--- title: "GCL GCL-NT12R/66GDF-605W 605W Solar Panel - Specs & Review | ComparePV" description: "GCL GCL-NT12R/66GDF-605W 605W solar panel. Specs: 22.40% efficiency, Monocrystalline cells, dimensions, warranty and temperature coefficient." source: "https://comparepv.com/panel/gcl-gcl-nt12r-66gdf-605w" updated: 2026-09-11 --- # GCL GCL-NT12R/66GDF-605W Middle of its segment, modest efficiency 1,086 panels in the segment TOPCon 600-650 W ## Identity - **Manufacturer:** GCL - **Model:** GCL-NT12R/66GDF-605W - **Series:** GCL-NT12R/66GDF (605-630W) - **Rated power:** 605 W - **Cell technology:** TOPCon - **Bifacial:** yes ## How it compares Compared against segment TOPCon 600-650 W (1086 panels). | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Power (Wp) | 605 W | 620 W | Weak - bottom 15% | | | Module efficiency | 22.40% | 22.80% | Weak - bottom 23% | 4,774 | | Power density | 224.0 | 227.7 | Weak - bottom 23% | 4,780 | | Temperature coefficient | -0.290 | -0.290 | Typical | 2,165 | | Weight (kg) | 32.5 kg | 32.7 kg | Typical | | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | ### Full peer table | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Module efficiency | 22.40% | 22.80% | Weak - bottom 23% | 4,774 | | Power density | 224.0 | 227.7 | Weak - bottom 23% | 4,780 | | Temperature coefficient | -0.290 | -0.290 | Typical | 2,165 | | Weight per kWp | 53.7 | 53.1 | Typical | 7,739 | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | ### Watch out for - **22.40% module efficiency** - Bottom 23% of the TOPCon 600-650 W segment, against a median of 22.80%. - **224.0 watts per square metre** - Bottom 23% of the TOPCon 600-650 W segment, against a median of 227.7. - **Best for:** Utility-scale and commercial. - **Not ideal for:** Tight roof space and roofs where every square metre has to count. ## Specification ### Electrical - **Rated power (Pmax):** 605 W - **Efficiency:** 22.40 % - **Voltage at Pmax (Vmp):** 40.34 V - **Current at Pmax (Imp):** 15.00 A - **Open-circuit voltage (Voc):** 47.95 V - **Short-circuit current (Isc):** 15.80 A - **Max system voltage:** 1500 V ### Temperature - **Temperature coefficient of Pmax:** -0.290 %/degC - **Temperature coefficient of Voc:** -0.250 %/degC - **Temperature coefficient of Isc:** 0.045 %/degC ### Cell and construction - **Cell type:** Monocrystalline - **Cell technology:** TOPCon - **Cell count:** 132 - **Bifacial:** yes ### Physical - **Length:** 2382 mm - **Width:** 1134 mm - **Thickness:** 30 mm - **Weight:** 32.5 kg - **Area:** 2.70 m2 - **Power density:** 224.0 Wp/m2 ### Warranty and degradation - **Product warranty:** 12 years - **Performance warranty:** 30 years - **Output guaranteed at end of warranty:** 87.4 % - **First-year degradation:** 1.00 % - **Annual degradation:** 0.40 % - **Output after 30 years:** 529 W ## Rank in the whole catalogue | Measure | Position | | --- | --- | | Efficiency | 4774 of 14005 | | Power density | 4780 of 14005 | | Temperature coefficient | 2165 of 14005 | | Weight | 7739 of 14005 | | Warranty | 21 of 14005 | ## Pros - **Low Temperature Coefficient of Power** - The Pmax temperature coefficient is -0.29%/°C — one of the lowest in the 600+ W module segment. At a typical cell operating temperature of 65°C, power loss reaches ~7.0%, while conventional PERC technology incurs ~9–10%. Actual annual energy yield in a Central European climate is therefore higher than STC nameplate figures alone would suggest. - **Efficiency at the Top of Its Segment** - The highest-performing variants in the series achieve 23.3% module efficiency — matching the Canadian Solar TOPBiHiKu6 Anti-Dust and trailing the Jinko Tiger Neo 66HL4M-BDV (23.32%) by just 0.02 percentage points. The series clearly outpaces the Leapton LP182\*199-M-72-NH (22.54%), translating to ~3.4% higher installed capacity for the same roof or field area. - **Bifacial Dual-Glass Construction with Measurable Rear-Side Yield Gain** - The glass-glass structure eliminates the rear EVA encapsulant, reducing the risk of microcracks and accelerated PID degradation. The manufacturer claims up to 30% additional energy yield from the rear surface — a figure attainable in ground-mounted utility systems installed over light-colored soil, gravel, or white roofing membranes. - **30-Year Power Output Warranty (87.4%)** - GCL