Illustration · 120 half-cut cells

Solar panelLONGi

LONGi LR4-60HIBD-355M

Name: LONGi LR4-60HIBD-355M
Brand: LONGi

120 half-cut cells, bifacial, glass (dual-glass module). Power classes 345–365 W in the CEC list.

CEC listed · May 11, 2020UL 61730Bifacial

Power class

Power (STC)355 WCEC nameplate
Efficiency≈19.4%calculated from area
%/°C Pmax−0.334CEC listing test
PTC / STC94.3%PTC 335 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
LR4-60HIBD-345M	345 W	40.70	10.88	33.70	10.24	≈18.9%	325 W	May 11, 2020
LR4-60HIBD-350M	350 W	40.90	10.96	33.90	10.33	≈19.1%	330 W	May 11, 2020
LR4-60HIBD-355M	355 W	41.10	11.04	34.10	10.42	≈19.4%	335 W	May 11, 2020
LR4-60HIBD-360M	360 W	41.30	11.11	34.30	10.50	≈19.7%	340 W	May 11, 2020
LR4-60HIBD-365M	365 W	41.50	11.18	34.50	10.58	≈19.9%	345 W	May 11, 2020

≈ efficiency = Pmax ÷ CEC-listed area 1.83 m².

Build & dimensions

CEC PV Module List (Oct 7, 2026)

Module area1.83 m² (19.7 ft²)CEC-listed area
Cells120 half-cut cells
Back coverGlass (dual-glass module)

Heat & cold behaviour

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

	CEC listing test
Pmax coefficient γ	−0.334 %/°C
Voc coefficient β	−0.266 %/°C
Isc coefficient α	+0.053 %/°C
Operating cell temperature	NOCT 42.4 °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
345 W	254.9 W	31.36 V × 8.13 A	63.3 W	92%
350 W	258.8 W	31.55 V × 8.2 A	64.2 W	92%
355 W	262.5 W	31.74 V × 8.27 A	65.2 W	92%
360 W	266 W	31.92 V × 8.33 A	66 W	92%
365 W	269.7 W	32.11 V × 8.4 A	67 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

PVEL Scorecards

LONGi named Top Performer, 2017–2026

2023, 2024, 2025, 2026

RETC Overall Highest Achiever

LONGi, manufacturer level

This exact series is not listed in published PVEL Top Performer tables. Results below are for the manufacturer.

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

43.6 V

Voc when cold

per panel

27.6 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 IQ8PLUS-72-2-US	235–440 W	60 V	29–45 V	43.6 / 27.6 V	⚠ Works; below MPPT at peak heat	1.22
Enphase IQ8X-80-M-US	320–540 W	79.5 V	43–60 V	43.6 / 27.6 V	✗ Not a match: module voltage below MPPT range	0.93
APsystems (Alt Power System) DS3-L	265–570 W	60 V	28–45 V	43.6 / 27.6 V	⚠ Works; below MPPT at peak heat	0.46
Enphase IQ8M-72-2-US	260–460 W	60 V	30–45 V	43.6 / 27.6 V	⚠ Works; below MPPT at peak heat	1.09
Enphase IQ8A-72-2-US	295–500 W	60 V	32–45 V	43.6 / 27.6 V	⚠ Works; below MPPT at peak heat	1.02

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	595	11,900	6.08
Palmdale	1,835	651	13,028	6.69
Chula Vista	1,696	602	12,042	6.11
Huntington Beach	1,643	583	11,665	5.89
Riverside	1,696	602	12,042	6.21
Santa Clarita	1,724	612	12,240	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 355 W panels

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

Panel	Pmax	Efficiency	γ Pmax (CEC)	Voc, V	Isc, A	PVEL (product / brand)	SoCal permits (series)
LONGi LR4-60HIBD-355M	355 W	≈19.4%	−0.334	41.1	11.04	brand 9×	—
REC Group REC355AA	355 W	≈21.1%	−0.279	44	10.19	brand 9× (2016–2025)	30
Trina Solar TSM-355DE06X.05(II)	355 W	≈19.5%	−0.339	44.6	10.24	product 2022	23
Qcells Q.PEAK DUO-G8+ 355	355 W	≥19.8%	−0.343	40.95	10.79	product 2022	20

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 LR4-60HIBD-355M?

Calculated from the panel area (1.83 m²): about 19.4% for the 355 W class. 355 W over 1.83 m² equals about 194 W per square meter.

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

PVWatts v8 with typical-year weather gives about 595 kWh per year per 355 W panel in Los Angeles and about 651 kWh in Palmdale (20° roof, facing south, 14% system losses).

How much power does it lose on a hot roof?

With γ = −0.334 %/°C, at a 77 °C cell temperature (hottest modeled hour in Palmdale) output is about 17.3% 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 = 43.6 V, Vmp at 74 °C cell = 27.6 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; LONGi was named a Top Performer in 9 Scorecards (2017–2026). RETC named LONGi Overall Highest Achiever in 2023, 2024, 2025, 2026.

Sources

California Energy Commission — Solar Equipment Lists, PV Module List, Inverter List (snapshot Oct 7, 2026).
Qcells — manufacturer datasheet “Q.PEAK DUO-G8+ 345-360 EN ENDURING HIGH”.
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).