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Home battery systemFortress Power

Fortress Power Avalon-PRO-5P1-xxP2M5

49 kWh · 5 kW · Lithium Ion · direct PV input

UL 9540UL 1741 SBCEC listed · Mar 1, 2024
  • Nameplate energy49 kWh
  • Continuous power5 kW
  • Round trip (AC)93%
  • ChemistryLithium Ion

Overview

CEC Energy Storage System List

Avalon-PRO-5P1-xxP2M5: 49 kWh nameplate energy; 5 kW continuous; lithium ion; accepts solar panels directly (DC-coupled).

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 Angeles15.3 kW9 kW
Palmdale14.1 kW8.2 kW
Chula Vista13 kW9.3 kW
Huntington Beach14.4 kW10 kW
Riverside14.6 kW8.7 kW
Santa Clarita14.5 kW8.5 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
Sol-Ark L3 HVR36.9–55.3 kWh30–60 kWLithium Iron Phosphate10 years7
EG4 Electronics PP-16/280A3-18K1-AWLL43 kWh10.4–12 kWLithium Iron Phosphate10 years—
EG4 Electronics PP-16/280A3-18K2-AWLL43 kWh20.8–24 kWLithium Iron Phosphate10 years—
Power Center Duracell14–42 kWh5 kWLithium Iron Phosphate——
Sol-Ark L3 HV-xxKWH-xxK36.9–55.3 kWh30–60 kWLithium Iron Phosphate10 years—
Same segment, similar capacity; each row from the same sources.

Questions & answers

How much energy does the Fortress Power Avalon-PRO-5P1-xxP2M5 store?

49 kWh nameplate, per the California Energy Commission list.

Is the Avalon-PRO-5P1-xxP2M5 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).