What is a Solar Battery? Benefits, Types & How to Choose

In this article, you will learn about what a solar battery is, the benefits of using one, the different types available, and the key factors to consider when choosing the right solar battery for your needs.

What is a Solar Battery?

As a solar rooftop owner, you may not use the solar energy at the exact time it is produced. That is the main reason solar batteries exist. The reasons may vary from climate and geography to culture and lifestyle.

For example, according to the U.S. Energy Information Administration, peak power usage often occurs on summer evenings, when solar energy generation is at its lowest. Conversely, for households where people work during the day, the highest energy consumption is likely to take place in the evenings.

All these differences between energy production and consumption create a need for storage technology. In short, solar batteries store surplus energy generated by solar panels. This means you can use the extra energy to power your house on cloudy or rainy days, or after the sun goes down – i.e., when energy production is low.

What are the Benefits of Using a Solar Battery?

• Maximize Solar Energy: You get the most out of the solar energy generated by your rooftop system. Wasting surplus energy would contradict the initial motivation to protect the planet and use resources wisely.
• Energy Independence: If your rooftop solar system and battery are large enough, you can run your home mostly on solar power.
• Cost Savings: Using electricity from your battery can be cheaper per kilowatt-hour than using electricity from the utility grid, depending on the time of day and electricity tariffs. Solar storage also eliminates the risk of rising electricity prices.
• Grid Stability: Solar batteries can help ease variations in solar energy flows caused by changes in sunlight.

What are the Types of Solar Batteries?

There are four main types of batteries used to store solar energy — lead-acid, lithium-ion, flow batteries, and nickel cadmium.

Segmentation Based on Timeframe

Short-term storage: Completed in minutes to ensure the system works despite passing clouds.

Long-term storage: Provides supply over days or weeks, useful when production decreases due to significant climate changes.

Things to Look Into When Choosing a Solar Battery

When choosing a solar battery, consider your personal needs such as geography, climate, energy production system, energy consumption habits, and budget.

For example, if energy generation is highest in the afternoon but consumption peaks at night, a storage system is beneficial. A 5kW solar system typically requires a battery capacity of 10-13kWh.

Technical Features of Solar Batteries

• Battery Size (kWh): Measured in kilowatt-hours. Determines how long your battery can power appliances. For example, a 10kWh battery lasts 10-12 hours with 0.75-1 kW hourly consumption.
• Energy Capacity (kW): Measured in kilowatts. Refers to the rate of electricity usage. Most batteries have a continuous power output of around 5 kW.
• Round-trip Efficiency: The percentage of electricity put into storage that is used later. Higher efficiency means less energy loss (typically ~80%).
• Depth of Discharge (DoD): The amount of energy you can actually use. E.g., an 8kWh battery with 80% DoD offers 6.4 kWh usable energy.
• Battery Lifetime: Measured in expected years, throughput, or cycles. Solar batteries have high lifecycles and don't require frequent replacement.
• Safety: Ensure the battery meets all safety requirements for installation in homes and businesses.