With battery storage becoming a larger component of residential solar systems, how long those batteries last is a key financial component of the decision-making process. According to Lawrence Berkley National Laboratory attachment rates for batteries more than doubled between 2020 and 2022 increasing from 8.1% to over 17%.
Two factors will continue to fuel this upward trend. Financial incentives are increasing. Second, net-metering rates are declining. Â This is making it less attractive to export energy to the grid and more likely battery storage will be used to further lower utility costs.
So when can consumers expect to have to replace their batteries?
Battery life is primarily driven by usage cycles. Proper installation, care, and maintenance also play a factor. Although cold temperatures can impact battery performance, it doesn’t impact its lifespan. The National Renewable Energy Laboratory recommends installing batteries in cool, dry places, and properly spacing out components.
Batteries connected in series should be kept at an equal charge. Another factor is to ensure voltage set points for chargers and charge controllers are correct. The point is that with battery storage, there is some work to do to maximize their lifespan.
From a usage standpoint you want to avoid overcharging your battery. And NREL also recommends whenever possible, avoid repeated deep discharging.
With all that said, how long should batteries last? Estimates and warranties range widely. Leading supplier Enphase warranties its IQ Battery for 10 years or 7,300 cycles. Sunrun estimates battery life between 5 and 15 years. Â And the LG and Tesla warranties thresholds of 60 to 70% capacity for a certain number of charge cycles.Â
In other words – make sure you read the fine print before selecting a vendor.