How Does A Solar Battery Work?

Solar batteries can be an important addition to your solar power system. They help you store excess electricity that you can use when your solar panels aren't generating enough energy and give you more options for how to power your home.

If you are wondering how does solar battery works, this article will explain to you what a solar battery is, solar battery science, how solar batteries work with solar power systems, and the overall benefits of using solar battery storage.

What is A Solar Battery?

The solar battery is a device that you can add to your solar power system to store the excess electricity generated by your solar panels. You can then use that stored energy to power your home at times when your solar panels do not generate enough electricity, including nights, cloudy days, and during power outages.

The point of solar batteries is to help you use more of the energy your solar panels create. If you don't have battery storage, any excess electricity from your solar power goes to the grid, which means your solar panels are generating power and providing it to other people without taking full advantage of the electricity your solar panels create first.

The Science of Solar Batteries

Lithium iron phosphate batteries (LiFePO4 batteries) are the most popular solar batteries currently on the market. This is the same technology used for smartphones or other high-tech batteries. Lithium iron phosphate (LiFePO4) batteries work through a chemical reaction that stores chemical energy before converting it to electrical energy. The reaction occurs when lithium irons release free electrons, and those electrons flow from the negatively-charged cathode to the positively-charged anode.

The lithium salt electrolyte is a liquid inside the battery, which is encouraged and enhanced this movement by providing the necessary positive irons to balance the reaction. The flow of free electrons generates the current that people need to use electricity.

When you are drawing electricity from the battery, the lithium irons flow back across the electrolyte to the positive electrode. At the same time, electrons move from the negative electrode to the positive electrode by the outer circuit, powering the plugged-in device.

Home solar power storage batteries combine multiple iron battery cells with sophisticated electronics that regulate the performance and safety of the whole solar battery bank system. Thus, solar batteries function as rechargeable batteries that use the power of the sun as the initial input that kick-starts the whole process of creating an electrical current.

Comparing Battery Storage Technologies

When it comes to solar battery types, there are two common options, lithium-iron phosphate (LiFePO4) batteries, and lead-acid batteries. Solar panel companies prefer lithium-iron phosphate (LiFePO4) batteries because they can store more energy, hold that energy longer than other batteries, and have a higher depth of discharge. Also known as DoD, Depth of Discharge is the percentage to which batteries can be used, related to their total capacity. For example, if a battery has a DoD of 95%, it can be safely used up to 95% of the battery's capacity before it needs to be recharged.

Lithium-Iron Phosphate (LiFePO4) Battery

As mentioned earlier, battery manufacturers prefer lithium-iron-phosphate battery technologies for their higher DoD, reliable lifespan, and ability to hold more energy for longer and more compact sizes. However, because of these numerous benefits, lithium-iron phosphate (LiFePO4) batteries are also more expensive compared to lead-acid batteries.

Lead-Acid Battery

Lead-acid batteries (the same technology as most car batteries) have been around for many years, and have been widely used in home energy storage systems for off-grid power options. While they are still on the market at pocket-friendly prices, their popularity is gradually fading due to the low DoD and shorter lifespans.

AC Coupled Storage vs. DC Coupled Storage

Coupling refers to how your solar panels are wired to your batteries bank storage system, and the options are either direct current (DC) coupling or alternating current (AC) coupling. The main difference between the two is the path of the electrical energy produced by the solar panel.

Solar panel cells produce DC electricity, and DC electricity must be converted into AC electricity before it can be used by your home. However, solar batteries can only store DC electricity, so there are different ways of connecting solar batteries to your solar power system.

DC Coupled Storage

With DC coupling, the DC electricity produced by solar panels flows through the solar charge controller and then directly into the solar batteries. There is no current change before storage, and conversion from DC to AC only occurs when batteries deliver electricity to your home or back out into the grid.

DC-coupled storage batteries are more efficient because the electricity only needs to change from DC to AC once. However, DC-coupled storage typically needs a more complex installation, which can increase the initial cost and lengthen the overall installation timeline.

AC Coupled Storage

With AC coupling, DC electricity generated by solar panels goes through an inverter first to be converted into AC electricity for everyday use by appliances in the home. That alternating current  (AC) can also be delivered to a separate inverter to be converted back to direct current (DC) for storage in the solar batteries bank. When it is time to use the stored energy, the electricity flows out of batteries and back into an inverter to be converted back into AC electricity for your home.

With AC-coupled storage, electricity is inverted three times separately, one is when going from solar panels into the house, another when going from the home into batteries bank storage, and a third time when going from batteries storage back into the house. Each inversion do causes result in some efficiency losses, so AC-coupled storage is slightly less efficient than a DC-coupled system.

