Finding the right battery for storing your solar energy can be a long process for those who have solar power or are looking into setting up a solar power system.

While batteries aren’t necessary for a solar power system connected to an energy grid, they are a great way to ensure that you never run out of power. For an off-grid system, though, batteries are an absolute necessity. 

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How Do Solar Batteries Work?

The term “solar battery” can make it seem like you’ll need a fancy, high-tech battery for your power system. While it is true that you’ll need a rather big battery, they aren’t all that different from a regular battery.

Just like regular batteries, solar batteries store power. They’re set up as a backup plan and can hold your excess solar energy for when your panels cannot produce enough energy.

Solar batteries charge by taking in excess energy that you don’t use. If you aren’t using the energy produced by your solar panels, it will first go into the battery. Once the battery is fully charged, the remaining energy will be returned to the power grid if you’re connecting to it.

With a fully charged battery, you’ll have access to power even when the sun isn’t out or if the local power grid goes down. If the power grid is still functioning and your battery gets low, it will recharge with energy from the power grid. 

This continues until your solar panels can produce enough energy to power your home once again.

How to Choose the Best Batteries

There’s a lot to keep in mind when you search for a solar battery. There are different types of batteries and many different brands, but there are a few easy ways to compare them all and some pointers to consider.

  1. Capacity

The amount of energy that a battery can hold is significant. The capacity of a solar battery is typically measured in kilowatt-hours (kWh), and the higher the number, the larger the capacity.

  1. Power

This is the amount of energy that your battery can provide and is generally measured by kilowatts (kW). A high-power battery is better for powering equipment with high electricity consumption.

It’s vital that both your capacity and power are high, or you may quickly run out of energy and not be able to power your larger devices.

  1. Depth of Discharge (DoD)

This is the percentage of the battery you can use. You should never use 100% of a battery’s charge and each manufacturer will specify the limit. Just like power and capacity, you want a battery with a higher DoD. This allows you to use more of your battery’s charge without damaging it or shortening its lifespan.

  1. Battery Life

A longer lifespan will mean you won’t have to replace your battery as often, so it’s essential to look at the battery’s life. Over time, your battery’s performance will decline, and as you approach the end of your battery’s lifespan, the performance will decrease even faster.

Battery Options

Now that you know what to keep in mind, it’s time to look at the different battery options available. Some battery types are better for a specific purpose than others, but all batteries work for storing solar energy.

Lead-Acid Batteries

Lead-acid batteries are typically used for off-grid systems and are relatively cheap. They have a high watt-hour capacity ratio and come in different forms. They do have a low lifespan and only a 60% DoD, but they’re an affordable backup option.

Lithium-Ion Batteries

These are by far the most popular battery choice. Although they are more expensive, they are long-lasting and have a higher DoD (80%-90%). They are powerful batteries and are easy to install.

Saltwater Batteries

Saltwater batteries are non-toxic and super safe. They can be completely drained of power and are recyclable. They do have a lower capacity and aren’t as powerful as lithium batteries, but there is much less risk of fire and do better in high-temperature areas.


Solar batteries are a great way to store backup energy and keep your solar power system running efficiently. The right battery will keep your energy system running so take the time to find the best one.