Equipment › Batteries › StackRack Battery Systems › SRxK-ULBattery module StackRack Battery Systems
StackRack Battery Systems SRxK-UL 5.1 kWh · 2.56 kW · Lithium Iron Phosphate
UL 1973 CEC listed · Mar 1, 2023
Nameplate energy 5.1 kWh Continuous power 2.56 kW Warranty 10 years Chemistry Lithium Iron Phosphate Compare ≈ 5.1 h of backup at a 1 kW average load Facts checked Oct 14, 2026 · sources at the bottom
Capacity Solar Inverter Installation Warranty Safety Specs Compare Q&A
Overview CEC Battery List SRxK-UL: 5.1 kWh nameplate energy; 2.56 kW continuous; lithium iron phosphate; 10 years warranty.
Capacity & power CEC Battery List Nameplate energy (CEC) 5.1 kWh Total energy (datasheet) 5.1 kWh Max continuous discharge (CEC) 2.56 kW Full-power discharge time about 2 h at full power Round-trip efficiency (datasheet) 95% Chemistry Lithium Iron Phosphate Battery voltage (DC, nominal) 51.2 V Battery voltage range (DC) 48–58 V
Charging from solar in Southern California 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).
Inverter & compatible equipment CEC Battery List Certified systems using this battery F1212, F1224, F1225
Installation & environment CEC Battery List · StackRack Battery Systems datasheet Operating temperature −10 to 50 °C Weight per kWh 1 kWh
Warranty CEC Battery List · StackRack Battery Systems datasheet Warranty term 10 years Warranted cycles 6,000 cycles
Safety listings CEC Battery List UL 1973 (stationary battery) Certified by TUV SUD Certificate date & edition Jan 4, 2023 · Ed. 2 : 2018 UL 9540A (fire propagation test) Yes Other standards on datasheet UL 9540A, UL 9540, UL 1973 UL 9540 certifies the whole storage system; UL 9540A is the fire-propagation test that fire codes ask for indoors and near walls.
Full specifications CEC Battery List · StackRack Battery Systems datasheet Communication rs485 Manufacturer website stackrackbattery.com
Compare with similar batteries CEC Energy Storage System List Same segment, similar capacity; each row from the same sources.
Questions & answers How much energy does the StackRack Battery Systems SRxK-UL store? 5.1 kWh nameplate, per the California Energy Commission list.
What warranty does the SRxK-UL have? 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. StackRack Battery Systems — manufacturer datasheet “SR5K-UL 100 AH 5.12 kWh”. 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).
