--- title: "Canadian Solar CS3U-355P 355W Solar Panel - Specs & Review | ComparePV" description: "Canadian Solar CS3U-355P 355W solar panel. Specs: 17.90% efficiency, Polycrystalline cells, dimensions, warranty and temperature coefficient." source: "https://comparepv.com/panel/canadian-solar-cs3u-355p" updated: 2026-09-11 --- # Canadian Solar CS3U-355P Middle of its segment, modest efficiency 579 panels in the segment PERC 350-400 W ## Identity - **Manufacturer:** Canadian Solar - **Model:** CS3U-355P - **Series:** KuMax - **Rated power:** 355 W - **Cell technology:** PERC ## How it compares Compared against segment PERC 350-400 W (579 panels). | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Power (Wp) | 355 W | 380 W | Weak - bottom 7% | | | Module efficiency | 17.90% | 19.90% | Weak - bottom 4% | 13,249 | | Power density | 178.9 | 199.0 | Weak - bottom 4% | 13,242 | | Temperature coefficient | -0.360 | -0.350 | Typical | 12,345 | | Weight (kg) | 22.5 kg | 21.4 kg | Weak - bottom 15% | | | Performance warranty | 25 yrs | 25 yrs | Typical | 9,798 | ### Full peer table | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Module efficiency | 17.90% | 19.90% | Weak - bottom 4% | 13,249 | | Power density | 178.9 | 199.0 | Weak - bottom 4% | 13,242 | | Temperature coefficient | -0.360 | -0.350 | Typical | 12,345 | | Weight per kWp | 63.4 | 55.8 | Weak - bottom 15% | 12,890 | | Performance warranty | 25 yrs | 25 yrs | Typical | 9,798 | ### Watch out for - **17.90% module efficiency** - Bottom 4% of the PERC 350-400 W segment, against a median of 19.90%. Ranked 13,249th in the whole database. - **178.9 watts per square metre** - Bottom 4% of the PERC 350-400 W segment, against a median of 199.0. Ranked 13,242nd in the whole database. - **63.4 kg per kWp** - Bottom 15% of the PERC 350-400 W segment, against a median of 55.8. - **Best for:** Residential, commercial, shaded-installations and cold-climate. - **Not ideal for:** Tight roof space, roofs where every square metre has to count and weight-limited structures. ## Specification ### Electrical - **Rated power (Pmax):** 355 W - **Efficiency:** 17.90 % - **Voltage at Pmax (Vmp):** 39.40 V - **Current at Pmax (Imp):** 9.02 A - **Open-circuit voltage (Voc):** 46.80 V - **Short-circuit current (Isc):** 9.59 A - **Max system voltage:** 1500 V ### Temperature - **Temperature coefficient of Pmax:** -0.360 %/degC - **Temperature coefficient of Voc:** -0.280 %/degC - **Temperature coefficient of Isc:** 0.050 %/degC - **NOCT:** 42 degC ### Cell and construction - **Cell type:** Polycrystalline - **Cell technology:** PERC - **Cell count:** 144 ### Physical - **Length:** 2000 mm - **Width:** 992 mm - **Thickness:** 35 mm - **Weight:** 22.5 kg - **Area:** 1.98 m2 - **Power density:** 178.9 Wp/m2 ### Warranty and degradation - **Product warranty:** 12 years - **Performance warranty:** 25 years ## Rank in the whole catalogue | Measure | Position | | --- | --- | | Efficiency | 13249 of 14005 | | Power density | 13242 of 14005 | | Temperature coefficient | 12345 of 14005 | | Weight | 12890 of 14005 | | Warranty | 9798 of 14005 | ## Pros - **Half-cut cells with multi-busbar design** - The combination of half-cut PERC cells with a multi-busbar interconnection reduces resistive losses and significantly mitigates the impact of micro-cracks and partial shading on module output, which is particularly valuable for rooftop installations with partial shading from chimneys or antennas. - **Low temperature coefficient** - A power temperature coefficient of -0.36%/°C combined with a low NMOT of 42±3°C means a smaller output drop on hot days compared to typical PERC panels (usually -0.38% to -0.41%/°C), translating into higher summer energy yield. - **Reinforced frame - high mechanical resistance** - KuMax panels are certified for snow loads up to 5400 Pa and wind loads up to 3600 Pa, well above standard industry values (typically 2400 Pa/5400 Pa for many competing modules), making them a solid