Illustration · 144 half-cut cells

Solar panelLONGi

LONGi LR4-72HIBD-425M

Name: LONGi LR4-72HIBD-425M
Brand: LONGi

144 half-cut cells, bifacial. Power classes 415–435 W in the CEC list.

CEC listed · Mar 11, 2020UL 61730BifacialPVEL Top Performer 2021

Power class

Power (STC)425 WCEC nameplate
Efficiency≈19.5%calculated from area
%/°C Pmax−0.329CEC listing test
PTC / STC94.2%PTC 400 W (CEC)

Power classes

CEC PV Module List (Oct 7, 2026) · Cali-Graf calculation · 5 models

Model	Pmax	Voc, V	Isc, A	Vmp, V	Imp, A	Efficiency	PTC	CEC listed
LR4-72HIBD-415M	415 W	49.00	10.89	40.60	10.23	≈19.0%	391 W	Mar 11, 2020
LR4-72HIBD-420M	420 W	49.20	10.96	40.80	10.30	≈19.3%	396 W	Mar 11, 2020
LR4-72HIBD-425M	425 W	49.40	11.02	41.00	10.37	≈19.5%	400 W	Mar 11, 2020
LR4-72HIBD-430M	430 W	49.60	11.09	41.20	10.44	≈19.7%	405 W	Mar 11, 2020
LR4-72HIBD-435M	435 W	49.80	11.16	41.40	10.51	≈20.0%	410 W	Mar 11, 2020

≈ efficiency = Pmax ÷ CEC-listed area 2.18 m².

Heat & cold behaviour

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

	CEC listing test
Pmax coefficient γ	−0.329 %/°C
Voc coefficient β	−0.266 %/°C
Isc coefficient α	+0.049 %/°C
Operating cell temperature	NOCT 43.1 °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
415 W	310.3 W	37.91 V × 8.18 A	76.4 W	92%
420 W	313.9 W	38.1 V × 8.24 A	77.3 W	92%
425 W	317.5 W	38.28 V × 8.29 A	78.1 W	92%
430 W	321.2 W	38.47 V × 8.35 A	79.1 W	92%
435 W	325 W	38.66 V × 8.41 A	80 W	92%

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

2021

PVEL Top Performer

this series

Tests passed as Top Performer

PID, TC

PVEL Scorecards

LONGi named Top Performer, 2017–2026

2023, 2024, 2025, 2026

RETC Overall Highest Achiever

LONGi, manufacturer level

PVEL Top Performer tests

Year	Product	Tests
2021	LR4-72HIBD-xxxM	PIDTC

RETC PV Module Index — LONGi

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

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

52.4 V

Voc when cold

per panel

33.4 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	2–11
Solis (Ginlong) S6-EH1P10K-H-US	600 V	80–520 V	datasheet	3–11
Solis (Ginlong) Solis-1P7.6K-4G-US	600 V	100–500 V	datasheet	3–11
Qcells Q.VOLT H7.6SX	498 V	234–498 V	CEC test window	8–9

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	52.4 / 33.4 V	✓ Within range	1.47
Enphase IQ8X-80-M-US	320–540 W	79.5 V	43–60 V	52.4 / 33.4 V	✗ Not a match: module voltage below MPPT range	1.12
APsystems (Alt Power System) DS3-L	265–570 W	60 V	28–45 V	52.4 / 33.4 V	✓ Within range	0.54
Enphase IQ8M-72-2-US	260–460 W	60 V	30–45 V	52.4 / 33.4 V	✓ Within range	1.31
Enphase IQ8A-72-2-US	295–500 W	60 V	32–45 V	52.4 / 33.4 V	✓ Within range	1.22

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	712	11,397	6.08
Palmdale	1,835	780	12,478	6.69
Chula Vista	1,696	721	11,533	6.11
Huntington Beach	1,643	698	11,172	5.89
Riverside	1,696	721	11,533	6.21
Santa Clarita	1,724	733	11,723	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 425 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)
LONGi LR4-72HIBD-425M	425 W	≈19.5%	−0.329	49.4	11.02	—	product 2021	—
Canadian Solar CS3N-425MS	425 W	≥20.9%	−0.332	45.5	11.8	25 yr	product 2023	46
Qcells Q.TRON BLK M-G2+ 425	425 W	≥21.8%	−0.276	39.03	13.66	25 / 25 yr	brand 11× (2016–2026)	40
Silfab Solar SIL-425QD	425 W	≈21.8%	−0.294	38.88	13.68	25 / 30 yr	brand 7× (2017–2025)	39

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 LONGi

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

ManufacturerLONGi
Listed in CEC asLONGi Green Energy Technology Co., Ltd.
Websitelongi.com
PVEL Top Performer (manufacturer)9 Scorecards (2017–2026)
RETC PV Module Index2023, 2024, 2025, 2026
Current panel series in CEC list25

Other series by SoCal permits

LR4-60HPB-xxxM · 193LR5-54HABB-xxxM · 64LR5-54HPB-xxxM · 22LR4-60HPH-xxxM · 19LR5-72HBD-xxxM · 1LR4-60HBD-xxxM · 1

Questions & answers

How efficient is the LONGi LR4-72HIBD-425M?

Calculated from the panel area (2.18 m²): about 19.5% for the 425 W class. 425 W over 2.18 m² equals about 195 W per square meter.

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

PVWatts v8 with typical-year weather gives about 712 kWh per year per 425 W panel in Los Angeles and about 780 kWh in Palmdale (20° roof, facing south, 14% system losses).

How much power does it lose on a hot roof?

With γ = −0.329 %/°C, at a 77 °C cell temperature (hottest modeled hour in Palmdale) output is about 17% 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 = 52.4 V, Vmp at 74 °C cell = 33.4 V). Final design must follow the inverter manual and NEC 690.7.

Does it work with Enphase IQ8PLUS-72-2-US microinverters?

Voltage check against the Enphase datasheet: Voc when cold 52.4 V vs max input 60 V; Vmp when hot 33.4 V vs MPPT low 29 V; recommended module power 235–440 W. Confirm on the microinverter maker’s compatibility list.

Is it bifacial?

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

Has this panel been reliability-tested?

LR4-72HIBD-xxxM was a PVEL Top Performer in 2021 (PID, TC).

Sources

California Energy Commission — Solar Equipment Lists, PV Module List, Inverter List (snapshot Oct 7, 2026).
Canadian Solar — manufacturer datasheet “HiKu Mono PERC CS3N-400|405|410|415|420|425MS MORE POWER”.
Qcells — manufacturer datasheet “Q.TRON BLK M-G2+ SERIES 415–440 Wp”.
Silfab Solar — datasheet NTC SIL-420 QD CELL TECHNOLOGY.
Kiwa PVEL — PV Module Reliability Scorecard, Top Performer lists 2017–2026.
RETC — PV Module Index reports 2023–2026.
NLR (formerly NREL) — System Advisor Model CEC module and inverter libraries (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).