Why Solar Panels Use Direct Current
Solar panels produce direct current electricity, which is a natural byproduct of the photovoltaic process, the mechanism they use to power appliances and electrical systems. However, most homes and appliances require AC power. Inverters are necessary to convert the power and bridge the gap between DC generation and AC consumption.
Make sense of the photovoltaic process and the conversion of DC power into useful AC energy so you can choose the right solar installation for your home.
Understand the Photovoltaic Effect: Converting Sunlight to Direct Current
When you have solar panels set up outside, photons from sunlight strike the photovoltaic cells within each panel, which contain a semiconductive material. This photon energy knocks electrons loose from the semiconductor (usually silicon) atoms in the PV cells, and the free electrons begin to create an electrical charge. This is called the photovoltaic effect.
The free electrons flow in a single direction from the negative to the positive side of the cell, and this consistent, unidirectional flow is what defines a direct current.
Key Mechanisms in PV Cells
There are three mechanisms in the PV effect that produce direct current. First, the photons from the sun must be absorbed by the semiconductive cells. Then, they must liberate electrons from the cells, and finally, they form a direct current.
In the absorption process, the solar cells on the panel's surface are penetrated by photons from sunlight, transferring energy to the electrons.
As the process transitions into electron liberation, they become free from their previous atomic bonds and become mobile charge carriers. The cell’s structure creates an electric field, directing electron movement from the positive to the negative sides of the cell. All of the electrons begin flowing consistently through the circuit in this way.
This directional flow becomes a direct current that remains constant as long as sunlight is hitting it. However, the voltage and amperage of the current may fluctuate based on the cell’s efficiency and the sun’s intensity.
You can combine multiple solar cells in series or in an array to achieve your desired voltage and current output.
Inverters and System Architecture: Turning DC into Usable AC
At this point in the process, you have ample DC energy flowing through your photovoltaic system. However, as we mentioned earlier, most homes and their appliances require electricity from the AC power source. The grid also operates on AC power for efficiency in long-distance transmission. So, how do we turn the DC into usable AC?
This is where the inverter plays a key role.
The inverter takes the DC electricity produced by solar panels and rapidly switches the current back and forth, creating a waveform that mimics AC power and makes it compatible with existing electrical infrastructure, both at home and throughout the grid. The inverter is a crucial bridge between what your panels generate and what your home consumes.
Most inverters have efficiency ratings around 95-98%, meaning you lose about 2-5% of energy during the conversion. This is minimal, but usually unavoidable. The higher the quality of your equipment, the less resistance the energy will face during the conversion process, and the less power you’ll lose.
Choosing a higher-efficiency converter reduces your system’s overall energy waste.
DELTA 3 Max Plus Portable Power Station
Types of Inverters in Solar Systems
When choosing an inverter for your home solar system, you have the options of a microinverter, string inverter, or hybrid inverter.
A microinverter is an individual inverter that attaches to each solar panel to convert the DC to AC at the panel level immediately upon production. Each panel operates independently to minimize the impact of debris or shading on a single panel. This method can also maximize your overall system output, but it’s more expensive upfront.
The multiple failure points also leave you more vulnerable. However, if you expect to expand your system down the road, this can still be a good choice because you won’t be limited by inverter capacity.
A string inverter is the most common inverter you’ll see in residential and commercial applications because it utilizes a single inverter unit that processes power from multiple connected panels. It’s a cost-effective choice if your system experiences consistent sunlight exposure and you prefer a simpler installation with fewer components. The downside is that if one panel underperforms, it can impact the entire string output.
A hybrid inverter combines the functionality of a solar inverter with the benefits of a battery management system. It handles inputs from both your solar panels and battery storage, like the EcoFlow DELTA 3 Max Plus (2048 Wh), enabling you to store energy for later use. It’s an excellent option for backup power or those seeking energy independence. You pay for the added versatility with a higher up-front price.
Compare AC vs DC: Choosing the Right Configuration for Your Home and Grid
AC power has dominated electrical grids since the late 1800s. AC is required if you want a grid-tied system, plan to leverage net metering programs, or power standard household appliances. However, DC power excels at battery storage and can be transmitted directly from the solar panel to the battery without incurring conversion loss.
DC power has seen a resurgence for off-grid systems and specific devices like EVs. Still, most modern systems use both: AC for the grid/appliances, and DC for storage.
Frequently Asked Questions
Which Is Better, AC or DC Solar Panels?
All solar panels inherently produce DC electricity. The term ‘AC panels’ may refer to panels with individual microinverters to convert the energy into AC, or it may refer to solar arrays that use a string inverter to convert the total energy produced into AC for the home or the grid.
Why Don’t Solar Panels Produce Alternating Current?
Solar panels inherently produce direct current energy; it is a natural physical phenomenon that occurs when photons from sunlight liberate and excite the electrons on semiconductor cells within the panels. It cannot be altered.
Can I Run My Home Entirely on DC from Solar Panels?
Running your entire home on DC from solar panels is technically possible, but it is impractical and too expensive for most homes. It would require you to replace all appliances with DC equivalents and eliminate any grid connection.
Final Thoughts
Solar panels naturally produce DC energy through the phenomenon of the photovoltaic effect. This is what makes inverters so necessary; they convert the direct current of electrons into an alternating current that your home and appliances can use. AC power is also required for grid connection, but DC offers unmatched storage efficiency.
Combine both when you connect a solar array to the EcoFlow DELTA 3 Max Plus (2048 Wh), allowing you to use solar power immediately while storing any excess energy directly in the battery for later use.