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MicroinverterRelyEZ Energy Storage Technology

RelyEZ Energy Storage Technology Sync Micro 660S

Microinverter. 3 models, 550 W–760 W AC at 240 V.

UL 1741 SBCEC listed · May 1, 2025

Model

Rated AC power660 W
CEC weighted efficiency94.5%

Models & power ratings

CEC Grid Support Inverter List (Oct 7, 2026) · NLR SAM inverter library · 3 models

Model	Nominal AC	Grid voltage	CEC continuous	Rated AC (SAM)	CEC weighted eff.	DC test window	CEC listed	UL 1741 SB
Sync Micro 550S	550 W	240 V	550 W	550 W	94.0%	36–76 V	May 1, 2025	SB
Sync Micro 660S	660 W	240 V	660 W	660 W	94.5%	43–76 V	May 1, 2025	SB
Sync Micro 760S	760 W	240 V	760 W	760 W	95.0%	50–76 V	May 1, 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)43 / 60 / 76 V
DC input at rated output (CEC test)687 W

Efficiency

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

CEC weighted efficiency94.5%
Night-time standby (tare)0.03 W
Power to start converting12 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 — Intertek, certificate Feb 24, 2025
UL 1741 SA (SA8–SA13)No
Volt-VAr with reactive power priority (SA13)No
Freq-Watt / Volt-Watt (SA14–15)No
Disable permit service / limit active power (SA17–18)No
CSIP (IEEE 2030.5) conformanceNo
Monitor key data & scheduling (Rule 21 Phase 3)No
CEC listedMay 1, 2025

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

Sync Micro 660S: max DC 76 V · MPPT 43–76 V (CEC test window)

Most-permitted panels in Southern California

Panel	Power	Voc cold / Vmp hot	Check	DC/AC	Installed together
Qcells Q.PEAK DUO BLK ML-G10.C+ 410	410 W	48.1 / 30.6 V	⚠ Below MPPT at peak heat	0.62	—
Qcells Q.PEAK DUO BLK ML-G10+ 410	410 W	48.1 / 30.6 V	⚠ Below MPPT at peak heat	0.62	—
LONGi LR5-54HABB-400M	400 W	39.3 / 25.3 V	⚠ Below MPPT at peak heat	0.61	—
JA Solar JAM54S31-405/MR	405 W	39.4 / 25.5 V	⚠ Below MPPT at peak heat	0.61	—
Hyundai Solutions HiN-T440NF(BK)	440 W	40.9 / 27 V	⚠ Below MPPT at peak heat	0.67	—
Silfab Solar SIL-440QD	440 W	41.1 / 28 V	⚠ Below MPPT at peak heat	0.67	—
Qcells Q.TRON BLK M-G2+ 430	430 W	41.3 / 28 V	⚠ Below MPPT at peak heat	0.65	—
Qcells Q.TRON BLK M-G2.H+ 430	430 W	41.3 / 28 V	⚠ Below MPPT at peak heat	0.65	—
REC Group REC460AA Pure-RX	460 W	68.8 / 47.1 V	✓ Within range	0.7	—
Elin (Sirius PV) ELNSM54M-HC-410	410 W	39.3 / 25.3 V	⚠ Below MPPT at peak heat	0.62	—
Qcells Q.TRON BLK M-G2.C+ 430	430 W	41.3 / 28 V	⚠ Below MPPT at peak heat	0.65	—
Tesla TSP-420	420 W	43.4 / 27.7 V	⚠ Below MPPT at peak heat	0.64	—

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

Compare with similar 660 W inverters

CEC Grid Support Inverter List (Oct 7, 2026) · building permits

Inverter	Power	CEC weighted eff.	DC test window	UL 1741 SB	Latest CEC	SoCal permits
RelyEZ Energy Storage Technology Sync Micro xxxS	550 W–760 W	94.5%	43–76 V	Yes	2025	0
Enphase Energy IQ8 Series	240 W–633 W	97.5%	25–95 V	44 of 45	2025	1,104
Hoymiles HM-xxxNT	295 W–1.44 kW	96.5%	29–48 V	11 of 12	2023	3
Power Center Dxxx-M2	696 W–696 W	96.5%	33–48 V	Yes	2022	2
FOXESS M1-xxxx-NA	600 W–1.2 kW	95.5%	35–50 V	Yes	2026	—

Same type and grid voltage, power range covering this model; same fields from the same sources.

Questions & answers

How efficient is the RelyEZ Energy Storage Technology Sync Micro xxxS?

The California Energy Commission lists a weighted efficiency of 94.0–95.0% for RelyEZ Energy Storage Technology Sync Micro xxxS models, measured at six power levels and three DC voltages.

What sizes does the RelyEZ Energy Storage Technology Sync Micro xxxS come in?

The CEC list includes 3 models from 550 W to 760 W AC: Sync Micro 550S, Sync Micro 660S, Sync Micro 760S.

Is the RelyEZ Energy Storage Technology Sync Micro xxxS certified to UL 1741 SB?

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

What is the Sync Micro 660S’s DC input voltage range?

CEC tested it at 43–76 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).
Building permits — Southern California permit portals. Equipment matched from permit descriptions.
Cali-Graf calculations — formulas and inputs are shown next to each calculated value (efficiency from area, temperature-corrected voltages, string sizing, energy estimates).