Unlike DC-coupled storage, which only stores energy from solar panels, one of the biggest advantages of AC-coupled storage is that it can store energy from both solar panels and the grid. This means that even if your solar panels are not generating enough electricity to fully charge your batteries bank, you can still fill the battery with electricity from the grid to supply you with backup power or take advantage of electricity rate arbitrage.

It is also easier to upgrade your existing solar power system with AC-coupled battery storage, because it can be added on top of an existing system design, instead of needing to be integrated into it. This makes AC-coupled battery bank storage a more popular option for retrofit installations.

How Solar Batteries bank Work with a Solar Power System

This entire process starts with solar panels on your roof generating electricity. there is a step-by-step breakdown of what happens with a DC-coupled system:

Sunlight hits the solar panels and the energy is converted into direct current (DC）electricity. The electricity goes into the battery and is stored as direct current (DC) electricity. The DC electricity then leaves the battery and goes into the inverter, where it is converted into AC power that the home can use. The process is slightly different from AC-coupled systems.

The electricity goes into the inverter to be converted into alternating current (AC) electricity the home can use. The excess electricity then flows through another inverter to change back into direct current (DC) electricity that can be stored for later.

If your house needs to use the energy stored in the battery, that electricity must flow through the inverter again to become alternating current (AC) electricity.

How Do Solar Batteries Work with a Hybrid Inverter?

If you have a hybrid inverter, a single device can convert direct current (DC) electricity into alternating current (AC) electricity and can also convert AC into DC. Thus, you don't need two inverters in your photovoltaic (PV) system. One is to convert electricity from solar panels (solar inverter) and another is to convert electricity from solar batteries (battery inverter).

Hybrid inverters, also known as battery-based inverters or hybrid grid-tied inverters, combine battery inverters and solar inverters into a single piece of equipment. It eliminates the need to use two separate inverters in the same setup by functioning as an inverter for both the electricity from your solar batteries and the electricity from your solar panels.

Hybrid inverters are growing in popularity because they can operate with or without battery storage. During the initial installation process, you can install a hybrid inverter into a battery-free solar system, which gives you the option to add solar energy storage down the line.

Benefits of Solar Battery Storage

Adding battery backup for solar panels is a great way to ensure you get the most out of your solar power system. there are some of the main benefits of a home solar battery storage system:

Stores Excess Electricity Generation

Your solar panel system can often create more power than you need, especially on sunny days when no one is at home. If you don't have solar energy battery bank storage, the extra energy will be delivered to the grid. If you participate in a net metering program, you can earn credit for that extra generation, but it is usually not a 1:1 ratio for the electricity you generate.

With battery storage, the extra electricity charges up your batteries for later use, instead of going to the grid. You can use the stored energy while times of lower generation, which reduces your reliance upon the grid for electricity.

Provides Relief from Power Outages

Since your batteries can store the excess energy produced by your solar panels, your home will have electricity available while power outages and other times when the grid goes down.

Reduces Your Carbon Footprint

With solar panel battery storage, you can go green energy by making the most of the clean power created by your solar panel system. If that energy is not stored, you will rely on the grid when your solar panels don’t generate enough for your needs. However, most grid electricity is created using fossil fuels, so you will likely be running on dirty energy when drawing from the grid.

Provides Power Even After the Sun Goes Down

When the sun goes down and solar panels are not generating electricity, the grid steps in to provide much-needed power if you don’t have batteries bank storage. With solar batteries, you will use more of your solar power at night, giving you more energy independence and helping you keep your electric bill low.

A Quiet Solution to Backup Power Needs

Solar power batteries are one hundred percent noiseless backup power storage options. You can get the benefit from maintenance-free clean energy, and don’t have to deal with the noise that comes from a gas-powered backup generator.

Key Takeaways

Understanding how solar batteries work is important if you are planning to add solar panel energy storage to your solar power system. Because it operates like a large rechargeable battery for your home, you can take advantage of any excess solar energy your solar panels produced, giving you more control over when and how you use solar energy.

Lithium-iron phosphate (LiFePO4) batteries are the most popular type of solar battery and work through a chemical reaction that stores energy, and then releases it as electrical energy for use in your home. Whether you are choosing a DC-coupled, AC-coupled, or hybrid system, you can increase the returns on investment of your solar power system without relying on the grid.

Conclusion

Whether you are installing a new solar power system, or already have one, solar energy battery storage can help you get the most from your systems. Solar batteries store excess electrical energy that panels create. These batteries provide steady power backup while periods of outages or after sunset. On one hand, you can save a lot of grid costs from a solar system. On the other hand, if you are buying a battery bank to store solar energy then you can claim a 30% federal solar tax credit on it (Please consult your local tax authority for details).

Installing solar batteries is a great option for those people who are living in areas with frequent power outages. Also, they are worthwhile in areas where there is an incentive to use solar batteries. Solar batteries are great for the environment, making them one of the most important investments in our ecological future.