solar batteries buyer’s guide

Many solar batteries are available – how do you know which one suits you best? When selecting a solar battery, you should consider important aspects such as cost, capacity, power, round-trip efficiency, degradation rate, and warranty. Each solar battery’s quality rating takes into account all of these aspects and more.

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How solar batteries work

A solar battery’s primary function is to store energy produced by solar panels for later use. Storing energy for later use offers numerous benefits, ranging from financial advantages to serving as a backup power source during a grid outage.

One of the main advantages of installing a solar plus storage energy system is that it enables users to utilize solar electricity even when the sun isn’t shining. Without a battery, excess electricity generated by the system is typically sent back to the grid. However, with a solar battery, users can store this energy and use it when sunlight is not available. This means that users will only need to draw and pay for energy from the grid when their battery is depleted.

To gain more insight into the functioning of solar batteries, explore our section on solar battery systems.

How to compare solar batteries

There are many ways to compare solar batteries. Here are a few key metrics to keep in mind:

Capacity & power

The capacity of a battery refers to the total amount of electricity it can store, measured in kilowatt-hours (kWh). The power of a battery indicates the amount of electricity it can deliver at one point in time, measured in kilowatts (kW). When evaluating solar batteries, it’s important to consider both capacity and power. A battery with high capacity but low power can only deliver a small amount of electricity at one time but can store enough energy to continue providing that electricity for long periods. Conversely, a battery with low capacity but high power may have the ability to power many appliances or an entire home at one time, but possibly only for a few hours due to its low capacity.

Round-trip efficiency

Just like solar panels, solar batteries possess efficiencies. The round-trip efficiency of a battery signifies the percentage of energy that can be utilized compared to the energy expended in its initial storage. Batteries undergo efficiency losses of around 5 percent during the conversion of stored energy into usable electricity.

Battery life and warranty

Solar batteries naturally degrade over time like cell phone batteries, and their overall charge-holding capacity diminishes with increased usage. Typically, manufacturers measure solar battery warranties in cycles or years and assure a certain level of charge-holding capacity by the end of the specified warranty term.

Cost of solar batteries

Adding a solar battery to a solar panel system can pose challenges. This is because the savings associated with solar batteries rely on various factors such as your electricity rate structure and the amount of sunlight received. In numerous locations, individuals have the option to store surplus energy in the grid and receive credits on their electric bills. Solar batteries find their greatest utility in regions lacking such programs or where they are excessively complex. Additionally, they prove advantageous in areas characterized by fluctuating electricity prices. For instance, if electricity is more expensive during specific times of the day, a solar battery can enable you to economize.