How Do Solar Batteries Work?

How Do Solar Batteries Work?

How Do Solar Batteries Work?

If you are interested in optimizing the performance of your solar system, then you might be considering installing a solar battery. Doing so will enable you to start utilizing the excess energy that your solar panels produce, which can save you money on your energy bill.

However, before you buy, you might be searching online for things like “how do solar batteries work?” or “how to store solar energy”. If so, you have come to the right place. Keep reading to learn:

  • Everything that you need to know about how solar batteries work
  • Why it could make sense for you to add a battery to your system
  • Alternatives to solar batteries that you might also want to consider
  • And much more

How do solar batteries work?

Solar batteries are built to store the excess energy that your solar panels create. To see exactly how this works, let’s break it down into steps.

1. Your panels generate solar power

Everything starts when your solar panels create power. They do that by using their solar cells to capture the sun’s radiation and turn it into AC power. This AC power then needs to be transformed into DC power before it can be used in your home.

If you don’t have a solar battery, then this transformation will occur in the solar inverter. If you do have a battery, then it may or may not transform the energy from AC to DC power on its own with a built-in inverter.

2. Power that isn’t needed immediately gets sent to the solar battery

As your solar system generates solar energy, the power gets sent throughout your home depending on where it’s needed. But often, your solar panels will generate more power than you need to keep your things runnings.

When you have a solar battery installed, all of this excess energy gets sent to the battery. This charges the battery with energy, which can be used later in the same way that you typically use your solar panels to power your home.

3. The energy from the battery is used to power your home

Whenever your solar panels aren’t creating enough energy to satisfy your power needs, the extra energy will be drawn from your solar battery until all of its charge is gone. The solar battery may need to convert the power from AC to a usable DC form before this happens depending on what type of system you have.

How solar batteries store energy

Maybe you are also curious about the specifics of how solar batteries are able to store energy. If so, this section will answer that curiosity.

Most solar batteries today are made out of lithium-ion. These work by essentially sending lithium ions through the electrolytes that get transmitted to your solar battery from your solar panels. This process creates free electrons, which is the actual power that solar batteries store. These electrons can be drawn from the battery as needed to power your home.

Lithium-ion batteries accomplish this through a system of anodes and cathodes. These are what transmit the lithium ions throughout the battery so that they can create free electrons, which you can use to power your home.

How to store solar energy with batteries

For solar panel owners, getting started with storing solar energy through batteries is a straightforward, if expensive process. You begin by selecting the solar battery that you like best. Typically, this involves comparing the price of the battery to the amount of storage power it offers.

Once you have chosen your battery, you work with the manufacturer or an installer to get it added to your home’s solar system. This typically involves connecting the battery to some electrical wiring in your home, so it’s important that you let a trained professional do this unless you already are very familiar with the process yourself.

After that, your job is essentially done. Your battery will automatically begin charging when your panels produce excess power. And that stored energy will be the first thing used when you need more energy than your solar panels are producing at a given point in time.

What types of solar batteries are there?

There are four major types of solar batteries. These are distinguishable by the material that they are made from, which is also often referred to as the “chemistry” of the battery. Here’s an overview of each type of solar battery that you can choose from.


Lithium-ion batteries are the most common type of solar battery. They offer excellent efficiency and are still being improved upon to provide solar system owners with even better results. Some of the biggest batteries on the market, such as Tesla’s Powerwall, are made out of lithium-ion.


Lead-acid batteries used to be very popular in the early days of the home solar revolution. They are still quite dependable but they have fallen out of favor as options like lithium-ion become more dependable, more efficient, and more affordable.


Flow batteries are a relative newcomer to the solar battery market. They feature a water-based solution of zinc-bromide that flows between two tanks.

The main advantage that these batteries have is that they offer 100% depth-of-discharge, whereas lithium-ion batteries only tend to offer 80-90%. However, there are relatively few manufacturers making flow batteries at this time.

Sodium Nickel Chloride

Sodium nickel chloride batteries are another alternative to lithium-ion that some homeowners may want to consider. These batteries are able to operate at a wide range of temperatures, which could make them a good fit for homeowners that live in areas with extreme weather.

Additionally, sodium nickel chloride batteries are fully recyclable, have no fire risk, and require no internal cooling systems. The downside is that these solar batteries tend not to last as long as their lithium-ion counterparts.

Advantages of storing solar energy with a solar battery

There are lots of advantages to adding a solar battery to your system. We have a page that covers all of these benefits in more detail, but here are some of the highlights for you to consider:

  • Reduce your electricity bills
  • Improve your energy independence
  • Get the most out of the power that your solar system generates
  • Reduce your home’s carbon footprint
  • Enables you to take your home off the grid

Alternatives to solar batteries

If you don’t want to invest in a solar battery, then there are two main things that can happen. The first option is to allow the excess solar energy that your home generates to go to waste.

This isn’t ideal because it significantly limits the benefits that you’re able to get out of your system. By allowing excess energy to go to waste, you also reduce your cost-saving potential.

The second option is to take advantage of an electricity utility billing practice called net metering. The availability of net metering and the specific type that is available to you will vary by your location.

But the general idea is that, if you enroll in net metering, the excess power that your panels generate will be sent back into the electrical grid. You then get a credit for that electricity, which reduces your energy bill by a percentage that’s determined by your utility company.

Net metering is similar to using a solar battery in that it also enables you to take advantage of the excess power that your solar system generates. However, it forces you to rely on the electrical grid more than you would have to with a solar battery. Your savings on your electricity bill may also not be as high as they could be if you were using a solar battery to store that extra energy instead.

What solar batteries could be like in the future

Solar battery technology is rapidly improving as it becomes increasingly clear just how pivotal of a role solar batteries will play in the long-term adoption of solar power. This quickening rate of innovation suggests that the way we purchase and interact with solar batteries will change over the next decade.

As the technology gets better, we should see new batteries rolling out with more storage capacity, more efficiency, and lower prices. Eventually, we will reach a point at which not purchasing a solar battery simply doesn’t make sense from a financial perspective.

With that in mind, it is likely that we will see manufacturers shift to a model of including solar batteries in their standard solar energy systems instead of selling them separately. This will likely raise the cost of solar systems but will also make them much more effective at reducing energy bills and ending reliance on fuel-generated electricity.

A final word on how solar batteries work

Solar batteries are an extremely effective way to start getting more out of an existing solar energy system. They’re able to store the excess power that your panels generate so that you can use it whenever you need it.

Net metering is a viable alternative to a solar battery, but it likely won’t provide you with as great of savings as a battery and it doesn’t offer much for homeowners who would like to secure energy independence.

Matt Hope
Last Reviewed By: Matt Hope
Published: 2022-05-25