choice for high-snowfall regions. - **Tier-1, bankable manufacturer since 2001** - Canadian Solar is a Tier-1 manufacturer with over 20 years of market presence, ensuring project bankability for installations using this series and lower risk for institutional investors and financing banks. - **100% EL testing and PID resistance** - Every panel undergoes 100% electroluminescence (EL) testing, and PID (Potential Induced Degradation) resistance ensures stable power parameters throughout the module's operational life, minimizing the risk of hidden factory defects. ## Cons - **Production discontinued** - The KuMax series was discontinued in 2022 after 5 years on the market (launched in 2017), meaning limited availability of replacement parts and the need to source compatible substitutes in case of warranty claims or damage to individual modules in an existing installation. - **Efficiency below segment leader** - The maximum efficiency of 20.2% is lower than the competing Heliene 108HC M10 SL All Black (20.5% at the same 400 Wp rating), meaning slightly lower power yield per roof area for space-constrained installations. - **12-year product warranty below current standards** - The 12-year product warranty is shorter than what many Tier-1 manufacturers now offer (15-25 years for newer N-type/TOPCon series), a meaningful factor when comparing against currently available alternatives on the market. - **PERC technology without bifacial option** - The series is based exclusively on PERC technology without a bifacial option, missing out on the additional energy yield from ground-reflected light available in the manufacturer's newer TOPCon/HJT series. ## About this series The KuMax series from Canadian Solar is a proven solution for rooftop and ground-mount installations where the balance between price and reliability matters most. The panels use monocrystalline PERC cells in a **half-cut** configuration with a **multi-busbar design**, which reduces resistive losses and improves resistance to microcracks and partial shading. Thanks to low internal current technology, the modules maintain stable output even under weaker irradiance conditions, translating into real gains in annual energy yield. KuMax stands out with its **reinforced frame** of increased thickness, engineered for installations exposed to heavy snow and wind loads - making it an attractive option for sites in more demanding climates. Production includes rigorous component testing and **100 percent EL testing** of every panel, minimizing the risk of factory defects. The panels also feature **PID resistance**, ensuring stable performance throughout the entire service life. The KuMax series works well both in residential prosumer installations and commercial PV farm projects, wherever predictable LCOE and long-term investment durability are priorities. ## Notable figures - Efficiency of 17.9% is 1.6pp below the \*\*PERC 0-400W\*\* median (19.4%) - 178.9 W/m² power density is 15.5 W/m² below \*\*PERC 0-400W\*\* median (194.4 W/m²) - requires larger installation area - Temperature coefficient of -0.36%/°C matches the \*\*PERC 0-400W\*\* median - At 22.5 kg (2.0 kg above \*\*PERC 0-400W\*\* median of 20.5 kg), requires checking roof load capacity - In the top 95% for efficiency among all PERC panels ## Questions ### Are Canadian Solar KuMax panels still available for purchase? The KuMax series has been discontinued from Canadian Solar's current production lineup and replaced by newer models, including TOPCon-based panels. Units may still be found in distributor stock or as remaining inventory, so it's worth confirming current availability with your supplier and verifying that the manufacturer's warranty is still fully honored despite the series being discontinued. ### What warranty comes with KuMax panels and what does it cover? Canadian Solar provides a 12-year product warranty covering material and workmanship defects, plus a 25-year power performance warranty. This