Product Description

$250 Off Orders Over $5,000
BigBattery and EG4 orders of $5,000 or more qualify for $250 off, applied automatically at checkout. No discount code required.

An all-EG4 indoor energy storage system: the FlexBOSS18 hybrid inverter (18 kW PV / 13 kW AC, split-phase, 3 MPPT) paired with the EG4 WallMount Indoor battery — 48V 314Ah (16 kWh) per unit, UL9540A-tested with self-heating for reliable cold-weather charging. Configure one to three batteries for 16, 32, or 48 kWh.

What's in the kit

  • 1 × EG4 FlexBOSS18 hybrid solar inverter (18 kW PV / 13 kW AC, split-phase, 3 MPPT)
  • Your choice of 1, 2, or 3 × EG4 WallMount Indoor 48V 314Ah batteries (16 kWh each, UL9540A, self-heating)

Key features

  • UL9540A-tested battery design for garage, basement, and utility-room installations.
  • Self-heating cells keep charging available in cold spaces.
  • Single-brand ecosystem: EG4 inverter and EG4 batteries communicate natively for closed-loop operation.
  • Split-phase 120/240V output with remote Wi-Fi monitoring.

Good to know

Select your capacity from the Battery Configuration menu — pricing is for the complete kit. Ships by freight carrier; delivery timing is confirmed once your order is accepted. Professional installation by a licensed electrician is recommended, and local permitting requirements apply to home energy storage installations.

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