Fortress Power FP-Nano-S8-I

Name: Fortress Power FP-Nano-S8-I
Brand: Fortress Power

41 kWh · 41 kW · Lithium Iron Phosphate

UL 1973CEC listed · May 21, 2026

Overview

CEC Battery List

FP-Nano-S8-I: 41 kWh nameplate energy; 41 kW continuous; lithium iron phosphate.

CEC Battery List

NLR PVWatts v8 · Cali-Graf calculation

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).

CEC Battery List

CEC Energy Storage System List

Battery	Energy	Continuous power	Chemistry	Warranty	SoCal permits
BYD BATTERY-BOX PREMIUM HVL (US)	12–32 kWh	7.5–20 kW	Lithium Iron Phosphate	10 years	1
Growatt APX HV Battery US	27 kWh	2.5–12 kW	Lithium Iron Phosphate	10 years	—
Tigo Energy GO Battery (US)	27 kWh	2.5–12 kW	Lithium Iron Phosphate	10 years	—
EG4 Electronics PP-16/280A2-18K2-AWLL	28.7 kWh	20.8–24 kW	Lithium Iron Phosphate	10 years	—
EG4 Electronics PP-100A16-18K1-LP	30.7 kWh	10.4–12 kW	Lithium Iron Phosphate	10 years	—
EG4 Electronics PP-100A16-18K1-LL	30.7 kWh	10.4–12 kW	Lithium Iron Phosphate	10 years	—

Same segment, similar capacity; each row from the same 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.
NLR (formerly NREL) — PVWatts v8, NSRDB PSM v3 typical-year weather for Los Angeles, Palmdale, Riverside, Santa Clarita, Chula Vista, Huntington Beach.
Cali-Graf calculations — formulas and inputs are shown next to each calculated value (efficiency from area, temperature-corrected voltages, string sizing, energy estimates).