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Illustration · 144 half-cut cells
Solar panelSinotec USA

Sinotec USA STS-550P-72BB

144 half-cut cells, bifacial, transparent backsheet. 550 W in the CEC list.

CEC listed · Jan 2, 2025UL 61730Bifacial
  • Power (STC)550 WCEC nameplate
  • Efficiency≈28.9%calculated from area
  • %/°C Pmax−0.331CEC listing test
  • PTC / STC94.1%PTC 518 W (CEC)

Electrical ratings (STC)

CEC PV Module List (Oct 7, 2026) · Cali-Graf calculation
ModelPmaxVoc, VIsc, AVmp, VImp, AEfficiencyPTCCEC listed
STS-550P-72BB550 W49.9214.0041.9613.11≈28.9%518 WJan 2, 2025
≈ efficiency = Pmax ÷ CEC-listed area 1.9 m².

Build & dimensions

CEC PV Module List (Oct 7, 2026)

Heat & cold behaviour

CEC PV Module List (Oct 7, 2026) · Cali-Graf calculation
CEC listing test
Pmax coefficient γ−0.331 %/°C
Voc coefficient β−0.262 %/°C
Isc coefficient α+0.062 %/°C
Operating cell temperatureNOCT 46.8 °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
550 W415.3 W39.58 V × 10.49 A107.1 W97%
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)
52.9 V
Voc when cold
per panel
33.9 V
Vmp when hot
per panel
11
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 Vdatasheet2–11
Solis (Ginlong) S6-EH1P10K-H-US600 V80–520 Vdatasheet3–11
Solis (Ginlong) Solis-1P7.6K-4G-US600 V100–500 Vdatasheet3–11
Qcells Q.VOLT H7.6SX498 V234–498 VCEC test window7–9

Microinverters (one per panel)

MicroinverterRecommended module powerMax DC inputMPPTVoc cold / Vmp hotCheckDC/AC
APsystems (Alt Power System) DS3-L265–570 W60 V28–45 V52.9 / 33.9 V✓ Within range0.71
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 Angeles1,67692211,9836.08
Palmdale1,8351,00913,1206.69
Chula Vista1,69693312,1266.11
Huntington Beach1,64390411,7475.89
Riverside1,69693312,1266.21
Santa Clarita1,72494812,3276.28
782Jan783Feb1,005Mar1,110Apr1,096May1,165Jun1,227Jul1,241Aug1,085Sep957Oct823Nov712DeckWh 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.

Compare with similar 550 W panels

CEC PV Module List (Oct 7, 2026) · Kiwa PVEL Scorecard · datasheets · building permits
PanelPmaxEfficiencyγ Pmax (CEC)Voc, VIsc, APVEL (product / brand)SoCal permits (series)
Sinotec USA STS-550P-72BB550 W≈28.9%−0.33149.9214——
JA Solar JAM72D30-550/MB550 W≈21.8%−0.33049.914product 2023, 20243
LONGi LR5-72HBD-550M550 W≥21.5%−0.35449.813.99product 20261
Canadian Solar CS6W-550MB-AG550 W≈21.4%−0.32449.614product 20241
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-550P-72BB?

Calculated from the panel area (1.9 m²): about 28.9% for the 550 W class. 550 W over 1.9 m² equals about 289 W per square meter.

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

PVWatts v8 with typical-year weather gives about 922 kWh per year per 550 W panel in Los Angeles and about 1,009 kWh in Palmdale (20° roof, facing south, 14% system losses).

How much power does it lose on a hot roof?

With γ = −0.331 %/°C, at a 77 °C cell temperature (hottest modeled hour in Palmdale) output is about 17.2% 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 2–11 panels per string (Voc at 2 °C = 52.9 V, Vmp at 74 °C cell = 33.9 V). Final design must follow the inverter manual and NEC 690.7.

Does it work with APsystems (Alt Power System) DS3-L microinverters?

Voltage check against the APsystems (Alt Power System) datasheet: Voc when cold 52.9 V vs max input 60 V; Vmp when hot 33.9 V vs MPPT low 28 V; recommended module power 265–570 W. Confirm on the microinverter maker’s compatibility list.

Is it bifacial?

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

Sources

  1. California Energy Commission — Solar Equipment Lists, PV Module List, Inverter List (snapshot Oct 7, 2026).
  2. LONGi — manufacturer datasheet “LR5-72HBD Suitable for distributed projects Advanced module technology delivers superior”.
  3. Canadian Solar — datasheet BiHiKu6 BIFACIAL MONO PERC CS6W-520|525|530|535|540|545|550MB-AG.
  4. Kiwa PVEL — PV Module Reliability Scorecard, Top Performer lists.
  5. NLR (formerly NREL) — System Advisor Model CEC module and inverter libraries (version 2026.7.3).
  6. NLR (formerly NREL) — PVWatts v8, NSRDB PSM v3 typical-year weather for Los Angeles, Palmdale, Chula Vista, Huntington Beach, Riverside, Santa Clarita.
  7. Inverter datasheets — APsystems (Alt Power System), Solis (Ginlong), Tesla (manufacturer documents).
  8. Building permits — Southern California permit portals. Equipment matched from permit descriptions.
  9. Cali-Graf calculations — formulas and inputs are shown next to each calculated value (efficiency from area, temperature-corrected voltages, string sizing, energy estimates).