Do Solar Panels Store Energy? If so, how?

Each day, we know that energy, electricity, and power generated by the sun will slowly set on the horizon leading to yet another cold and dark night. We cannot generate that power at night, but rest assured the sun will come up again the next day, and this time, you can store the excess energy it creates in a solar battery.

Solar panels alone can not store energy, but solar batteries can become part of your solar system and story energy for use at night, during cloudy weather, or as a temporary fix for a power outage. Batteries are charged in the day time with excess electricity not used in your home.

It is important to be able to store that energy for future use. The power that a battery is able to generate through your solar panels and the sunlight can last for up to 15 years, leaving you with a bank of power ready for any emergency you may face. Having a battery also opens up opportunities to help others on the power grid.

How Do Solar Batteries Work

Step by step, there is a process to which solar batteries work. The first step is obviously the collection of sun and its conversion to energy. This is done through the photon movement in your solar panels. Once it collects that energy it will eventually be converted from DC power into AC power. Depending on the battery you choose, it will either store it in DC power straight from the panels, or convert it to AC and than store it that way.

On a bright sunny day, solar panels will generate enough energy to power your home and more. It will be powering your lights, your TV, your air conditioning and everything in between, yet it will still be producing excess power. Without a battery, this power is just given back to the power grid. This helps cut down you electricity bill because it gives your power meter a negative intake, and the power grid will usually give it to you as a credit to use at night and other times the solar panels are not generating your power.

On the other hand, if you have a battery, this excess energy is used to power and charge your battery to be used at other times instead of leaning back on the power company. Once your battery becomes fully charged, and all appliances and electricity in your home are functioning through its power, the excess energy will once again go back to the power company by using a system called net metering.

“How quickly the battery charges depends on the amount of extra energy being produced, which itself depends on multiple factors like the size of the solar system and the current electricity demand in the home” Source. Most 12 volt batteries will take anywhere from 5 to 8 hours to charge from your solar panels. Make sure that the amps are not overpowering the battery and charging it too quickly as this will reduce the life of the battery and its capacity to hold the power.

AC & DC Batteries

We have already mentioned AC and DC power and batteries. There are a variety of differences between them and understanding them will help you as you choose which kind of battery you want and how it will work with your system.

DC stands for direct current, and it is the type of power that is first created from the energy and the solar panels. It is also what charges batteries. All batteries are charged with DC power. DC uses electrons that travel in a straight line, it uses linear movement rather than a wave motion like AC power does.

AC stands for alternating current. With AC power electrons move in a way changing back and forth from positive to negative charge. This is the standard power that comes out of the outlets in your home. AC has an advantage over DC power because it travels in waves, and can therefore travel farther than DC power. AC power is used to power many electrical appliances.

Every time power is converted from DC or AC or from AC to DC there is a power loss of about 5% because of the heat that is generated. Some solar batteries, though using DC power, are called AC batteries. “An AC battery is one that can accept incoming AC power, and it uses a built-in inverter to convert that to DC power, which then charges the battery. When the battery dispenses power to the home, the inverter then converts the DC power coming from the battery pack back into AC, which then feeds into the home” Source.

After the battery is charged, it is there to help feed the power in your home anytime you need it.

Getting & Giving Energy From the Grid – Net Metering

“Net metering is a billing mechanism that credits solar energy system owners for the electricity they add to the grid” source. In more simple terms it follows this process: “the homeowner is only billed for the “net” energy used each month, that is, the difference between the energy produced by the solar power system and the energy consumed by the house over the monthly billing period” source. Being able to generate power in excess of what you need is incredibly helpful to not only you but to those around you and to the power grid in general. It lessens your electricity bill and allows you to credit the power grid in case you need to use the power from the grid in an emergency.

It also has other benefits for the community and world. “Net metering increases demand for solar energy, which in turn creates jobs for the installers, electricians, and manufacturers who work in the solar supply chain. Today, the solar industry employs more than 250,000 American workers in large part due to strong state net metering policies which have allowed the solar industry to thrive” Source.

In different states throughout the US there are varying policies and regulation on Net Metering and it is a hot topic in the world. Policies are constantly being changed and updated. The more people who go solar, the more such policies will change, therefore changing some of the benefits of solar energy.

Cost of Solar Batteries

Solar batteries, as we have discussed will be a great addition to your solar system. They will help you to be less dependent upon the power grid and allow you to be energy efficient as you save and store power for future use. Often times solar batteries are not cheap, but the cost will depend upon the materials and type of battery you choose. As you consider the costs of the battery itself, it is also important to know that there will be additional costs for an inverter, other needed wiring, and installation.

Generally a solar battery will cost anywhere from $6,000 to $12,000 dollars. Sometimes that will include installation, other times it will add to the overall cost. There are a variety of things you should look into as you consider different batteries.

Power & Capacity

Each battery on the market will be able to tell you how much power it will actually store, its capacity. This is important because you will need to know how long a battery would last if you needed to use the power it holds. They will also display the power rating, which tells you how much power it can give your home at a given time. These go back and forth, here is an example: “Batteries with a high capacity and a low power rating are useful as emergency backup generators, as they can power a few important appliances, like a refrigerator or a washing machine, for a prolonged period of time. A battery with a low capacity and a high power rating will be able to power the whole house, but only for a few hours because there is less electricity stored in the battery.”source.

Depth of Discharge & Round-Trip Efficiency

Two more considerations are the Depth of Discharge and the Round-Trip Efficiency. DOD (Depth of Discharge) “is the percentage that a battery has been discharged relative to the total capacity of the battery” source. The Round Trip Efficiency is “the amount of energy you can use from your solar battery compared to the amount of energy it took to store that energy” source. Higher Efficiency batteries will end up saving you money because they will last longer and you will be able to use more of the energy. A higher DOD will also be helpful to you because you will not have to charge the battery as often because it will use up its power.


In the end, having a solar system is great, but having it in conjunction with a solar battery will help you in the long run. It can help you become involved in Net Metering and will help to power your home at night. It may even end up helping your neighbors too, so check out the costs and find the best battery for you.

Recent Posts