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Illustration · 132 half-cut cells
Solar panelQcells

Qcells Q.PEAK DUO ML-G12S.7/BFG 665

132 half-cut cells, bifacial. Power classes 660–675 W in the CEC list.

CEC listed · Dec 11, 2025UL 61730BifacialPVEL Top Performer 2026
Power class
  • Power (STC)665 WCEC nameplate
  • Efficiency≈21.9%calculated from area
  • %/°C Pmax−0.324CEC listing test
  • PTC / STC93.6%PTC 622 W (CEC)

Power classes

CEC PV Module List (Oct 7, 2026) · Cali-Graf calculation · 4 models
ModelPmaxVoc, VIsc, AVmp, VImp, AEfficiencyPTCCEC listed
Q.PEAK DUO ML-G12S.7/BFG 660660 W45.6818.3637.9417.39≈21.8%617 WDec 11, 2025
Q.PEAK DUO ML-G12S.7/BFG 665665 W45.7018.3938.1117.45≈21.9%622 WDec 11, 2025
Q.PEAK DUO ML-G12S.7/BFG 670670 W45.7218.4238.2717.51≈22.1%627 WDec 11, 2025
Q.PEAK DUO ML-G12S.7/BFG 675675 W45.7418.4538.4317.56≈22.3%632 WDec 11, 2025
≈ efficiency = Pmax ÷ CEC-listed area 3.03 m².

Heat & cold behaviour

CEC PV Module List (Oct 7, 2026) · Cali-Graf calculation
CEC listing test
Pmax coefficient γ−0.324 %/°C
Voc coefficient β−0.242 %/°C
Isc coefficient α+0.034 %/°C
Operating cell temperatureNOCT 46.3 °C
Vmp coefficient ≈ γ − α (CEC); used only for the hot-roof voltage estimate.

Away from lab conditions — CEC listing test points

ClassPmax at NOCTVmp × Imp at NOCTPmax at 200 W/m²Low-light efficiency vs STC
660 W487.4 W35.77 V × 13.62 A126.9 W96%
665 W491.2 W35.93 V × 13.67 A127.9 W96%
670 W495 W36.08 V × 13.72 A128.8 W96%
675 W498.5 W36.23 V × 13.76 A129.7 W96%
Pmax = Vmp × Imp from the CEC listing; low-light efficiency = Pmax at 200 W/m² ÷ (20% of STC Pmax).

Independent reliability testing

Kiwa PVEL Scorecard · RETC PV Module Index
2026
PVEL Top Performer
this series
5
Tests passed as Top Performer
DH, HSS, LID+LETID, MSS, UVID
11
PVEL Scorecards
Qcells named Top Performer, 2016–2026
2023, 2026
RETC Overall Highest Achiever
Qcells, manufacturer level

PVEL Top Performer tests

YearProductTests
2026Q.PEAK DUO ML-G12S.7/BFGDHHSSLID+LETIDMSSUVID

Tested bill of materials

Details describe the tested sample, not every module of the series.

RETC PV Module Index — Qcells

YearRecognition
2023Overall Highest Achiever; High Achievement in Performance (Module efficiency, Pan file performance); High Achievement in Reliability (Damp heat test, Pid resistance, Thermal cycle test)
2024High Achievement in Performance
2025Performance High Achiever
2026Overall Highest Achiever; High achievement in performance; High achievement in reliability; Performance discipline high achiever (Conversion efficiency, Iam, Letid, Lid, PTC-to-STC, Temperature coefficient); Quality discipline high achiever (BOM verification); Reliability discipline high achiever (Sdml, Tc, Uvid, Budt, Damp heat, Hdt, Pid)

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)
48.2 V
Voc when cold
per panel
31.4 V
Vmp when hot
per panel
12
Max panels / string
max DC 600 V
2
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

InverterMax DC inputMPPTWindow sourcePanels per string
Tesla 1538000-xx-y600 V60–480 Vdatasheet2–12
Solis (Ginlong) S6-EH1P10K-H-US600 V80–520 Vdatasheet3–12
Solis (Ginlong) Solis-1P7.6K-4G-US600 V100–500 Vdatasheet4–12
Qcells Q.VOLT H7.6SX498 V234–498 VCEC test window8–10

Microinverters (one per panel)

No microinverter in the reference set lists this power class in its recommended module power range.
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
CitykWh / kW / yrkWh / panel / yrkWh / system / yrSun, kWh/m²/day
Los Angeles1,6761,11512,2606.08
Palmdale1,8351,22013,4236.69
Chula Vista1,6961,12812,4066.11
Huntington Beach1,6431,09312,0195.89
Riverside1,6961,12812,4066.21
Santa Clarita1,7241,14612,6116.28
800Jan801Feb1,028Mar1,135Apr1,121May1,192Jun1,255Jul1,270Aug1,110Sep979Oct842Nov729DeckWh per month · Los Angeles
Estimate for comparison, not a quote: shading, roof orientation and local losses change real output. Roof mount, 20° tilt, south, 14% system losses.

About Qcells

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

Other series by SoCal permits

Q.PEAK DUO BLK ML-G10+ · 221Q.PEAK DUO BLK ML-G10.C+ · 124Q.TRON BLK M-G2+ · 40Q.TRON BLK M-G2.H+ · 33Q.TRON BLK M-G2.C+ · 24Q.TRON M-G2+ · 20

Questions & answers

How efficient is the Qcells Q.PEAK DUO ML-G12S.7/BFG 665?

Calculated from the panel area (3.03 m²): about 21.9% for the 665 W class. 665 W over 3.03 m² equals about 219 W per square meter.

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

PVWatts v8 with typical-year weather gives about 1,115 kWh per year per 665 W panel in Los Angeles and about 1,220 kWh in Palmdale (20° roof, facing south, 14% system losses).

How much power does it lose on a hot roof?

With γ = −0.324 %/°C, at a 77 °C cell temperature (hottest modeled hour in Palmdale) output is about 16.8% 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 2–12 panels per string (Voc at 2 °C = 48.2 V, Vmp at 74 °C cell = 31.4 V). Final design must follow the inverter manual and NEC 690.7.

Is it bifacial?

Yes. Rear gain depends on mounting height and ground reflectance.

Has this panel been reliability-tested?

Q.PEAK DUO ML-G12S.7/BFG was a PVEL Top Performer in 2026 (DH, HSS, LID+LETID, MSS, UVID).

Sources

  1. California Energy Commission — Solar Equipment Lists, PV Module List, Inverter List (snapshot Oct 7, 2026).
  2. Kiwa PVEL — PV Module Reliability Scorecard, Top Performer lists 2016–2026.
  3. RETC — PV Module Index reports 2023–2026.
  4. NLR (formerly NREL) — System Advisor Model CEC module and inverter libraries (version 2026.7.3).
  5. NLR (formerly NREL) — PVWatts v8, NSRDB PSM v3 typical-year weather for Los Angeles, Palmdale, Chula Vista, Huntington Beach, Riverside, Santa Clarita.
  6. Inverter datasheets — Solis (Ginlong), Tesla (manufacturer documents).
  7. Building permits — Southern California permit portals. Equipment matched from permit descriptions.
  8. Cali-Graf calculations — formulas and inputs are shown next to each calculated value (efficiency from area, temperature-corrected voltages, string sizing, energy estimates).