Illustration · 96 cells

Solar panelMaxeon Solar Technologies

Maxeon Solar Technologies SPR-X21-335-BLK

Name: Maxeon Solar Technologies SPR-X21-335-BLK
Brand: Maxeon Solar Technologies

96 cells. Power classes 335–350 W in the CEC list.

CEC listed · Feb 21, 2023UL 61730

Power class

Power (STC)335 WCEC nameplate
Efficiency≈20.6%calculated from area
%/°C Pmax−0.331CEC listing test
PTC / STC93.6%PTC 314 W (CEC)

Power classes

CEC PV Module List (Oct 7, 2026) · Cali-Graf calculation · 2 models

Model	Pmax	Voc, V	Isc, A	Vmp, V	Imp, A	Efficiency	PTC	CEC listed
SPR-X21-335-BLK	335 W	67.90	6.23	57.30	5.85	≈20.6%	314 W	Feb 21, 2023
SPR-X21-350-BLK	350 W	68.20	6.50	58.40	5.99	≈21.5%	328 W	Feb 21, 2023

≈ efficiency = Pmax ÷ CEC-listed area 1.63 m².

Build & dimensions

CEC PV Module List (Oct 7, 2026)

Module area1.63 m² (17.5 ft²)CEC-listed area
Cells96 cells
Back coverBlack backsheet
FrameBlack frame

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	−0.282 %/°C
Isc coefficient α	+0.035 %/°C
Operating cell temperature	NOCT 45.3 °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	240.5 W	54.54 V × 4.41 A	60.5 W	90%
350 W	240.5 W	54.54 V × 4.41 A	60.5 W	86%

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

PVEL Scorecards

Maxeon Solar Technologies named Top Performer, 2017–2025

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

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

72.3 V

Voc when cold

per panel

47.1 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	2–8
Solis (Ginlong) S6-EH1P10K-H-US	600 V	80–520 V	datasheet	2–8
Solis (Ginlong) Solis-1P7.6K-4G-US	600 V	100–500 V	datasheet	3–8
Qcells Q.VOLT H7.6SX	498 V	234–498 V	CEC test window	5–6

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	72.3 / 47.1 V	✗ Not allowed: cold Voc above max input	1.16
Enphase IQ8X-80-M-US	320–540 W	79.5 V	43–60 V	72.3 / 47.1 V	✓ Within range	0.88
APsystems (Alt Power System) DS3-L	265–570 W	60 V	28–45 V	72.3 / 47.1 V	✗ Not allowed: cold Voc above max input	0.43
Enphase IQ8M-72-2-US	260–460 W	60 V	30–45 V	72.3 / 47.1 V	✗ Not allowed: cold Voc above max input	1.03
Enphase IQ8A-72-2-US	295–500 W	60 V	32–45 V	72.3 / 47.1 V	✗ Not allowed: cold Voc above max input	0.96

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	561	11,791	6.08
Palmdale	1,835	615	12,909	6.69
Chula Vista	1,696	568	11,931	6.11
Huntington Beach	1,643	550	11,559	5.89
Riverside	1,696	568	11,931	6.21
Santa Clarita	1,724	578	12,128	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 335 W panels

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

Panel	Pmax	Efficiency	γ Pmax (CEC)	Voc, V	Isc, A	PVEL (product / brand)	SoCal permits (series)
Maxeon Solar Technologies SPR-X21-335-BLK	335 W	≈20.6%	−0.331	67.9	6.23	brand 8×	—
LONGi LR4-60HPB-335M	335 W	≈18.5%	−0.337	39.9	10.76	product 2021, 2022	193
JinkoSolar JKM335M-60HBL	335 W	≈19.9%	−0.406	40.8	10.73	brand 12× (2014–2026)	45
REC Group REC340AA	340 W	≈20.2%	−0.279	43.1	10.09	brand 9× (2016–2025)	30

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 Maxeon Solar Technologies

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

ManufacturerMaxeon Solar Technologies
Listed in CEC asMaxeon Solar Technologies Ltd.
Websitemaxeon.com
PVEL Top Performer (manufacturer)8 Scorecards (2017–2025)
Current panel series in CEC list13

Other series by SoCal permits

SPR-MAX6 · 2SPR-MAX6-xxx-BLKSPR-MAX3SPR-MAX3-xxx-BLKSPR-MAX3-xxx-BLK-RSPR-MAX3-xxx-COM

Questions & answers

How efficient is the Maxeon Solar Technologies SPR-X21-335-BLK?

Calculated from the panel area (1.63 m²): about 20.6% for the 335 W class. 335 W over 1.63 m² equals about 206 W per square meter.

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

PVWatts v8 with typical-year weather gives about 561 kWh per year per 335 W panel in Los Angeles and about 615 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 17.1% 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 2–8 panels per string (Voc at 2 °C = 72.3 V, Vmp at 74 °C cell = 47.1 V). Final design must follow the inverter manual and NEC 690.7.

Does it work with Enphase IQ8X-80-M-US microinverters?

Voltage check against the Enphase datasheet: Voc when cold 72.3 V vs max input 79.5 V; Vmp when hot 47.1 V vs MPPT low 43 V; recommended module power 320–540 W. Confirm on the microinverter maker’s compatibility list.

Has this panel been reliability-tested?

This exact series is not in published PVEL Top Performer tables; Maxeon Solar Technologies was named a Top Performer in 8 Scorecards (2017–2025).

Sources

California Energy Commission — Solar Equipment Lists, PV Module List, Inverter List (snapshot Oct 7, 2026).
JinkoSolar — datasheet THE MOST DEPENDABLE SOLAR BRAND.
JinkoSolar — manufacturer datasheet “Eagle HC 60M G2 315-335 Watt MONO PERC HALF CELL MODULE”.
Kiwa PVEL — PV Module Reliability Scorecard, Top Performer lists 2017–2025.
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 — 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).