Abstract:This paper presents an experimental investigation in reusing vehicle traction lithium ion batteries for a second life application as a stationary energy storage system. A single family household demonstrated solar storage and demand side management, integrating a PV array, a grid interface and battery energy storage. The stationary battery pack, composed of retired vehicle traction batteries, serves as an energy buffer accumulating excess PV panel generated energy during off-peak hours and discharging during peak hours. A battery management system was developed to mitigate battery imbalance issues via extended Kalman filter SoC estimator, enhanced high current shunting, and protective circuitry. The day-ahead market pricing signal available from the California Independent System Operator was scrapped as the simulated market bidding signal. The system provided a proof of concept that retired EV batteries can be reused as distributed energy storage, and participate in demand response with dynamic pricing, benefiting both transportation and utility grid sectors.