How Does A Home Solar Power Battery Work?

Release time: Dec 22, 2023

An integral part of every solar power system is the solar battery. It expands your power alternatives and allows you to store excess electricity for usage when solar panels aren't producing enough.

If you're curious about the science behind solar batteries, how they function within a solar power system, and the many advantages of using solar battery storage, then this article is for you. It will also define solar batteries and explain how they work.

The Solar Battery: What Is It?

To begin, here is a basic explanation of what a solar battery is:

If your solar panels produce more electricity than you need, you can store it in a solar battery and use it later.

At times when your solar panels aren't producing enough electricity—during cloudy days, power outages, or nights—you can utilize that stored energy to power your home.

The primary objective of a solar battery is to maximize the utilization of the solar energy that you generate. In the absence of battery storage, all surplus power generated by solar panels is sent to the grid, meaning that you aren't making the most efficient use of the power your panels provide.

Solar Battery Research and Development

The solar battery market is dominated by lithium-ion cells at the moment. This is the same principle that powers modern electronic devices and cellphones.

The chemical process that powers lithium-ion batteries stores chemical energy for later use as electricity. The process starts when lithium ions give off their free electrons, which then go from the anode—which is negatively charged—to the cathode, which is positively charged.

The battery's lithium-salt electrolyte, a liquid that provides the positive ions needed to balance the reaction, promotes and enhances this movement. People can't use electricity without this flow of free electrons, which produces current.

Lithium ions return to the positive electrode of the battery when current is drawn from the battery. In the meanwhile, the plugged-in gadget gets its power from electrons flowing through the outside circuit from the negative to the positive electrode.

Solar power storage batteries for homes include a number of ion battery cells and complex electronics to control the system's operation and ensure its safety. In this way, solar batteries are similar to regular rechargeable batteries, except that they draw their power from the sun instead of traditional electricity sources.

Evaluation of Alternative Battery Storage Methods

Both lead-acid and lithium-ion solar batteries are popular choices. The solar panel industry favors lithium-ion batteries due to their superior energy storage capacity, longer duration of energy hold, and higher Depth of Discharge compared to other battery types.

Depth of Discharge, or DoD for short, is the ratio of a battery's usable capacity to its overall capacity. You can safely utilize up to 95% of a battery's capacity before it needs to be recharged if, for instance, the DoD is 95%.

Lithium-Ion Battery

As previously said, lithium-ion battery technology is the preferred choice of battery makers due to its higher degree of discharge (DoD), longer lifespan, increased energy storage capacity, and smaller size. While lithium-ion batteries have several advantages over lead-acid batteries, they are also more costly.

Lead-Acid Battery

In-home energy storage systems for off-grid power alternatives have long made use of lead-acid batteries, the same technology as most automobile batteries. Their low DoD and shorter lifespan are causing their popularity to fade, even though they are still available on the market at pocket-friendly rates.

AC vs. DC Coupled Storage

You can choose between direct current (DC) coupling and alternating current (AC) coupling when it comes to connecting your solar panels to your battery storage system. The direction that the solar-generated electricity travels is the key differentiator between the two.

In order for your home to use the electricity that solar cells generate, which is DC electricity, it must first be converted into AC electricity. Several methods exist for integrating solar batteries into solar power systems, however it's important to note that these batteries can only store direct current (DC) electricity.

DC Coupled Storage

Direct current (DC) coupling allows solar panels to send their generated DC power straight into a battery without first passing it through a charge controller. When the battery is ready to transfer power to your house or the grid, it converts DC current to AC current; otherwise, no current changes before storage.

Since the conversion from DC to AC only needs to happen once, a DC-coupled storage battery is more efficient. The installation of DC-coupled storage, on the other hand, is sometimes more complicated and time-consuming, which drives up the initial cost.

AC Coupled Storage

Through the process of AC coupling, the direct current (DC) power that your solar panels produce is first transformed into alternating current (AC) power that can be used by your household appliances. An other option is to use a separate inverter to transform the AC current into DC current, which can then be stored in the solar battery. The energy is transformed back into AC power for your home by means of an inverter when the time comes to use it, after having flowed out of the battery.

The three distinct steps of AC-coupled storage include inverting the electrical current three times: first, when it flows from your solar panels into your home; second, when it flows from your home into your battery storage; and third, when it flows back into your house from your battery storage. Storage that is AC coupled is marginally less efficient than DC coupled systems due to the efficiency losses that occur with each inversion.

An important benefit of AC coupled storage over DC-coupled storage is that it can store energy from both the grid and solar panels, which is not possible with DC-coupled storage. This allows you to take advantage of electricity rate arbitrage or have backup power in the event that your solar panels aren't producing enough power to completely charge your battery.

AC-coupled battery storage is a convenient way to update your current solar power system. Unlike integrated systems, it may be easily added to an existing design. This increases the appeal of AC linked battery storage for use in retrofits.

Battery Capacity

The capacity of a battery is the measure of its ability to store energy for subsequent usage. Kilowatt-hours are the usual units of measurement. The difference between the two is that usable capacity indicates the amount of energy that can be extracted from the battery. In order to function, solar batteries drain a portion of their stored energy, limiting their actual capacity.

