- This smart battery gives your DELTA Pro 3 power stations an extra 4096 Wh - great if you're camping or on a road trip - The EcoFlow app comes in very handy to monitor and control the battery using your smartphone - You've got surge protection to make sure your battery stays in tip-top shape ____________________________________________________________________________________________ Please note: The Smart Extra Battery cannot be used separately. It only increases the capacity of DELTA Pro 3 Portable Power Stations and can only be recharged by a DELTA Pro 3 or an EcoFlow Smart Generator.