SMA SHP FLEX-US-21

Name: SMA SHP FLEX-US-21
Brand: SMA

String inverter. 10 models, 55 kW–172 kW AC at 208 V / 320 V / 380 V / 385 V / 400 V / 420 V / 480 V / 600 V / 630 V / 660 V.

UL 1741 SBCEC listed · Nov 1, 2024

Model

Rated AC power112.7 kW
CEC weighted efficiency98.5%

Models & power ratings

CEC Grid Support Inverter List (Oct 7, 2026) · NLR SAM inverter library · 10 models

Model	Nominal AC	Grid voltage	CEC continuous	Rated AC (SAM)	CEC weighted eff.	DC test window	CEC listed	UL 1741 SB
SHP FLEX-US-21	55 kW	208 V	55.1 kW	55.1 kW	97.0%	372–1,195 V	Nov 21, 2024	SB
SHP FLEX-US-21	84.9 kW	320 V	84.9 kW	84.9 kW	98.0%	495–1,195 V	Mar 11, 2025	SB
SHP FLEX-US-21	100.8 kW	380 V	100.8 kW	100.8 kW	98.0%	582–1,195 V	Mar 11, 2025	SB
SHP FLEX-US-21	100.8 kW	385 V	100.8 kW	100.8 kW	98.0%	582–1,195 V	Mar 11, 2025	SB
SHP FLEX-US-21	105 kW	400 V	105.6 kW	105.6 kW	98.0%	590–1,200 V	Nov 1, 2024	SB
SHP FLEX-US-21	112.7 kW	420 V	112.7 kW	112.7 kW	98.5%	630–1,195 V	Mar 11, 2025	SB
SHP FLEX-US-21	125 kW	480 V	125 kW	125 kW	98.5%	705–1,200 V	Jan 2, 2025	SB
SHP FLEX-US-21	150 kW	600 V	150.1 kW	150.1 kW	99.0%	880–1,200 V	Jan 2, 2025	SB
SHP FLEX-US-21	165 kW	630 V	165.7 kW	165.7 kW	99.0%	925–1,200 V	Jan 2, 2025	SB
SHP FLEX-US-21	172 kW	660 V	172.8 kW	172.8 kW	99.0%	968–1,200 V	Jan 2, 2025	SB

DC input (PV side)

CEC Grid Support Inverter List (Oct 7, 2026) · NLR SAM inverter library

CEC test DC voltages (min / nom / max)630 / 780 / 1,195 V
DC input at rated output (CEC test)115 kW

Efficiency

CEC Grid Support Inverter List (Oct 7, 2026) · NLR SAM inverter library

CEC weighted efficiency98.5%
Night-time standby (tare)3.17 W
Power to start converting171 W

CEC weighted efficiency is measured by an accredited lab at six power levels and three DC voltages — the number to compare between inverters.

Grid & smart-inverter certification

CEC Grid Support Inverter List (Oct 7, 2026)

UL 1741 SB (3rd ed.)Yes — UL, certificate Nov 30, 2022
UL 1741 SA (SA8–SA13)Yes — UL
Firmware tested (SA)3.15.22, 3.16.22
Volt-VAr with reactive power priority (SA13)Yes
Freq-Watt / Volt-Watt (SA14–15)Yes
Disable permit service / limit active power (SA17–18)Yes
CSIP (IEEE 2030.5) conformanceVia gateway during testing (Y*)
Monitor key data & scheduling (Rule 21 Phase 3)Yes (attested Mar 11, 2025)
CEC listedNov 1, 2024
Last CEC updateJan 2, 2025
CEC noteGrid Support Utility Interactive Inverter with a Nominal AC voltage range of 200 Vac - 600 Vac, and power output 50 kW - 172 kW.

UL 1741 SB is required for new interconnections in California (Rule 21) since 2026.

Panel compatibility & string sizing

NLR SAM inverter library · NLR PVWatts v8 · CEC PV Module List · Cali-Graf calculation

CityColdest air, °CHottest cell, °C

SHP FLEX-US-21: max DC 1,195 V · MPPT 630–1,195 V (CEC test window)

Most-permitted panels in Southern California

Panel	Power	Voc cold	Vmp hot	Panels per string	Installed together
Qcells Q.PEAK DUO BLK ML-G10.C+ 410	410 W	48.1 V	30.6 V	21–24	—
Qcells Q.PEAK DUO BLK ML-G10+ 410	410 W	48.1 V	30.6 V	21–24	—
LONGi LR5-54HABB-400M	400 W	39.3 V	25.3 V	25–30	—
JA Solar JAM54S31-405/MR	405 W	39.4 V	25.5 V	25–30	—
Hyundai Solutions HiN-T440NF(BK)	440 W	40.9 V	27 V	24–29	—
Silfab Solar SIL-440QD	440 W	41.1 V	28 V	23–29	—
Qcells Q.TRON BLK M-G2+ 430	430 W	41.3 V	28 V	23–28	—
Qcells Q.TRON BLK M-G2.H+ 430	430 W	41.3 V	28 V	23–28	—
REC Group REC460AA Pure-RX	460 W	68.8 V	47.1 V	14–17	—
Elin (Sirius PV) ELNSM54M-HC-410	410 W	39.3 V	25.3 V	25–30	—
Qcells Q.TRON BLK M-G2.C+ 430	430 W	41.3 V	28 V	23–28	—
Tesla TSP-420	420 W	43.4 V	27.7 V	23–27	—

Voltage check only, from CEC panel data and NLR weather for the city. Final design must follow the inverter manual and NEC 690.7.

About SMA

CEC Grid Support Inverter List (Oct 7, 2026)

ManufacturerSMA
Listed in CEC asSMA America
Websitesma-america.com
Models on CEC lists202

Other series

STP xx-US-80STP xx-US-50SHP xxx-US-21

Questions & answers

How efficient is the SMA SHP FLEX-US-21?

The California Energy Commission lists a weighted efficiency of 97.0–99.0% for SMA SHP FLEX-US-21 models, measured at six power levels and three DC voltages.

What sizes does the SMA SHP FLEX-US-21 come in?

The CEC list includes 10 models from 55 kW to 172 kW AC: SHP FLEX-US-21, SHP FLEX-US-21, SHP FLEX-US-21, SHP FLEX-US-21, SHP FLEX-US-21, SHP FLEX-US-21, SHP FLEX-US-21, SHP FLEX-US-21….

Is the SMA SHP FLEX-US-21 certified to UL 1741 SB?

Yes — the CEC Grid Support Inverter List shows UL 1741 SB for all models.

What is the SHP FLEX-US-21’s DC input voltage range?

CEC tested it at 630–1,195 V DC.

Sources

California Energy Commission — Grid Support Inverter List (solar and battery inverters), data as of Oct 7, 2026. Manufacturer-reported, confirmed by CEC against certificates and test reports.
NLR (formerly NREL) — System Advisor Model CEC inverter library (version 2026.7.3).
NLR (formerly NREL) — PVWatts v8, NSRDB PSM v3 typical-year weather for Los Angeles, Palmdale, Riverside, Santa Clarita, Chula Vista, Huntington Beach.
California Energy Commission — PV Module List (module electrical data for the compatibility check).
Cali-Graf calculations — formulas and inputs are shown next to each calculated value (efficiency from area, temperature-corrected voltages, string sizing, energy estimates).