Illustration · 108 half-cut cells

Solar panelWin Win Precision Technology

Win Win Precision Technology WST-445MGXB-E2

Name: Win Win Precision Technology WST-445MGXB-E2
Brand: Win Win Precision Technology

108 half-cut cells. Power classes 390–550 W in the CEC list.

CEC listed · Mar 21, 2023UL 61730

Power class

Power (STC)445 WCEC nameplate
Efficiency≈20.8%calculated from area
%/°C Pmax−0.347CEC listing test
PTC / STC92.6%PTC 412 W (CEC)

Power classes

CEC PV Module List (Oct 7, 2026) · Cali-Graf calculation · 16 models

Model	Pmax	Voc, V	Isc, A	Vmp, V	Imp, A	Efficiency	PTC	CEC listed
WST-390MGXB-E2	390 W	36.54	13.50	30.42	12.82	≈20.2%	359 W	Mar 21, 2023
WST-395MGXB-E2	395 W	36.74	13.55	30.63	12.88	≈20.5%	364 W	Mar 21, 2023
WST-400MGXB-E2	400 W	36.94	13.60	30.84	12.96	≈20.7%	368 W	Mar 21, 2023
WST-405MGXB-E2	405 W	37.14	13.65	31.03	13.05	≈21.0%	373 W	Mar 21, 2023
WST-410MGXB-E2	410 W	37.34	13.70	31.23	13.12	≈21.2%	378 W	Mar 21, 2023
WST-415MGXB-E2	415 W	37.38	14.02	31.19	13.31	≈21.5%	383 W	Mar 21, 2023
WST-440MGXB-E2	440 W	40.97	13.70	33.95	12.96	≈20.6%	407 W	Mar 21, 2023
WST-445MGXB-E2	445 W	41.08	13.77	34.10	13.05	≈20.8%	412 W	Mar 21, 2023
WST-450MGXB-E2	450 W	41.15	13.83	34.22	13.15	≈21.0%	417 W	Mar 21, 2023
WST-455MGXB-E2	455 W	41.28	13.90	34.29	13.27	≈21.3%	422 W	Mar 21, 2023
WST-460MGXB-E2	460 W	41.45	13.99	34.41	13.37	≈21.5%	426 W	Mar 21, 2023
WST-530MGXB-E2	530 W	49.25	13.71	41.06	12.91	≈20.7%	495 W	Mar 21, 2023
WST-535MGXB-E2	535 W	49.38	13.79	41.18	12.99	≈20.9%	500 W	Mar 21, 2023
WST-540MGXB-E2	540 W	49.51	13.85	41.32	13.07	≈21.1%	504 W	Mar 21, 2023
WST-545MGXB-E2	545 W	49.64	13.93	41.46	13.15	≈21.3%	509 W	Mar 21, 2023
WST-550MGXB-E2	550 W	49.77	14.00	41.59	13.23	≈21.5%	514 W	Mar 21, 2023

≈ efficiency = Pmax ÷ CEC-listed area 1.93 m².

Build & dimensions

CEC PV Module List (Oct 7, 2026)

Module area2.14 m² (23 ft²)CEC-listed area
Cells108 half-cut cells
Back coverBlack backsheet

Heat & cold behaviour

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

	CEC listing test
Pmax coefficient γ	−0.347 %/°C
Voc coefficient β	−0.258 %/°C
Isc coefficient α	+0.060 %/°C
Operating cell temperature	NOCT 47.3 °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
390 W	292.9 W	27.97 V × 10.47 A	77.1 W	99%
395 W	296.3 W	28.16 V × 10.52 A	78 W	99%
400 W	300.1 W	28.35 V × 10.59 A	79 W	99%
405 W	304.1 W	28.53 V × 10.66 A	80 W	99%
410 W	307.7 W	28.71 V × 10.72 A	81 W	99%
415 W	311.7 W	28.67 V × 10.87 A	82 W	99%
440 W	340.2 W	32.22 V × 10.56 A	88.6 W	101%
445 W	344.1 W	32.36 V × 10.63 A	89.7 W	101%
450 W	347.9 W	32.47 V × 10.71 A	90.7 W	101%
455 W	351.8 W	32.54 V × 10.81 A	91.7 W	101%
460 W	355.7 W	32.65 V × 10.89 A	92.7 W	101%
530 W	400.7 W	38.9 V × 10.3 A	102.7 W	97%
535 W	404.4 W	39 V × 10.37 A	103.4 W	97%
540 W	408.9 W	39.2 V × 10.43 A	104.6 W	97%
545 W	412.3 W	39.3 V × 10.49 A	105.8 W	97%
550 W	416.1 W	39.4 V × 10.56 A	106.5 W	97%

