Questions about solar? Over the years, we have compiled our customers’ most frequently asked questions (FAQs) about solar. The perfect place to get started for unbiased information so you can make the best decision.
Want more information on Integrated PV Systems? Feel free to contact us.
How many solar panels and what size are enough to meet my power need requirements?
Each energy consumer has different needs, dependent upon the electric appliances being run. For instance, if you are powering two 27 watt compact fluorescent light bulbs for two hours, you would need to supply 108 watt-hours of energy (2x 27x 2 hours). In San Diego, which has a yearly average insolation of 5 hours a day, one 32 watt photo voltaic (PV) module is more than adequate (32x 5 hours=160 watt-hours).
To find out how much energy you use, contact us, we would love to help you.
What if there is hardly any sunshine for several days?
Most solar electric systems today are connected to the utility lines - allowing you to send energy back to utility grid turning the meter backwards, or using power from the utility at times when there is no sunshine including when its dark outside. This connection to the utility grid ensures you will always have power to your home or business.
Different geographic areas provide different amounts of daily sunshine. For instance, the American Southwest averages 5 sunshine hours per day and the Northeast receives about 3 hours of daily sunshine. More solar panels will increase the amount of power generated when the sun is shining. Solar Electric sizes each system based on your area and also takes into account, shading from trees and other obstructions on your roof or surrounding area for optimal year-round performance.
How long do solar panels normally last?
New solar panels have a manufacturer's warranty of 20 years. With proper care, however, the panels should last many years beyond the warranty. You can expect your solar modules to continue to produce power for 60 years or more.
What maintenance is required for a solar electric system?
Solar electric systems are elegantly simple. Maintenance includes:
- Occasional checks of the connections between the solar modules and the inverter(s), and to tighten them when applicable.
Do some solar panels generate more power per inch than others?
Some solar panels do generate more power per inch than others. For example,
- Monocrystalline panels have a higher output per square foot than amorphous silicon panels. Traditionally, if square footage was important, monocrystalline solar modules were the best choice due to a higher conversion rate of sunlight to electricity.
- New amorphous silicon panels <link to UniSolar panels in the store> absorb three different spectral wavelengths, which translates to up to 30% more real power per watt from the PV module. This is because the amorphous panels produce energy for longer periods each day than monocrystalline panels. This means the panels produce more amp-hours per amp than other technologies.
New and future hybrid designs employ the best of both technologies
How can I find out how many watts my appliances use, such as computers and stereo etc.?
There are a few ways to determine how much energy your household appliances use including the following:
- The easiest way is to look at a monthly utility bill. This has the amount of kilowatt-hours consumed during the billed month. From there, a consumer can determine how many average kilowatt-hours were used daily.
- Additionally, a typical electronic appliance should have an energy rating sticker somewhere on the product.
- There are devices available including the Kill-A-Watt that can be used to determine the energy usage of a specific appliance.
How long does it take for a solar system to pay for itself?
The payback period for a solar system is roughly 5-7 years, based on calculations assuming the cost of energy obtained from the utility grid is 10 cents a kilowatt-hour.
What is the difference between a Solar Lease and A PPA (Power Purchase Agreeement)?
While the terms “solar leases” and “solar PPAs” are generally used interchangeably, there are subtle differences between the two. Monthly payments for both options are likely to be very similar. Both options can save you money over what you pay your utility and both options will protect you against rising electricity costs.
With a solar lease, you agree either to pay a monthly “rent” or lease payment in exchange for the right to use all of the power produced by the system.
A solar power purchase agreement (PPA) is similar to a solar lease but differs in one key way. Instead of "renting" the system and receiving the benefits of using it, you instead agree to buy the power generated by the system at a set price per kWh.
Is the current technology more advanced than a few years ago?
The technology behind PV solar energy is continuously improving. Research on thin film materials, processes and devices are leading to increased module efficiencies while using high-throughput, lower-cost plasma processing. Increased module efficiencies coupled with fast deposition rate technologies implies the cost of PV modules will continue to decline.
Do current trends show that solar electricity will become increasingly affordable?
Thin-film modules are less-expensive to manufacture because the amount of materials, capital investment and labor are decreased. According to the US Department of Energy's Fiscal Year 1998 Photovoltaic Energy Program Overview, researchers predict that by optimizing processes and using materials more efficiently, the cost of thin-film manufacturing could drop to $50 a square meter
Why choose solar over wind- or water-power generation?
Every energy source has its advantages and disadvantages. Wind- and water-power generation may be appropriate in certain situations. However, these technologies are
- Limited by seasonal variations
- Have moving parts that require maintenance
- Generate noise
- May negatively affect wildlife
PV modules, on the other hand, are:
- Silent
- Have no moving parts
- Non-glass panels are covered by a 20-year warranty.
Should I use a sine-wave or modified sine-wave inverter?