means the manufacturer guarantees a defined level of energy output over a quarter century, which is a standard benchmark for Tier 1 panels in this class. ### How do half-cut cells in KuMax differ from standard PERC panels? The half-cut cells in KuMax are standard monocrystalline PERC cells cut in half, reducing current losses and internal resistance in the module. Combined with the multi-busbar design, this improves resistance to microcracks and partial shading, such as from chimneys or antennas, and increases overall energy yield compared to classic full-cell panels of the same power rating. ### Is the 400 Wp KuMax panel suitable for installations with heavy snow and wind loads? Yes, this is one of the key advantages of the KuMax series. The panels feature a reinforced, thicker frame specifically engineered for increased mechanical loads, making them a good choice for rooftops in mountainous regions or other areas with heavy snowfall and strong winds. ### Are KuMax panels resistant to PID degradation? Yes, KuMax modules carry certified PID (Potential Induced Degradation) resistance, addressing power loss caused by voltage potential differences within an array. This keeps electrical parameters stable throughout the panel's service life, even in large installations with high system voltages. ### Is it worth buying KuMax panels for commercial or utility-scale projects despite the end of production? KuMax panels remain a solid choice for commercial projects thanks to predictable LCOE, 100% EL testing of every unit, and Canadian Solar's reputation as a Tier 1 manufacturer. When purchasing remaining stock, however, it's important to confirm batch consistency in production date and specifications, since new units of this series are no longer being manufactured. ## Datasheet [Manufacturer datasheet (PDF)](https://comparepv.com/datasheets/Canadian_Solar-Datasheet-KuMax_CS3U-P_EN-42bdaefa0f89.pdf) ## Alternatives | Panel | Power | How it differs | | --- | --- | --- | | [SunLink LNSK-340M](https://comparepv.com/panel/sunlink-lnsk-340m) | 340 W | -15 W, lighter, +2.2 pp | | [SunLink LNSU-405M](https://comparepv.com/panel/sunlink-lnsu-405m) | 405 W | +50 W, heavier, +2.2 pp | | [Canadian Solar CS3K-330P](https://comparepv.com/panel/canadian-solar-cs3k-330p) | 330 W | -25 W, lighter, +2.0 pp | | [Canadian Solar CS3K-335MB-AG](https://comparepv.com/panel/canadian-solar-cs3k-335mb-ag) | 335 W | -20 W, +2.0 pp, +5 yr warranty | | [Canadian Solar CS3U-395P](https://comparepv.com/panel/canadian-solar-cs3u-395p) | 395 W | +40 W, +2.0 pp | | [SunLink LNSU-400M](https://comparepv.com/panel/sunlink-lnsu-400m) | 400 W | +45 W, heavier, +1.9 pp | | [SunLink LNSK-335M](https://comparepv.com/panel/sunlink-lnsk-335m) | 335 W | -20 W, lighter, +1.9 pp | | [Sunlike Solar LNSF-400M](https://comparepv.com/panel/sunlike-solar-lnsf-400m) | 400 W | +45 W, heavier, +1.9 pp | | [Canadian Solar CS3U-360P](https://comparepv.com/panel/canadian-solar-cs3u-360p) | 360 W | +0.3 pp | | [Canadian Solar CS3U-365P](https://comparepv.com/panel/canadian-solar-cs3u-365p) | 365 W | +10 W, +0.5 pp | | [Canadian Solar CS3U-370P](https://comparepv.com/panel/canadian-solar-cs3u-370p) | 370 W | +15 W, +0.8 pp | | [Canadian Solar CS3U-375P](https://comparepv.com/panel/canadian-solar-cs3u-375p) | 375 W | +20 W, +1.0 pp | | [Maxeon SPR-MAX7-475](https://comparepv.com/panel/maxeon-spr-max7-475) | 475 W | +120 W, +6.1 pp, +15 yr warranty | | [Maxeon SPR-MAX7-470](https://comparepv.com/panel/maxeon-spr-max7-470) | 470 W | +115 W, +5.8 pp, +15 yr warranty | | [Maxeon SPR-MAX7-465](https://comparepv.com/panel/maxeon-spr-max7-465) | 465 W | +110 W, +5.6 pp, +15 yr warranty | | [JA Solar NS-420MH-80](https://comparepv.com/panel/ja-solar-ns-420mh-80) | 420 W | +65 W, cooler, +4.4 pp | --- Source: https://comparepv.com/panel/canadian-solar-cs3u-355p Not in this file, on the page: a thirty-year output simulator and alternatives filtered by how closely they match these dimensions.