status of the battery, size of the battery, number of batteries, wattage output and number of panels, availability of peak sunlight, weather conditions, and time of year.
A 12 volt, 100 amp hour battery will provide 1200 watt hours. Charging that battery from 50% to 100% capacity with one 100 Watt solar panel requires 6 hours of peak sunlight. Charging that same battery with two 100 Watt panels requires 3 hours of peak sunlight. Your batteries will still charge outside of peak sunlight hours, but your solar panels just may not produce maximum output during that time. Learn more about what size panels to purchase for your battery bank in the blog post below.
Put It All Together
Going solar is a great way to become energy independent, save money on monthly utility bills, and ensure reliable access to energy whenever you need it most. Regardless of if you’re looking to buy a portable solar panel kit for your RV or are ready to take the plunge and install an off-grid system on your home, taking the time to learn about your different panel options will ensure you’ll build a strong foundation for your solar installation.