How long does a home energy storage system last?

 

With the increasing popularity of residential solar energy, the deployment of complementary residential energy storage systems has become a major option for homeowners. A recent survey of more than 1,500 households by solar developer SunPower found that about 40 percent of Americans worry about frequent power outages. Among respondents who are actively considering installing residential solar power facilities, 70% said they plan to deploy battery storage systems.

 

In addition to providing backup power in the event of a power outage, the battery storage system incorporates technology that intelligently schedules energy imports and exports, with the primary goal of maximizing the value of residential solar systems. In addition, some battery energy storage systems are optimized to charge electric vehicles.

 

The SunPower survey reports that more and more consumers are showing interest in deploying energy storage systems to provide self-sustaining solar power. Nearly 40% of consumers cited self-sufficiency in electricity as the main reason for supporting the deployment of battery storage systems, up from less than 20% in 2022. Providing backup power and saving on electricity bills were also cited as the main reasons to support the deployment of battery energy storage systems. Deploy an energy storage system.

 

According to data released by Lawrence Berkeley National Laboratory, the deployment rate of battery storage system packages in residential solar projects is steadily climbing, from 8.1 percent in 2020 to more than 17 percent in 2022.

 

The warranty period provides insight into the expected operational lifespan of battery storage systems, as indicated by installers and manufacturers. Typically, the standard warranty period is around 10 years. For instance, the Enphase IQ battery comes with a 10-year warranty or 7,300 charge/discharge cycles.

Solar developer Sunrun states that batteries typically last between five to 15 years. This suggests that a replacement of the battery storage system may be necessary once within the 20-30 year lifetime of a solar power facility.

Battery longevity is primarily determined by charge/discharge cycles. LG and Tesla's product warranties demonstrate that they guarantee 60% or 70% capacity threshold after a specific number of charge/discharge cycles.

According to the Faraday Institute, two factors can lead to degradation in battery performance: overcharging and trickle charging. Overcharging can result in overheating and potential fire hazards, while trickle charging continuously brings the battery to full capacity leading to reduced overall capacity and lifespan due to increased internal temperature.

Another factor contributing to battery degradation over time is the loss of lithium ions in the battery electrolyte. Side reactions trap available lithium which gradually reduces overall capacity.

Faraday also notes that low temperatures may hinder effective operation but do not necessarily shorten effective life span; however, high temperatures can significantly reduce overall lifespan due to breakdown of electrolytes at high temperatures resulting in decreased lithium ion retention and subsequent depletion of lithium-ion battery capacity.

Battery maintenance

The National Renewable Energy Laboratory (NREL) recommends storing batteries in a cool, dry location, such as a garage, to minimize fire risk. Proper spacing for cooling of the battery and its surrounding components is essential, and regular maintenance checks are necessary to ensure optimal performance.

The laboratory advises against repeated deep discharge of the battery during use whenever possible, as this can shorten its service life. If a residential battery storage system is deeply discharging daily, it may be time to consider increasing the size of the battery pack.

According to NREL, a series-connected battery can retain charge; however, there may be voltage variations between multiple batteries even if they display 24V. This variation is not conducive to long-term protection of the battery storage system. It is also crucial to set the correct voltage set point for the charger and charge controller based on recommendations from the battery manufacturer.

NREL also recommends that operations personnel conduct frequent inspections for leaks (accumulation outside the battery), check fluid levels regularly, and ensure voltage consistency. While each battery manufacturer may have their own practices and experiences, referring to their maintenance guidelines and data sheets is considered best practice.