Expand your system's capabilities by increasing its capacity with the DELTA 3/DELTA 3 Plus Smart Extra Battery from EcoFlow. For existing owners of DELTA 3 and DELTA 3 Plus, this battery adds an additional 1024Wh of power capacity to your home. Internally, the power is provided by long-lasting LFP battery cells. The stackable design makes it easy to physically incorporate the new battery with your existing batteries and hookup is designed to be plug and play.