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

43.5 V

Voc when cold

per panel

27.3 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	3–13
Solis (Ginlong) S6-EH1P10K-H-US	600 V	80–520 V	datasheet	3–13
Solis (Ginlong) Solis-1P7.6K-4G-US	600 V	100–500 V	datasheet	4–13
Qcells Q.VOLT H7.6SX	498 V	234–498 V	CEC test window	9–11

Microinverters (one per panel)

Microinverter	Recommended module power	Max DC input	MPPT	Voc cold / Vmp hot	Check	DC/AC
Enphase IQ8X-80-M-US	320–540 W	79.5 V	43–60 V	43.5 / 27.3 V	✗ Not a match: module voltage below MPPT range	1.17
APsystems (Alt Power System) DS3-L	265–570 W	60 V	28–45 V	43.5 / 27.3 V	⚠ Works; below MPPT at peak heat	0.57
Enphase IQ8M-72-2-US	260–460 W	60 V	30–45 V	43.5 / 27.3 V	⚠ Works; below MPPT at peak heat	1.37
Enphase IQ8A-72-2-US	295–500 W	60 V	32–45 V	43.5 / 27.3 V	⚠ Works; below MPPT at peak heat	1.28

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	746	11,933	6.08
Palmdale	1,835	817	13,065	6.69
Chula Vista	1,696	755	12,076	6.11
Huntington Beach	1,643	731	11,698	5.89
Riverside	1,696	755	12,076	6.21
Santa Clarita	1,724	767	12,275	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 445 W panels

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

Panel	Pmax	Efficiency	γ Pmax (CEC)	Voc, V	Isc, A	Warranty	PVEL (product / brand)	SoCal permits (series)
Win Win Precision Technology WST-445MGXB-E2	445 W	≈20.8%	−0.347	41.08	13.77	—	—	—
Qcells Q.TRON BLK M-G2+ 445	445 W	≈22.8%	−0.276	40.16	13.98	25 / 25 yr	brand 11× (2016–2026)	40
Silfab Solar SIL-440QD	440 W	≈22.6%	−0.294	38.97	14.25	25 / 30 yr	brand 7× (2017–2025)	39
Hyundai Energy Solutions HiN-T445NF(BK)	445 W	≈22.9%	−0.298	39	14.46	25 / 30 yr	brand 5× (2017–2025)	37

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 Win Win Precision Technology WST-445MGXB-E2?

Calculated from the panel area (2.14 m²): about 20.8% for the 445 W class. 445 W over 2.14 m² equals about 208 W per square meter.

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

PVWatts v8 with typical-year weather gives about 746 kWh per year per 445 W panel in Los Angeles and about 817 kWh in Palmdale (20° roof, facing south, 14% system losses).

How much power does it lose on a hot roof?

With γ = −0.347 %/°C, at a 77 °C cell temperature (hottest modeled hour in Palmdale) output is about 18% 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 3–13 panels per string (Voc at 2 °C = 43.5 V, Vmp at 74 °C cell = 27.3 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.TRON BLK M-G2+ SERIES 415–440 Wp”.
Silfab Solar — datasheet NTC SIL-420 QD CELL TECHNOLOGY.
Hyundai Energy Solutions — datasheet [US] NF(BK)(HiN) Series (N TOPCon Bifacial) 435~445W.
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).