A modified sine-wave inverter is appropriate for most stand-alone household applications. However, for certain technical appliances or for grid-integrated PV systems, a central sine-wave inverter or micro-inverter is necessary. In grid-integrated systems, energy can be bought and sold to the utility company by the end user.
What is the difference between a micro-inverter and a central inverter?
Micro-inverter. A micro-inverter consists of a small box located on the back of or situated very close to a solar panel. Its role is to convert the DC electricity produced by a single solar panel. Features of a micro inverter:
- Ability to use different makes/models of modules in one system, particularly when repairing or updating older systems
- No need to calculate string lengths – simpler to design systems
- Increased yield from sites that suffer from overshadowing, as one shadowed module doesn’t drag down a whole string
- Allows for increased design flexibility, modules can be installed facing different directions - east, west or south - making the most use of your roof space.
- Lower DC voltage. No need for ~ 600 V DC cabling requiring conduits
- Panel level monitoring
- Parallel operation - in rare instances of failure, that single panel will not produce panel while the remaining panels will continue to produce electricity.
- Panel level MPPT (Maximum Power Point Tracking)
String inverters. A string inverter is the type most commonly used in home and commercial solar power systems. It is a box that is often placed near your electric panel. Depending on the size of the installation, there may be more than one string inverter present. String inverter advantages:
- Remote system monitoring capabilities
- Low cost
- 3 phase variations available
- Robust
- High efficiency
- Allows for high design flexibility
Central inverters. Central inverters are designed for large-scale commercial, industrial, government and field applications – Basically, they are a very large string inverter.
What is the difference between a parallel AC system and a series DC system?
The simplest way to think about series vs. parallel systems is thinking about a string of Christmas lights - when one bulb went out, the whole string went out. That is a series system. When one solar panel is shaded, a panel or inverter malfunctions - the entire string goes down. On the other hand, with a parallel system, when that bulb goes out, that single bulb is the only one out and the rest of the string continues to work.
Series-wired systems are governed by the principles of voltage. A solar array must provide a high enough voltage to enable its inverter to operate at an efficient level and all series-architected solar installations conform to an exact footprint used for the entire array. Best suited for large rooftop and field installations where all the modules are at a the same angle, facing the same direction and in the same location. Parallel-wired systems are not limited by voltage principles or footprint restrictions are best suited for more complicated installations.
What is the difference between EnPhase Micro-inverters and SolarEdge Power Optimizers?
Both are micro-inverters that offer up to 25% increase in the amount of energy they are able to harvest. SolarEdge has a higher 98.3 peak, 97.5% CEC inverter efficiency. Both offer individual solar module monitoring via the Internet on your smart phone or computer.
Power Rating. EnPhase is rated at 250 watts while Solar Edge offers a power rating up to 300 watts, ensuring that no power is wasted with larger solar modules.
Electrolytic Capacitors. SolarEdge does not use any electrolytic capacitors in their under module mounted power optimizers.
String System. A disadvantage of Solar Edge inverters is that they are string inverters, which means if one fails - the entire string fails - much like the old Christmas lights where if one bulb went out, none of the lights work.
Are prepackaged ready to go systems available?
PV systems are increasingly being designed for ease-of-use. Prepackaged turnkey (plug-and-play) solar systems are available, and can be custom-designed by Solar Electric fora variety of power projects.
What are the benefits of a micro-inverter?
The homeowners who are more affected by shading are also those that can benefit the most from micro-inverters. Micro-inverters are also excellent for difficult roof orientations - including those installations where panels facing different directions of east, south or west, starter systems and small applications.
- Individual Optimization
- Maximum Power Point Tracking (MPPT)
- Longer Warranty
- Easily Expandable
- Performance Reports
- No Single Point of Failure
- Improved Safety
- Silent
To many, solar is a fascinating but confusing technology.
There are so many factors to think through and variables to consider.
It would be enough to make anyone’s head spin.
That’s where we come in!
Take this blog post with you!
In today’s post, we break down the main aspects of developing a solar solution making the prospect more approachable (Want to learn more about our specific custom solar design process? Read this post on that exact topic).
Nearly every solar solution contains six main components.
1. Load (How much energy will it take to power my device/system?)
2. Environment (Where will the device be operating?)
3. Technology (What solar technology provides what I need for my application?)
4. Sizing (How much solar is necessary?)
5. Charge controller (What means of charging protection/optimization is best?)
6. Battery (What battery size/chemistry makes the most sense for my application?)
Load
While it might seem simple to determine how much power your device consumes, after a little research, it can be dizzying and frustrating.
To tackle this difficult problem, take a look at two previous posts dedicated to learning about your power budget and calculating your exact power budget.
After reading through these posts and taking careful notes, you learned how much power your device uses, and you’re ready to move forward.