guarantees retention of ≥87.4% of nominal power output after 30 years, with linear degradation of ≤0.4%/year following the first year. For infrastructure investors, this translates into a predictable revenue model over the full project financing term. - **BNEF Tier 1 Manufacturer — Bankability Confirmed** - GCL-SI appears on the Bloomberg NEF Tier 1 list (confirmed in multiple consecutive rankings; ranked #2 globally by shipment volume). This status is required by most lenders and investment funds for non-recourse financing of utility-scale projects, streamlining the debt-raising process for large PV plants. ## Cons - **Module Weight ~32.5 kg (Dual-Glass)** - The glass-glass construction raises module weight to ~32.5 kg — 3–5 kg more than comparable aluminum-framed modules (e.g., the framed Jinko Tiger Neo at ~28 kg). For flat-roof installations and carport structures, this requires structural load capacity verification and may increase balance-of-system (BoS) installation costs. - **Limited Brand Recognition in the European Market** - Despite BNEF Tier 1 status, GCL-SI has a smaller distribution footprint in Europe than Jinko Solar or Canadian Solar. Some European project finance banks and insurers may require additional due diligence documentation or apply a higher risk spread to projects using GCL modules, compared to manufacturers with a stronger local service and distribution network. ## About this series The GCL GCL-NT12R/66GDF (605-630W) series are modules designed for real-world challenges of large-scale installations - achieving maximum yield from the same surface area and reliable performance in demanding environments. These modules feature **N-type TOPCon cells**, which effectively withstand elevated temperatures and maintain high efficiency over the long term, translating to stable energy production year-round. A key advantage is the **bifacial** design - the panel can also utilize reflected light from the ground, making it easier to increase energy yield on bright grounds, gravel, or membrane roofs without adding more modules. The **dual-glass (glass-glass)** version minimizes the risk of micro-cracks and accelerated degradation, which appeals to investors focused on long-term operation and lower maintenance costs. This is a sensible choice for ground-mounted farms, carports, and commercial projects, where the **30-year power warranty** and resilience matter. ## Notable figures - Efficiency of 22.4% matches the \*\*TOPCon 600-650W\*\* median - 224.0 W/m² power density is 3.7 W/m² below \*\*TOPCon 600-650W\*\* median (227.7 W/m²) - requires larger installation area - Temperature coefficient of -0.29%/°C matches the \*\*TOPCon 600-650W\*\* median - Bifaciality factor of 80% can add 4-12% extra yield with reflective mounting surface - In the top 34% for efficiency among all TOPCon panels ## Questions ### What is the efficiency of the GCL-NT12R/66GDF panels and what does it mean in practice? The GCL-NT12R/66GDF series modules achieve an efficiency range of 22.4–23.3% thanks to N-type TOPCon cells. In practical terms, a single panel (approx. 2.70 m²) delivers up to 630 W of peak power — significantly more than older PERC modules of comparable dimensions. This is particularly relevant for space-constrained applications such as utility-scale farms and carports, where every square meter of available area directly impacts system output. ### What warranty is provided for the GCL-NT12R/66GDF panels and what does it cover? GCL offers two distinct warranties: a 12-year product warranty covering material and workmanship defects, and a 30-year linear power output warranty guaranteeing at least 87.4% of nominal power at the end of the warranty period. The 30-year power warranty is a compelling proposition for investors planning long-term operation of utility-scale ground-mounted plants or commercial installations, as it reduces financial risk over the project's full lifecycle. ### Are the GCL-NT12R/66GDF panels bifacial, and when does bifaciality actually pay off? Yes, the GCL-NT12R/66GDF series features a bifacial design — the rear side of the module generates additional energy by capturing irradiance reflected from the ground surface. The technology delivers measurable gains when deployed over high-albedo surfaces such as white gravel