The output of your solar panel system ought to be in sync with the capacity of your batteries. You will waste energy if you install a solar battery that is too tiny. Using one that's too big will result in a loss of useful storage space.

Discharge Depth

Maximize your storage capacity and boost energy savings with solar batteries that have a high depth of discharge (DoD). You lose some of the energy savings potential and end up wasting energy storage when you use a solar battery with a lower DoD. When compared to lithium-ion storage solutions, lead-acid batteries only provide 50% DoD.

Ratings of Power

Your battery's power rating is a measure of the amount of energy it can produce, measured in kilowatts. On a battery's label, you'll notice both the peak and continuous power ratings.

The maximum amount of power that a battery can generate in a single second is called its peak power. Smaller gadgets can be powered for longer by batteries with a lower power rating but a high capacity. A small battery with a high power rating can deliver a powerful surge of energy for a short period of time.

Powering a gadget for an extended period of time is indicated by the continuous power rating of a battery. The majority of batteries can provide 5 kW of continuous power. A stronger battery is indicated by a greater number. We assist homeowners in determining the finest battery solutions for running their houses more efficiently and for longer periods of time by focusing on continuous power ratings.

How Batteries Work with a Solar Power System

The process kicks off when the roof-mounted solar panels produce electricity. What follows is an explanation of how a DC-coupled system works:

1. Direct current (DC) electricity is generated when sunlight strikes solar panels.

2. The current flows into the battery and is stored there as direct current.

3. The third step is for the DC electricity to transfer from the battery to an inverter, where it will be transformed into AC electricity that can be utilized by the home.

An AC-coupled system requires a little different procedure.

1. Direct current (DC) electricity is generated when sunlight strikes solar panels.

2. The power goes into the inverter, which changes it into AC power that the house can utilize.

3. Afterwards, the surplus power is converted back into DC electricity by means of an additional converter, which allows for its storage for future use.

4. Fourth, the inverter must be used again to transform DC power into AC power whenever the home needs to draw on the energy stored in the batteries.

How Solar Batteries Work with a Hybrid Inverter

A hybrid inverter combines the capabilities of two devices into one, allowing it to transform DC power into AC power and vice versa. Consequently, your photovoltaic (PV) system can function with a single inverter instead of requiring a separate device to convert power from the solar panels to a form usable by your batteries.


The hybrid inverter integrates a solar inverter and a battery inverter into one unit; it is sometimes called a battery-based inverter or a hybrid grid-tied inverter. Because it can convert power from both your solar panels and your batteries, it's a great alternative to using two inverters in one system.

Because they may function with or without battery storage, hybrid inverters are becoming more popular. To make future additions of solar energy storage possible, a hybrid inverter can be integrated into a battery-less solar power system during the initial installation.

Advantages of Solar Battery Storage

Improving your solar power system's efficiency is as simple as installing a battery backup system for your panels. A solar battery storage system for the house has many advantages, the most important of which are:

Converts Overage Power into Usable Energy

During the day, when no one is home to use the electricity, your solar panels might generate more power than you consume. Without a way to store excess solar power, it will be fed back into the grid. While participating in a net metering program can allow you to gain credit for excess generation, the ratio of credit to actual electricity generated is typically not 1:1.

Instead of sending the excess power to the grid, battery storage allows you to save it for later use. By drawing on the stored energy when generation is low, you can lessen your load on the power system.

Offers Protection During Power Outages

You won't have to worry about running out of power when the grid is down or when your solar panels produce more energy than you need because your batteries can store the extra energy.

Minimizes the Environmental Impact

One way to reduce your environmental impact is to use solar panel battery storage to store the clean energy that your panels generate. In the absence of energy storage, you will be forced to depend on the grid in the event that your solar panels fail to provide a enough amount of power. On the other hand, most grid electricity comes from fossil fuels, so it's safe to say that you'll be utilizing filthy energy if you draw from the grid.

Supply Power Long After the Sun Has Dipped Below the Horizon

In the absence of battery storage, the grid steps in to supply much-needed power when the sun goes down and solar panels stop generating electricity. Using a solar battery allows you to draw more power from the sun during the night, allowing you to reduce your power bill and increase your energy independence.

A Quiet Solution to Backup Power Needs

One alternative for silent backup power storage is a solar power battery. Instead of dealing with the noise that a gas-powered backup generator makes, you may enjoy clean energy that doesn't require maintenance.


If you're considering integrating solar panels with energy storage, it's crucial to have a good grasp of how a solar battery operates. Your solar panels will produce more energy than you need, but you will have more control over when and how you use it thanks to this system, which functions like a big rechargeable battery for your house.

By storing energy through a chemical reaction and then releasing it as electrical energy for use in your house, lithium-ion batteries—the most common kind of solar battery—function. You can lessen your load on the grid and perhaps boost your solar power system's return on investment by going for a DC-coupled, AC-coupled, or hybrid system.


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