X-21 Series Solar Panel
More than 21% Efficiency
Ideal for roofs where space is at a premium or where future expansion might be needed.
Maximum Performance
Designed to deliver the most energy in demanding real-world conditions, in partial shade and hot rooftop temperatures.1,2,4
Premium Aesthetics
SunPower® Signature Black X-Series panels blend harmoniously into your roof. The most elegant choice for your home.
Engineered for Peace of Mind
Designed to deliver consistent, trouble-free energy over a very long lifetime. 3,4
Designed for Durability
The SunPower Maxeon Solar Cell is the only cell built on a solid copper foundation. Virtually impervious to the corrosion and cracking that degrade conventional panels. 3
Same excellent durability as E-Series panels. #1 Rank in Fraunhofer durability test.9 100% power maintained in Atlas 25+ comprehensive durability test.10
Highest Efficiency5
Generate more energy per square foot
X-Series residential panels convert more sunlight to electricity by producing 38% more power per panel1 and 70% more energy per square foot over 25 years.1,2,3
Highest Energy Production6
Produce more energy per rated watt
High year-one performance delivers 8–10% more energy per rated watt.2 This advantage increases over time, producing 21% more energy over the first 25 years to meet your needs.3
Electrical Data
Nominal Power (Pnom)11 345 W
Power Tolerance +5/–0%
Avg. Panel Efficiency12 21.5%
Rated Voltage (Vmpp) 57.3 V
Rated Current (Impp) 6.02 A
Open-Circuit Voltage (Voc) 68.2 V
Short-Circuit Current (Isc) 6.39 A
Max. System Voltage 600 V UL & 1000 V IEC
Maximum Series Fuse 15 A
Power Temp Coef. –0.29% / o C
Voltage Temp Coef. –167.4 mV / o C
Current Temp Coef. 2.9 mA / o C
References:
  • All comparisons are SPR-X21-345 vs. a representative conventional panel: 250 W, approx. 1.6 m², 15.3% efficiency.
  • Typically 8–10% more energy per watt, BEW/DNV Engineering “SunPower Yield Report,” Jan 2013.
  • Specifically 8-10% extra energy per watt, BEW/DNV Technology " Yield Report," Jan 2013, with CFV Solar Test Lab Report #12063, Jan 2013 temp. coef. computation.
  • SunPower 0.25%/yr degradation vs. 1.0%/yr conv. panel. Campeau, Z. et al. “SunPower Module Degradation Rate,” SunPower white paper, Feb 2013; Jordan, Dirk “SunPower Test Report,” NREL, Q1-2015.
  • “SunPower Module 40-Year Useful Life” SunPower white paper, May 2015. Useful life is 99 out of 100 panels operating at more than 70% of rated power.
  • Highest of over 3,200 silicon solar panels, Photon Module Survey, Feb 2014.
  • 1% more energy than E-Series panels, 8% more energy than the average of the top 10 panel companies tested in 2012 (151 panels, 102 companies), Photon International, Feb 2013.
  • Compared with the top 15 manufacturers. SunPower Warranty Review, May 2015.
  • Some restrictions and exclusions may apply. See warranty for details.
  • X-Series same as E-Series, 5 of top 8 panel manufacturers tested in 2013 report, 3 additional panels in 2014. Ferrara, C., et al. "Fraunhofer PV Durability Initiative for Solar Modules: Part 2". Photovoltaics International, 2014.
  • Compared with the non-stress-tested control panel. X-Series same as E-Series, tested in Atlas 25+ Durability test report, Feb 2013.
  • Standard Test Conditions (1000 W/m² irradiance, AM 1.5, 25° C). NREL calibration Standard: SOMS current, LACCS FF and Voltage.
  • Based on average of measured power values during production.
  • Type 2 fire rating per UL1703:2013, Class C fire rating per UL1703:2002.
  • See salesperson for details.
Tests and Certifications
Standard Tests13 UL 1703, IEC 61215, IEC 61730
Quality Certs ISO 9001:2008, ISO 14001 :2004
EHS Compliance RoHS, OHSAS 18001:2007, lead free, REACH SVHC-163, PV Cycle
Sustainability Cradle to Cradle CertifiedTM Silver (eligible for LEED points)14
Ammonia Test IEC 62716
Desert Test 10.1109/PVSC.2013.6744437
Salt Spray Test IEC 61701 (maximum severity)
PID Test Potential-Induced Degradation free: 1000 V9
Available Listings UL, TUV, JET, MCS, CSA, FSEC, CEC
Operating Condition And Mechanical Data
Temperature –40° F to +185° F (–40° C to +85° C)
Impact Resistance 1 inch (25 mm) diameter hail at 52 mph (23 m/s)
Appearance Class A+
Solar Cells 96 Monocrystalline Maxeon Gen III
Tempered Glass High-transmission tempered anti-reflective
Junction Box IP-65, MC4 compatible
Weight 41 lbs (18.6 kg)
Max. Load G5 Frame: Wind: 62 psf, 3000 Pa front & back Snow: 125 psf, 6000 Pa front
G3 Frame: Wind: 50 psf, 2400 Pa front & back Snow: 112 psf, 5400 Pa front
Frame Class 1 black anodized (highest AAMA rating)