ballast, light-colored roofing membranes, or snow cover. On ground-mounted systems with appropriate ground albedo, rear-side energy yield can contribute several to over ten percent of additional annual production, depending on site conditions and mounting height. ### What are the dimensions and weight of the GCL-NT12R/66GDF panel — can it be installed on a residential rooftop? The panel measures 2382×1134×30 mm and weighs approximately 32.5 kg, a result of its dual-glass (glass-glass) construction rather than a conventional polymer backsheet. This is a large-format module designed primarily for ground-mounted farms, carports, and large commercial installations. Rooftop installation on a single-family home is technically feasible; however, it requires a robust mounting structure and should be preceded by a structural load assessment of the roof carried out by a qualified installer. ### How do the GCL-NT12R/66GDF panels perform at high temperatures during summer? The N-type TOPCon cells used in the GCL-NT12R/66GDF series have a power temperature coefficient of -0.29%/°C — superior to typical PERC modules, which range from -0.34% to -0.36%/°C. This means that at a cell operating temperature of 65°C, power loss is approximately 13%, compared to 15–16% with older technologies. Over the long term, particularly in warm climates or on highly irradiated roof planes, this lower temperature sensitivity translates into meaningfully higher annual energy yield. ### Is GCL a reliable manufacturer and how can I be confident in the quality of the NT12R/66GDF panels? GCL (GCL System Integration) is a Chinese manufacturer classified as Tier 1 by independent industry rating agencies, which confirms its bankability — banks and investment funds accept these modules as collateral for PV project financing. The company is one of the world's largest suppliers of solar cells and modules. The NT12R/66GDF series carries the standard certifications required by European investors and insurers, including IEC 61215 and IEC 61730, validating both performance and safety. ## Datasheet [Manufacturer datasheet (PDF)](https://comparepv.com/datasheets/en-nt12r66gdf-j1-00b01e073b8a.pdf) ## Alternatives | Panel | Power | How it differs | | --- | --- | --- | | [AIKO AIKO-A650-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a650-mae72mw) | 650 W | +45 W, lighter, +2.8 pp | | [AIKO AIKO-A645-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a645-mae72mw) | 645 W | +40 W, lighter, +2.6 pp | | [Longi Solar LR7-60HVH-560M](https://comparepv.com/panel/longi-lr7-60hvh-560m) | 560 W | -45 W, lighter, +2.4 pp | | [AIKO AIKO-A640-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a640-mae72mw) | 640 W | +35 W, lighter, +2.4 pp | | [Longi Solar LR7-60HVH-555M](https://comparepv.com/panel/longi-lr7-60hvh-555m) | 555 W | -50 W, lighter, +2.2 pp | | [AIKO AIKO-A635-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a635-mae72mw) | 635 W | +30 W, lighter, +2.2 pp | | [GCL GCL-NT12R/66GDF-610W](https://comparepv.com/panel/gcl-gcl-nt12r-66gdf-610w) | 610 W | +0.2 pp | | [GCL GCL-NT12R/66GDF-615W](https://comparepv.com/panel/gcl-gcl-nt12r-66gdf-615w) | 615 W | +10 W, +0.4 pp | | [GCL GCL-NT12R/66GDF-620W](https://comparepv.com/panel/gcl-gcl-nt12r-66gdf-620w) | 620 W | +15 W, +0.6 pp | | [GCL GCL-NT12R/66GDF-625W](https://comparepv.com/panel/gcl-gcl-nt12r-66gdf-625w) | 625 W | +20 W, +0.7 pp | | [AIKO AIKO-A680-MDE72Mw](https://comparepv.com/panel/aiko-aiko-a680-mde72mw) | 680 W | +75 W, lighter, +2.8 pp | | [AIKO AIKO-A675-MDE72Mw](https://comparepv.com/panel/aiko-aiko-a675-mde72mw) | 675 W | +70 W, lighter, +2.6 pp | | [AIKO AIKO-A700-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a700-mae78dw) | 700 W | +95 W, cooler, +2.6 pp | | [AIKO AIKO-A695-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a695-mae78dw) | 695 W | +90 W, cooler, +2.5 pp | | [AIKO AIKO-G670-MCH72Mw](https://comparepv.com/panel/aiko-aiko-g670-mch72mw) | 670 W | +65 W, lighter, +2.4 pp | | [Longi Solar LR7-72HVHF-670M](https://comparepv.com/panel/longi-lr7-72hvhf-670m) | 670 W | +65 W, lighter, +2.4 pp | --- Source: https://comparepv.com/panel/gcl-gcl-nt12r-66gdf-605w Not in this file, on the page: a thirty-year output simulator, a bifacial gain calculator and alternatives filtered by how closely they match these dimensions.