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250.9–313.6 kWh

Commercial energy storage systemPylontech

Pylontech Optim US-B2-M5A180-A-ex/xxx.xx-US-05

250.9–313.6 kWh · 125.4–156.8 kW · Lithium Iron Phosphate · 3 configurations

UL 9540CEC listed · Jun 11, 2026

Nameplate energy250.9–313.6 kWh
Continuous power125.4–156.8 kW
ChemistryLithium Iron Phosphate

Overview

CEC Energy Storage System List

Optim US-B2-M5A180-A-ex/xxx.xx-US-05: 250.9–313.6 kWh nameplate energy; 125.4–156.8 kW continuous; lithium iron phosphate.

Models & configurations

CEC Energy Storage System List · 3 listings

Model	Energy	Power	Grid voltage	Round trip	CEC listed
Optim US-B2-M5A180-A-ex/250.88-US-05	250.9 kWh	125.44 kW	—	—	Jun 11, 2026
Optim US-B2-M5A180-A-ex/282.24-US-05	282.2 kWh	141.12 kW	—	—	Jun 11, 2026
Optim US-B2-M5A180-A-ex/313.6-US-05	313.6 kWh	156.8 kW	—	—	Jun 11, 2026

Capacity & power

CEC Energy Storage System List

Nameplate energy (CEC)250.9–313.6 kWh
Rated power (CEC)125.4–156.8 kW
Max continuous discharge (CEC)125.4–156.8 kW
Full-power discharge timeabout 2 h at full power
ChemistryLithium Iron Phosphate

Safety listings

CEC Energy Storage System List

UL 9540 (energy storage system)Certified by TUV Rheinland of North America
Certificate date & editionApr 7, 2024 · Ed. 3 : 2023

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

UL 1741 SB (IEEE 1547-2018)No
UL 1741 SA (Rule 21)No
CSIP (IEEE 2030.5)No
JA12 declaration (Title 24)No

Questions & answers

How much energy does the Pylontech Optim US-B2-M5A180-A-ex/xxx.xx-US-05 store?

250.9–313.6 kWh nameplate, per the California Energy Commission list.

Is the Optim US-B2-M5A180-A-ex/xxx.xx-US-05 UL 9540 certified?

Yes — the CEC list shows UL 9540 certification (certified by tuv rheinland of north america).

Sources

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