Illustration · 120 half-cut cells

Solar panelLONGi

LONGi LR4-60HPB-355M

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

120 half-cut cells. Power classes 335–370 W in the CEC list.

CEC listed · Oct 15, 2019UL 61730PVEL Top Performer 2021, 2022Installed in 193 SoCal permits

Power class

Power (STC)355 WCEC nameplate
Efficiency≈20.1%calculated from area
%/°C Pmax−0.339CEC listing test
PTC / STC93.4%PTC 332 W (CEC)

Power classes

CEC PV Module List (Oct 7, 2026) · Cali-Graf calculation · 8 models

Model	Pmax	Voc, V	Isc, A	Vmp, V	Imp, A	Efficiency	PTC	CEC listed
LR4-60HPB-335M	335 W	39.90	10.76	32.70	10.25	≈18.5%	312 W	Oct 15, 2019
LR4-60HPB-340M	340 W	40.10	10.84	32.90	10.34	≈18.8%	317 W	Oct 15, 2019
LR4-60HPB-345M	345 W	40.20	11.06	34.20	10.09	≈19.5%	322 W	Oct 15, 2019
LR4-60HPB-350M	350 W	40.40	11.16	34.40	10.18	≈19.8%	327 W	Oct 15, 2019
LR4-60HPB-355M	355 W	40.60	11.25	34.60	10.27	≈20.1%	332 W	Oct 15, 2019
LR4-60HPB-360M	360 W	40.80	11.33	34.80	10.35	≈20.3%	336 W	Oct 15, 2019
LR4-60HPB-365M	365 W	41.00	11.41	35.00	10.43	≈20.6%	341 W	Oct 15, 2019
LR4-60HPB-370M	370 W	41.20	11.50	35.20	10.52	≈20.9%	346 W	May 21, 2020

≈ efficiency = Pmax ÷ CEC-listed area 1.81 m².

Build & dimensions

CEC PV Module List (Oct 7, 2026)

Module area1.77 m² (19.1 ft²)CEC-listed area
Cells120 half-cut cells
Back coverBlack backsheet

Heat & cold behaviour

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

	CEC listing test
Pmax coefficient γ	−0.339 %/°C
Voc coefficient β	−0.266 %/°C
Isc coefficient α	+0.040 %/°C
Operating cell temperature	NOCT 45.2 °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
335 W	245.1 W	30.95 V × 7.92 A	62.4 W	93%
340 W	248.7 W	31.14 V × 7.99 A	63.3 W	93%
345 W	253.4 W	31.46 V × 8.06 A	64.7 W	94%
350 W	257.2 W	31.65 V × 8.13 A	65.6 W	94%
355 W	261 W	31.83 V × 8.2 A	66.6 W	94%
360 W	264.5 W	32.01 V × 8.26 A	67.5 W	94%
365 W	268.1 W	32.2 V × 8.33 A	68.4 W	94%
370 W	272 W	32.38 V × 8.4 A	69.4 W	94%

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, 2022

PVEL Top Performer

this series

Tests passed as Top Performer

LID+LETID, MSS, 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	LR4-60HPB-xxxM	MSS
2022	LR4-60HPB-xxxM	LID+LETIDMSSPIDTC

Tested bill of materials

Cell technology (tested BOM)p-type PERC
Module design (tested BOM)Monofacial - glass//backsheet
Power class range tested355-400W

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

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

43.1 V

Voc when cold

per panel

28.2 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	43.1 / 28.2 V	⚠ Works; below MPPT at peak heat	1.22
Enphase IQ8X-80-M-US	320–540 W	79.5 V	43–60 V	43.1 / 28.2 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	43.1 / 28.2 V	✓ Within range	0.46
Enphase IQ8M-72-2-US	260–460 W	60 V	30–45 V	43.1 / 28.2 V	⚠ Works; below MPPT at peak heat	1.09
Enphase IQ8A-72-2-US	295–500 W	60 V	32–45 V	43.1 / 28.2 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.

Who installs LR4-60HPB-xxxM panels in SoCal

building permits · CSLB License Master

193

Permits naming this series

Jan 2021 – Sep 2026

Licensed installers

CSLB license on the permit

Jurisdictions so far

LA County (unincorp.) (176), Palmdale (15), Los Angeles (2)

Sunpower

Orem · CSLB #961988

2 installsApr 2022 – Apr 2024Palmdale, Los Angeles

Dutchmen Construction Incorporated

Hemet · CSLB #1070131

1 installJul 2025Palmdale

Lightyear Solar LLC

Hemet · CSLB #1112970

1 installSep 2026Palmdale

Sunrun

Lehi · CSLB #750184

1 installJun 2022Los Angeles

Vertexbeta Inc

Woodland Hills · CSLB #1094438

1 installMay 2024Palmdale

Permits over time

Power class named in permit

355 W

100

350 W

360 W

365 W

345 W

Top ZIP codes

ZIP 9100138
ZIP 9172222
ZIP 9121417
ZIP 9101616
ZIP 9170212
ZIP 9172412
ZIP 9355011
ZIP 917448
Other ZIP codes13

Typical system

median 5.6 kW, 15 panels (n = 185)

Only installer and ZIP level is shown — no homeowner names, street addresses or permit numbers. Permits from LA County (unincorp.) come without a contractor license, so they count toward totals but not toward installers. Counts grow as more permit portals are loaded.

Installed together with

building permits

Microinverters

Enphase IQ7

Enphase IQ8+

Enphase IQ7+

Inverters

SolarEdge SE…H (HD-Wave)

106

Delta Electronics Ex-TL-US

Delta Electronics Mx-TL-US

Optimizers

SolarEdge Power Optimizer

Batteries

Enphase IQ Battery 5P

Number of permits naming both this panel series and the product; 161 of 193 permits list other equipment.

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 LR4-60HPB-355M	355 W	≈20.1%	−0.339	40.6	11.25	product 2021, 2022	193
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

LR5-54HABB-xxxM · 64LR5-54HPB-xxxM · 22LR4-60HPH-xxxM · 19LR5-72HBD-xxxM · 1LR4-60HBD-xxxM · 1LR5-78HBD-xxxM

Questions & answers

How efficient is the LONGi LR4-60HPB-355M?

Calculated from the panel area (1.77 m²): about 20.1% for the 355 W class. 355 W over 1.77 m² equals about 201 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 = −0.339 %/°C, at a 77 °C cell temperature (hottest modeled hour in Palmdale) output is about 17.6% 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 = 43.1 V, Vmp at 74 °C cell = 28.2 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 43.1 V vs max input 60 V; Vmp when hot 28.2 V vs MPPT low 28 V; recommended module power 265–570 W. Confirm on the microinverter maker’s compatibility list.

Has this panel been reliability-tested?

LR4-60HPB-xxxM was a PVEL Top Performer in 2021, 2022 (LID+LETID, MSS, PID, TC).

Who installs it in Southern California?

Building permits name this series 193 times (Jan 2021 – Sep 2026). The most active licensed installers are Sunpower, Dutchmen Construction Incorporated, Lightyear Solar LLC.

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 inverter library (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 — Los Angeles County Public Works (EPIC-LA, unincorporated areas) (Jan 2021 – Jun 2024); City of Palmdale (Mar 2024 – Sep 2026); LADBS, City of Los Angeles (Apr 2022 – Jun 2022). Equipment matched from permit descriptions by model number.
Contractors State License Board — License Master (contractor names and license status), as of Oct 5, 2026.
Cali-Graf calculations — formulas and inputs are shown next to each calculated value (efficiency from area, temperature-corrected voltages, string sizing, energy estimates).