Fox ESS S22 2.1 kWh Plug & Play Battery Expansion

The Fox ESS S22 is a compact all-in-one storage system for smaller residential solar installations. It combines an 800 W rated inverter and a LiFePO₄ battery with 2.11 kWh nominal energy (90% usable capacity) in one floor-mounted unit that measures 420×285×255 mm and weighs 26.5 kg for the S22-M-H variant. The manufacturer lists the S22 under its hybrid inverter range and describes it as compatible with its high-voltage batteries.

The unit delivers 800 W continuous output with a peak of 1.2 kVA, and an optional EPS output can keep key circuits running during a grid outage. The rated cycle life is more than 6,000 cycles at 90% depth of discharge. The operating temperature range is -20°C to 55°C, and the enclosure is rated IP65 for indoor or outdoor mounting. An optional integrated battery warming function is listed for cold-weather installations.

Monitoring is provided through the FoxCloud 2.0 portal and mobile app, with Wi-Fi, Bluetooth, LAN and RS485 interfaces and a built-in OLED display. Up to four units can be stacked for a total of 8.44 kWh.