Illustration · 108 half-cut cells

Solar panelSinotec USA

Sinotec USA STS-400P-54DD

Name: Sinotec USA STS-400P-54DD
Brand: Sinotec USA

108 half-cut cells. Power classes 385–415 W in the CEC list.

CEC listed · Dec 11, 2023UL 61730

Power class

Power (STC)400 WCEC nameplate
Efficiency≈20.6%calculated from area
%/°C Pmax−0.364CEC listing test
PTC / STC93.9%PTC 376 W (CEC)

Power classes

CEC PV Module List (Oct 7, 2026) · Cali-Graf calculation · 7 models

Model	Pmax	Voc, V	Isc, A	Vmp, V	Imp, A	Efficiency	PTC	CEC listed
STS-385P-54DD	385 W	36.60	13.25	30.70	12.55	≈19.8%	361 W	Dec 11, 2023
STS-390P-54DD	390 W	36.80	13.34	30.90	12.62	≈20.1%	366 W	Dec 11, 2023
STS-395P-54DD	395 W	37.00	13.43	31.10	12.70	≈20.4%	371 W	Dec 11, 2023
STS-400P-54DD	400 W	37.20	13.54	31.30	12.80	≈20.6%	376 W	Dec 11, 2023
STS-405P-54DD	405 W	37.40	13.66	31.40	12.89	≈20.9%	380 W	Dec 11, 2023
STS-410P-54DD	410 W	37.60	13.77	31.60	12.98	≈21.1%	385 W	Dec 11, 2023
STS-415P-54DD	415 W	37.80	13.87	31.80	13.06	≈21.4%	390 W	Dec 11, 2023

≈ efficiency = Pmax ÷ CEC-listed area 1.94 m².

Build & dimensions

CEC PV Module List (Oct 7, 2026)

Module area1.94 m² (20.9 ft²)CEC-listed area
Cells108 half-cut cells
Back coverBlack backsheet
FrameBlack frame

Heat & cold behaviour

CEC PV Module List (Oct 7, 2026) · Cali-Graf calculation

	CEC listing test
Pmax coefficient γ	−0.364 %/°C
Voc coefficient β	−0.246 %/°C
Isc coefficient α	+0.006 %/°C
Operating cell temperature	NOCT 42.6 °C

Vmp coefficient ≈ γ − α (CEC); used only for the hot-roof voltage estimate.

Away from lab conditions — CEC listing test points

Class	Pmax at NOCT	Vmp × Imp at NOCT	Pmax at 200 W/m²	Low-light efficiency vs STC
385 W	290.6 W	28.1 V × 10.34 A	76.7 W	100%
390 W	294.3 W	28.3 V × 10.4 A	77.8 W	100%
395 W	297.1 W	28.4 V × 10.46 A	78.6 W	99%
400 W	301.4 W	28.6 V × 10.54 A	79.9 W	100%
405 W	304.8 W	28.7 V × 10.62 A	80.7 W	100%
410 W	308.9 W	28.9 V × 10.69 A	81.7 W	100%
415 W	313.1 W	29.1 V × 10.76 A	82.7 W	100%

Pmax = Vmp × Imp from the CEC listing; low-light efficiency = Pmax at 200 W/m² ÷ (20% of STC Pmax).

Inverter compatibility & string sizing

CEC PV Module List (Oct 7, 2026) · Cali-Graf calculation · NLR PVWatts v8 · inverter datasheets · NLR SAM inverter library · CEC Grid Support Inverter List (Oct 7, 2026)

CityColdest air, °CHottest cell, °CString inverter

39.3 V

Voc when cold

per panel

25.6 V

Vmp when hot

per panel

Max panels / string

max DC 600 V

Min panels / string

MPPT from 60 V

Defaults come from NLR TMY weather (coldest hour, hottest modeled cell). Code calculations (NEC 690.7) use the ASHRAE extreme annual minimum, which is usually colder — enter it above. β is the CEC-measured coefficient; NEC 690.7 calculations use the datasheet value.

