Cali-Graf in Southern California

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104.5 kWh

Commercial batteryFortress Power

Fortress Power FP-Mega-S1-O

104.5 kWh · 52 kW · Lithium Ion

UL 1973CEC listed · Sep 11, 2026

Nameplate energy104.5 kWh
Continuous power52 kW
ChemistryLithium Ion

Overview

CEC Battery List

FP-Mega-S1-O: 104.5 kWh nameplate energy; 52 kW continuous; lithium ion.

Capacity & power

CEC Battery List

Nameplate energy (CEC)104.5 kWh
Max continuous discharge (CEC)52 kW
Full-power discharge timeabout 2 h at full power
ChemistryLithium Ion

Safety listings

CEC Battery List

UL 1973 (stationary battery)Certified by UL
Certificate date & editionDec 24, 2025 · Ed. 3 : 2022

Sources

California Energy Commission — Energy Storage System List, data as of Oct 7, 2026. Manufacturer-reported values confirmed by CEC against certificates.
California Energy Commission — Battery List, data as of Oct 7, 2026.