SimpliPHI 6.6 Battery 6.65kWh LFP 48V Stackable (by Briggs & Stratton)

The SimpliPHI 6.6 kWh LFP Battery 48 V by Briggs & Stratton delivers big-system performance in a modular, wire-free package. Each 6.65 kWh module snaps together with RapidStak™ connectors—no external cables, DIP switches or communication harnesses—to create indoor- or outdoor-rated banks that install in minutes and scale to whole-home capacity.

• 6.65 kWh usable capacity (130 Ah @ 51.2 V)¹
• 6.66 kW continuous / 8.3 kW 10-s surge per module¹
• 100 % depth-of-discharge; 4,500 cycles @ 100 % DoD or 6,000 cycles @ 80 % DoD (75 % end-of-life capacity)¹
• ≥96 % round-trip efficiency¹
• Stack up to 3 modules (19.95 kWh) and 6 stacks (119.7 kWh) per system¹
• RapidStak™ one-plug power data connector – stack of 3 installs in < 5 min²
• Operating range –4 °F – 131 °F (-20 °C – 55 °C) and IP65 when stacked¹
• CAN & RS-485 communications; Sol-Ark® and other major inverter partners¹
• Safety certifications: UL 9540 Ed 3 / UL 9540A, UL 1973, UN 38.3, IEC 62619¹
• 10-year / 6,000-cycle manufacturer warranty³

Scalable 6.65 kWh building block

Start with a single module for essential loads or stack up to three (19.95 kWh) on one ground or wall base. Six stacks network together for nearly 120 kWh of storage—enough for large homes or light-commercial sites without adding cabinets or conduits.

RapidStak™ wire-free installation

All power and communications ride through a rugged one-piece connector. Drop a battery into place, click, done—Briggs & Stratton timed a three-high stack at under five minutes. Installers spend less time on site and eliminate wiring errors.

Ultra-safe, cobalt-free LFP chemistry

Lithium Ferro Phosphate (LiFePO₄) cells offer superior thermal stability, no risk of thermal runaway and non-toxic materials. Combined with third-party safety listings, the SimpliPHI 6.6 is approved for indoor or outdoor placement—even in occupied spaces.

High power & efficiency

Each module can source or sink 6.66 kW continuously and up to 8.3 kW for motor-starting surges, while maintaining ≥96 % round-trip efficiency—ideal for heavy loads, off-grid autonomy or peak-shaving applications.

Engineered for decades of service

Expect 6,000 cycles at 80 % DoD—over 15 years of daily cycling—backed by a 10-year warranty and a 75 % end-of-life capacity guarantee.

Built to handle the elements

The powder-coated steel enclosure is IP20 as a single module and IP65 when stacked, with an operating window of -20 °C to 55 °C and corrosion resistance tested to 240 hours of salt-fog—no external cabinet required.

Size

28.6" W × 6.7" D × 18.9" H (one module)

Weight

140 lb

Frequently bought together:

• Briggs & Stratton (SimpliPHI) 6.6 Battery Controller
• Briggs & Stratton (SimpliPHI) 6.6 Wall Base
• Briggs & Stratton (SimpliPHI) 6.6 Floor Base
• SimpliPHI Briggs & Stratton EnergyTrak Gateway