String inverters most named in SoCal permits

Inverter	Max DC input	MPPT	Window source	Panels per string
Tesla 1538000-xx-y	600 V	60–480 V	datasheet	3–15
Solis (Ginlong) S6-EH1P10K-H-US	600 V	80–520 V	datasheet	4–15
Solis (Ginlong) Solis-1P7.6K-4G-US	600 V	100–500 V	datasheet	4–15
Qcells Q.VOLT H7.6SX	498 V	234–498 V	CEC test window	10–12

Microinverters (one per panel)

Microinverter	Recommended module power	Max DC input	MPPT	Voc cold / Vmp hot	Check	DC/AC
Enphase IQ8PLUS-72-2-US	235–440 W	60 V	29–45 V	39.3 / 25.6 V	⚠ Works; below MPPT at peak heat	1.38
Enphase IQ8X-80-M-US	320–540 W	79.5 V	43–60 V	39.3 / 25.6 V	✗ Not a match: module voltage below MPPT range	1.05
APsystems (Alt Power System) DS3-L	265–570 W	60 V	28–45 V	39.3 / 25.6 V	⚠ Works; below MPPT at peak heat	0.51
Enphase IQ8M-72-2-US	260–460 W	60 V	30–45 V	39.3 / 25.6 V	⚠ Works; below MPPT at peak heat	1.23
Enphase IQ8A-72-2-US	295–500 W	60 V	32–45 V	39.3 / 25.6 V	✗ Not a match: module voltage below MPPT range	1.15

Voltage check against the microinverter datasheets — confirm the pairing on the manufacturer’s module compatibility list. Rows appear only when the panel’s power is inside the microinverter’s recommended module power range.

SolarEdge and other optimizer-based systems size strings by the optimizer rules — use the manufacturer’s designer. Reference inverters: most named in SoCal permits since Oct 2024.

Expected production in Southern California

NLR PVWatts v8 · Cali-Graf calculation

PanelsCity for chartSystem size

City	kWh / kW / yr	kWh / panel / yr	kWh / system / yr	Sun, kWh/m²/day
Los Angeles	1,676	670	12,067	6.08
Palmdale	1,835	734	13,212	6.69
Chula Vista	1,696	678	12,211	6.11
Huntington Beach	1,643	657	11,830	5.89
Riverside	1,696	678	12,211	6.21
Santa Clarita	1,724	690	12,413	6.28

Estimate for comparison, not a quote: shading, roof orientation and local losses change real output. Roof mount, 20° tilt, south, 14% system losses.

Compare with similar 400 W panels

CEC PV Module List (Oct 7, 2026) · Qcells datasheet · Kiwa PVEL Scorecard · building permits

Panel	Pmax	Efficiency	γ Pmax (CEC)	Voc, V	Isc, A	PVEL (product / brand)	SoCal permits (series)
Sinotec USA STS-400P-54DD	400 W	≈20.6%	−0.364	37.2	13.54	—	—
Qcells Q.PEAK DUO BLK ML-G10+ 400	400 W	≥20.4%	−0.362	45.3	11.14	product 2022, 2023	221
JA Solar JAM54S31-400/MR	400 W	≈21.1%	−0.329	37.07	13.79	product 2023, 2024	152
REC Group REC400AA Pure	400 W	≈22.3%	−0.256	48.8	10.25	brand 9× (2016–2025)	66

Same fields from the same sources for every row; ≈ efficiency is calculated from the listed area. Comparable series: other brands, same product group, power range covering this class.

Questions & answers

How efficient is the Sinotec USA STS-400P-54DD?

Calculated from the panel area (1.94 m²): about 20.6% for the 400 W class. 400 W over 1.94 m² equals about 206 W per square meter.

How much energy does one panel produce in Los Angeles or Palmdale?

PVWatts v8 with typical-year weather gives about 670 kWh per year per 400 W panel in Los Angeles and about 734 kWh in Palmdale (20° roof, facing south, 14% system losses).

How much power does it lose on a hot roof?

With γ = −0.364 %/°C, at a 77 °C cell temperature (hottest modeled hour in Palmdale) output is about 18.9% below the STC rating.

How many panels fit on one string?

With the Tesla 1538000-xx-y (max DC 600 V, MPPT from 60 V, datasheet) in Los Angeles the calculator gives 3–15 panels per string (Voc at 2 °C = 39.3 V, Vmp at 74 °C cell = 25.6 V). Final design must follow the inverter manual and NEC 690.7.

Sources

California Energy Commission — Solar Equipment Lists, PV Module List, Inverter List (snapshot Oct 7, 2026).
Qcells — manufacturer datasheet “Q.PEAK DUO BLK ML-G10+ ENDURING HIGH PERFORMANCE”.
Kiwa PVEL — PV Module Reliability Scorecard, Top Performer lists.
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, Chula Vista, Huntington Beach, Riverside, Santa Clarita.
Inverter datasheets — APsystems (Alt Power System), Enphase, Solis (Ginlong), Tesla (manufacturer documents).
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).