Fortress Power LLC eFlex 5.4

The Fortress Power LLC eFlex 5.4 is a home battery from Fortress Power LLC. It stores 5 kWh in Lithium Iron Phosphate cells. Rated AC power 5.4 kW. Listed and verified: UL 1973 and UL 9540. Sold in United States.

Specifications

Capacity: 5 kWh
Battery chemistry: Lithium Iron Phosphate
Rated AC power: 5.4 kW

Product details

Product type: Home battery
Brand: Fortress Power LLC
Category: Home Battery Storage
Sold in: United States
Listed in: California Energy Commission

Models (1)

Model	Nominal capacity	Usable capacity	AC power	Certificate
eFlex 5.4	5 kWh		5.4 kVA

Certifications

Certification	Market	Status	Reference	Valid until
UL 1973	United States and Canada	✓ Verified 19 October 2026	Intertek
UL 9540	United States and Canada	✓ Verified 19 October 2026	Intertek

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