They're particularly useful for households that have time-of-use (TOU) energy plans or have electricity rates that are based on peak times, such as evenings and mornings.

The cost of a solar battery installation depends on a number of factors, including the size and type of the battery system, the labor required to install it and the state and federal incentives available for the installation. A popular battery-plus-inverter system that combines solar panels and batteries costs around $28,080 without the federal Clean Energy Credit, which gives homeowners up to 30% off their solar-plusstorage system.

Adding a solar battery to your existing system will increase your installation cost by about $1,000, depending on the capacity of your solar panel system and the number of batteries you have installed. It's best to contact a local solar company to have them assess your home and install the appropriate system for your needs.

Batteries are made of lithium-ion or lead-acid and come in a variety of sizes, capacities and price points. They usually last about 15 years. However, the lifespan of a solar battery will depend on how it's maintained. If you want to make your solar battery last longer, you can invest in a quality battery maintenance plan.

Battery chemistry and manufacturer: Lithium-ion is typically the most cost-effective battery material for residential applications. Although it isn't as powerful as leadacid, it can hold more energy than other battery types.

Brand: The brand you choose will impact the overall cost of a solar battery installation. Some brands offer better warranties than others. Other brands may provide more technical features, such as a built-in inverter, that can help your battery last longer.

Inverter: Most battery systems use an inverter to convert DC energy stored in the battery to alternating current electricity for your appliances and other devices. Most inverters are priced at about $1,500 to $3,000.

Smart technology: Some batteries have advanced technological features that can enhance their performance and durability. These can include an integrated inverter, an advanced monitoring system, and a battery charge controller that tracks the health of your battery.

Battery location: A battery is best positioned out of direct sunlight, in an indoor space such as a garage or basement, but some homeowners prefer to have it located on the roof to take advantage of rooftop solar. This location is important to prevent damage to the battery from extreme weather or other circumstances, such as a fire or hurricane.

A solar battery is a worthwhile investment, but the upfront costs of installing one can be high. This is especially true if you don't qualify for the 30% federal tax credit.

The savings you'll get from storing energy generated by your solar panels can offset the cost of a battery installation. The 30 percent federal tax credit for solar batteries isn't available for installations after 2033, so you should consider a storage system sooner rather than later if you want to maximize your investment.