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How long will a home battery storage system last?

Today, residential energy storage systems are gaining popularity among residential solar users. About 40 percent of Americans are concerned about frequent power outages, according to a recent survey of more than 1,500 U.S. households by solar developers. Of those who have already installed solar, 70% said they planned to install a battery storage system, with a majority expressing concerns about battery life. But it turns out that there are many factors that affect the life of a residential battery storage system.

In addition to providing backup power during outages, many battery storage systems intelligently schedule the import and export of electricity, designed to maximize the value of residential solar power systems. Some battery storage systems have been optimized for integration into EV charging facilities.

While the installed capacity of energy storage systems deployed is steadily climbing, deployment rates remain low. According to data released by Lawrence Berkeley National Laboratory (LBL), by 2020, 8.1% of residential solar systems in the United States will be equipped with battery storage systems.

There are many options for residential battery storage systems. But in the U.S., two companies dominate the residential battery storage space. According to Lawrence Berkeley National Laboratory (LBL), LG Chem and Tesla account for more than 90% of the U.S. residential energy storage market, with Teslas share exceeding 60%.

Tesla PowerWall battery energy storage systems come with a limited warranty claiming to be free from defects for 10 years after installation. It also guaranteed the PowerWall battery energy storage system an initial capacity of 13.5kWh and will guarantee its storage capacity according to a degradation schedule.

LG Chem said its energy storage system will maintain more than 60 percent of its storage capacity (9.8 kWh) for 10 years. Batteries must operate between -10C and 45C to maintain warranty coverage.

Residential solar installer Sunrun says batteries typically last between five and 15 years. This means that the battery storage system may need to be replaced during the 20 to 30-year lifetime of the solar facility.


Battery life is mainly determined by the life cycle. As evidenced by product warranties from LG Chem and Tesla, reaching the 60% or 70% capacity threshold within a certain charge cycle is guaranteed.


According to the Faraday Institute, there are two types of battery degradation: overcharging and trickle charging. Overcharging is the act of injecting current into a battery to fully charge it. Doing so can cause the battery to overheat and possibly catch fire.


Trickle charging refers to the process of continuously charging the battery to 100%. During this process, the battery capacity will inevitably be lost, and this process will increase the internal temperature, which will reduce the capacity and life.


Another cause of battery degradation over time, the Faraday Institute notes, is the loss of lithium ions from the battery's electrolyte. Side effects in the battery trap available free lithium, gradually reducing capacity.


While low temperatures can stop Li-ion batteries from functioning, they don't actually degrade the battery's performance or shorten its lifespan. Overall battery life is reduced at high temperatures, according to the Faraday Institute. This is because the electrolyte between the electrodes decomposes at high temperatures, causing the battery to lose its ability to flow lithium ions. This reduces the amount of lithium ions the electrode can accept into its structure, draining the lithium-ion battery's capacity.


maintenance matters


The National Renewable Energy Laboratory (NREL) recommends that home users install batteries in a cool, dry location, preferably a garage, to minimize the impact of a fire. The battery and its surrounding components should be properly insulated for cooling, and regular maintenance checks help ensure optimal operation.


The US National Renewable Energy Laboratory (NREL) stated that repeated deep discharges should be avoided as much as possible, because the more discharges, the shorter the life. If your residential battery storage system discharges a lot each day, it's time to add a battery pack.


The batteries connected in series should maintain the same charge, although the battery pack may display a total charge of 24V, there may be a voltage difference between the batteries, which is not conducive to protecting the long-term operation of the battery energy storage system. Also, it is recommended that the correct voltage set point for the charger and charge controller be set at the discretion of the battery manufacturer.


The National Renewable Energy Laboratory (NREL) says operators should check frequently. Things to check for include leaks (buildup outside the battery) and consistent voltage.