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BigBattery FETHS-48051-G1-06-Flex21K-02

30.7 kWh · 27.6–32 kW · Lithium Iron Phosphate · direct PV input · 2 configurations

UL 9540UL 1741 SBCEC listed · Apr 13, 2026
  • Nameplate energy30.7 kWh
  • Continuous power27.6–32 kW
  • ChemistryLithium Iron Phosphate

Overview

CEC Energy Storage System List

FETHS-48051-G1-06-Flex21K-02: 30.7 kWh nameplate energy; 27.6–32 kW continuous; lithium iron phosphate; accepts solar panels directly (DC-coupled).

Models & configurations

CEC Energy Storage System List · 2 listings
ModelEnergyPowerGrid voltageRound tripCEC listed
FETHS-48051-G1-06-Flex21K-02 {208V}30.7 kWh27.6 kW208 V—Apr 13, 2026
FETHS-48051-G1-06-Flex21K-02 {240V}30.7 kWh32 kW240 V—Apr 13, 2026

Capacity & power

CEC Energy Storage System List

Charging from solar in Southern California

NLR PVWatts v8 · Cali-Graf calculation · CEC Energy Storage System List
CityDecemberJune
Los Angeles9.6 kW5.7 kW
Palmdale8.8 kW5.2 kW
Chula Vista8.2 kW5.9 kW
Huntington Beach9 kW6.2 kW
Riverside9.2 kW5.4 kW
Santa Clarita9.1 kW5.4 kW
Solar array size that refills the battery from empty in one average day, before the home uses any of it (NLR PVWatts v8, 20° south roof).

Safety listings

CEC Energy Storage System List
UL 9540 certifies the whole storage system; UL 9540A is the fire-propagation test that fire codes ask for indoors and near walls.

California grid & code compliance

CEC Energy Storage System List

Compare with similar batteries

CEC Energy Storage System List
BatteryEnergyContinuous powerChemistryWarrantySoCal permits
EG4 Electronics PP-100A15-18K1-LL25.6 kWh10.4–12 kWLithium Iron Phosphate10 years—
EG4 Electronics PP-100A15-18K1-LP25.6 kWh10.4–12 kWLithium Iron Phosphate10 years—
EG4 Electronics PP-16/280A2-18K1-AWLL28.6 kWh10.4–12 kWLithium Iron Phosphate10 years—
EG4 Electronics PP-16/280A2-18K2-AWLL28.7 kWh20.8–24 kWLithium Iron Phosphate10 years—
EG4 Electronics PP-100A16-18K1-LP30.7 kWh10.4–12 kWLithium Iron Phosphate10 years—
EG4 Electronics PP-100A16-18K1-LL30.7 kWh10.4–12 kWLithium Iron Phosphate10 years—
Same segment, similar capacity; each row from the same sources.

Questions & answers

How much energy does the BigBattery FETHS-48051-G1-06-Flex21K-02 store?

30.7 kWh nameplate, per the California Energy Commission list.

Is the FETHS-48051-G1-06-Flex21K-02 UL 9540 certified?

Yes — the CEC list shows UL 9540 certification (certified by intertek).

Sources

  1. California Energy Commission — Energy Storage System List, data as of Oct 7, 2026. Manufacturer-reported values confirmed by CEC against certificates.
  2. NLR (formerly NREL) — PVWatts v8, NSRDB PSM v3 typical-year weather for Los Angeles, Palmdale, Riverside, Santa Clarita, Chula Vista, Huntington Beach.
  3. Cali-Graf calculations — formulas and inputs are shown next to each calculated value (efficiency from area, temperature-corrected voltages, string sizing, energy estimates).