Cali-Graf in Southern California

For pros Sign in

176.4 kWh

Commercial energy storage systemFortress Power

Fortress Power Avalon-ESS-5P3-xxx.xP2M6

176.4 kWh · 15 kW · Lithium Ion · direct PV input

UL 9540UL 1741 SBCEC listed · Mar 1, 2024

Nameplate energy176.4 kWh
Continuous power15 kW
Round trip (AC)93%
ChemistryLithium Ion

Overview

CEC Energy Storage System List

Avalon-ESS-5P3-xxx.xP2M6: 176.4 kWh nameplate energy; 15 kW continuous; lithium ion; accepts solar panels directly (DC-coupled).

Capacity & power

CEC Energy Storage System List

Nameplate energy (CEC)176.4 kWh
Rated power (CEC)15 kW
Max continuous discharge (CEC)15 kW
Full-power discharge timeabout 11.1 h at full power
Round-trip efficiency (AC-AC)93%
ChemistryLithium Ion
Grid connection240 V

Safety listings

CEC Energy Storage System List

UL 9540 (energy storage system)Certified by Intertek
Certificate date & editionDec 13, 2023 · Ed. 2 : 2020

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)Yes
UL 1741 SA (Rule 21)Yes
CSIP (IEEE 2030.5)Yes (with conditions)
JA12 declaration (Title 24)Yes
JA12 control strategiesBasic, Advance DR
Last CEC updateMay 21, 2024
Monitor Key Data schedulingYes

Questions & answers

How much energy does the Fortress Power Avalon-ESS-5P3-xxx.xP2M6 store?

176.4 kWh nameplate, per the California Energy Commission list.

Is the Avalon-ESS-5P3-xxx.xP2M6 UL 9540 certified?

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

Sources

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