Environment
When determining what type of solar is best suited for your application, the particular environment plays a key role.
There are two primary environments where a solar solution can function.
Below are the main considerations looking at outdoor and indoor solar panels.
Outdoors
Shading vs. direct sunlight
Where is the exact location that you will deploy your solar solution? Will there be obstructions for large portions of the day? (Check out this blog post, which dives into how shading can affect solar output and inform what solar technology to use).
How much sunlight is available per day?
Where are you located? How much sun can you expect to receive on an average day? (Calculate how much solar you can expect in your location using NREL’s PVWatts Calculator).
Weatherproofing
Will your solar panel be in a wet environment? Does it need to be IP67 rated? If so, you will want a fully encapsulated solution designed for exposure to water. (Check out our Rollable Solar Panels designed for use in the marine environment. For smaller or more custom applications, check out our WeatherPro Series Electronic Component Solar Panels).
Are you interested in learning more about bipv solar panels price? Contact us today to secure an expert consultation!
If the solution is used for short periods and then packed up, a solution that isn’t wholly encapsulated will work. (Check out of Foldable Solar Panels designed for rapid deployment For smaller or more custom applications, check out our Classic Application Series Electronic Component Solar Panels).
Indoors
Did you know solar panels can function indoors? They can! (Check out this post comparing Outdoor and Indoor Solar Panels to learn more).
Do all solar technologies work indoors?
All solar panels do not function the same when used in an indoor environment. To learn which solar technology will perform best indoors, check out this post comparing portable solar technologies, including their low-light performance.
Lux levels of typical locations
When you determine which solar technologies will work for your indoor application, it’s essential to determine how much light is available in your space. This will help refine the technology that is best suited for your specific spot.
Technology
There are many different solar technologies available. Today, we will be focusing on three of the most popular, including Amorphous Silicon (a-Si), Crystalline Silicon (c-Si), and Gallium Arsenide (GaAs).
Amorphous Silicon (a-Si)
Amorphous Silicon is ideal for low power indoor/outdoor IoT applications and where rugged portability is a critical requirement. a-Si is well suited for designs that take advantage of the thin, flexible, and lightweight nature of the material (Learn more about a-Si).
Crystalline Silicon (c-Si)
Like traditional rooftop solar, this technology is well suited for medium to high power applications where power density is critical. Using high-efficiency SunPower solar cells, this technology offers a cost-effective solution (Learn more about c-Si).
Gallium Arsenide (GaAs)
This technology features conversion efficiencies of over 30 percent. It is well suited for applications where power density and ruggedness are critical, and the cost is not a factor (Learn more about GaAs).
Want to learn more about these solar technologies? Visit our Technology page.
Sizing
Before digging too deeply into what panel size or technology to choose, it’s essential to know the difference between a conventional power supply (an outlet in your home, for instance) and a solar panel.
Additionally, you can see what’s possible by building your ideal Electronic Component Solar Panel using our Custom Solar Panel Design Tool.
For space-constrained applications, c-Si or GaAs can provide more power in a smaller area than thin-film PV (a-Si).
Now that you know how much power you need, we can determine how much solar it will take to satisfy your power demands.
Don’t stress. We are here to ensure you get the perfect sized panel for your needs.
Learn more about the differences between crystalline silicon and amorphous silicon (Both technologies we can offer for your solution).
Charge Controller
You might think you can connect a solar panel to your device, and you’ll be okay. While that can be true, the majority of the time, it’s a bit more complicated.
For indoor and low power IoT applications, an energy harvesting PMIC is an effective solution. Check out our development kits, which make prototyping simple.
For medium to high power outdoor applications, there are many excellent charge controller options.
The first step is determining when you need to use a charge controller.
Next, learn how they maximize the energy your solar solution collects.
Finally, select the controller that will work best for your specific application.
Battery
You’ve determined your power budget, selected the right solar technology, and know which charge controller will work best for you.
Now what?
The last step is to determine which battery will act as an intermediary between the solar panel and your electronics.
Batteries are almost always necessary because whether we like it or not, the sun doesn’t shine 24 hours/day.
There are different battery chemistry options to choose from, and selecting the proper battery is crucial in creating a solution that will perform at a peak level.
How do you determine which battery and what size will be best for you? Take a look at our post covering this exact topic to start.
With this knowledge in hand, we’ll talk through the various options allowing you to make an informed decision.
There you have it. You’ve worked through the six questions!
Designing a solar solution from the ground up can be daunting.
We get it.
We’re here to help.
We’ll walk through the six questions above, help you every step of the way, and ensure you have the best possible solution. (Want to learn more about our specific custom solar design process? Read this post on that exact topic).
Do you want to learn more about what we offer and how we can simplify the process?
Contact us today!
We look forward to working with you!
Take this blog post with you!
If you are looking for more details, kindly visit bipv solar roof tiles.