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Illustration · 120 half-cut cells
Solar panelWaaree

Waaree Bi-66 590

120 half-cut cells, bifacial, glass (dual-glass module). Power classes 580–605 W in the CEC list.

CEC listed · Apr 3, 2023UL 61730Bifacial
Power class
  • Power (STC)590 WCEC nameplate
  • Efficiency≈21.0%calculated from area
  • %/°C Pmax−0.369CEC listing test
  • PTC / STC92.7%PTC 547 W (CEC)

Power classes

CEC PV Module List (Oct 7, 2026) · Cali-Graf calculation · 6 models
ModelPmaxVoc, VIsc, AVmp, VImp, AEfficiencyPTCCEC listed
Bi-66-580580 W41.5617.7334.2116.96≈20.6%537 WApr 3, 2023
Bi-66-585585 W41.7617.7834.3417.04≈20.8%542 WApr 3, 2023
Bi-66-590590 W41.9017.8434.3917.16≈21.0%547 WApr 3, 2023
Bi-66-595595 W42.0517.9034.4417.29≈21.2%552 WApr 3, 2023
Bi-66-600600 W42.1817.9834.6217.35≈21.4%556 WApr 3, 2023
Bi-66-605605 W42.3518.0334.6817.46≈21.5%561 WApr 3, 2023
≈ efficiency = Pmax ÷ CEC-listed area 2.81 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−0.369 %/°C
Voc coefficient β−0.267 %/°C
Isc coefficient α+0.064 %/°C
Operating cell temperatureNOCT 46 °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
580 W430 W31.99 V × 13.44 A115.5 W100%
585 W433.7 W32.11 V × 13.5 A116.5 W100%
590 W437.4 W32.16 V × 13.6 A117.5 W100%
595 W441.3 W32.21 V × 13.7 A118.6 W100%
600 W445.2 W32.38 V × 13.75 A119.6 W100%
605 W448.8 W32.43 V × 13.84 A120.6 W100%
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
5
PVEL Scorecards
Waaree named Top Performer, 2022–2026
2025, 2026
RETC Overall Highest Achiever
Waaree, manufacturer level
This exact series is not listed in published PVEL Top Performer tables. Results below are for the manufacturer.

RETC PV Module Index — Waaree

YearRecognition
2024Test Category High Achiever
2025Overall Highest Achiever
2026Overall Highest Achiever; High achievement in performance; High achievement in reliability; Performance discipline high achiever (Temperature coefficient, Iam, Letid); Quality discipline high achiever (BOM verification); Reliability discipline high achiever (Damp heat, Pid, Tc)

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)
44.5 V
Voc when cold
per panel
27.1 V
Vmp when hot
per panel
13
Max panels / string
max DC 600 V
3
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 Vdatasheet3–13
Solis (Ginlong) S6-EH1P10K-H-US600 V80–520 Vdatasheet3–13
Solis (Ginlong) Solis-1P7.6K-4G-US600 V100–500 Vdatasheet4–13
Qcells Q.VOLT H7.6SX498 V234–498 VCEC test window9–11

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 Angeles1,67698911,8666.08
Palmdale1,8351,08312,9926.69
Chula Vista1,6961,00112,0086.11
Huntington Beach1,64396911,6325.89
Riverside1,6961,00112,0086.21
Santa Clarita1,7241,01712,2066.28
775Jan775Feb995Mar1,099Apr1,085May1,153Jun1,215Jul1,229Aug1,075Sep948Oct815Nov705DeckWh 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 590 W panels

CEC PV Module List (Oct 7, 2026) · Kiwa PVEL Scorecard · building permits
PanelPmaxEfficiencyγ Pmax (CEC)Voc, VIsc, APVEL (product / brand)SoCal permits (series)
Waaree Bi-66 590590 W≈21%−0.36941.917.84brand 5×—
Phono Solar PS590M8GFH-24/TNH590 W≈23%−0.2935313.78product 2024, 20251
Qcells Q.PEAK DUO XL-G11S.3/BFG 590590 W≈21.7%−0.34853.613.74product 2024, 2025, 20261
VSUN (Vietnam Sunergy) VSUN590N-144MH590 W≈22.9%−0.30952.4813.93brand 6× (2021–2026)1
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.

About Waaree

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

Other series by SoCal permits

WSMDi · 3BiN-21BiN-01BiN-02BiN-03BiN-05

Questions & answers

How efficient is the Waaree Bi-66 590?

Calculated from the panel area (2.81 m²): about 21% for the 590 W class. 590 W over 2.81 m² equals about 210 W per square meter.

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

PVWatts v8 with typical-year weather gives about 989 kWh per year per 590 W panel in Los Angeles and about 1,083 kWh in Palmdale (20° roof, facing south, 14% system losses).

How much power does it lose on a hot roof?

With γ = −0.369 %/°C, at a 77 °C cell temperature (hottest modeled hour in Palmdale) output is about 19.1% 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 = 44.5 V, Vmp at 74 °C cell = 27.1 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?

This exact series is not in published PVEL Top Performer tables; Waaree was named a Top Performer in 5 Scorecards (2022–2026). RETC named Waaree Overall Highest Achiever in 2025, 2026.

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 2022–2026.
  3. RETC — PV Module Index reports 2024–2026.
  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).