--- title: "GCL NT12R/66GDF-650W 650W Solar Panel - Specs & Review | ComparePV" description: "GCL NT12R/66GDF-650W 650W solar panel. Specs: 24.06% efficiency, Monocrystalline cells, dimensions, warranty and temperature coefficient." source: "https://comparepv.com/panel/gcl-nt12r-66gdf-650w" updated: 2026-09-11 --- # GCL NT12R/66GDF-650W Space saver, no clear weak spot 249 panels in the segment TOPCon 650-700 W ## Identity - **Manufacturer:** GCL - **Model:** NT12R/66GDF-650W - **Series:** NT12R/66GDF - **Rated power:** 650 W - **Cell technology:** TOPCon - **Bifacial:** yes ## How it compares Compared against segment TOPCon 650-700 W (249 panels). | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Power (Wp) | 650 W | 665 W | Weak - bottom 13% | | | Module efficiency | 24.06% | 22.40% | Strong - top 21% | 268 | | Power density | 240.6 | 223.7 | Strong - top 18% | 233 | | Temperature coefficient | -0.290 | -0.290 | Typical | 2,165 | | Weight (kg) | 32.5 kg | 34.6 kg | Typical | | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | ### Full peer table | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Module efficiency | 24.06% | 22.40% | Strong - top 21% | 268 | | Power density | 240.6 | 223.7 | Strong - top 18% | 233 | | Temperature coefficient | -0.290 | -0.290 | Typical | 2,165 | | Weight per kWp | 50.0 | 53.2 | Typical | 3,317 | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | ### Strengths - **240.6 watts per square metre** - Top 18% of the TOPCon 650-700 W segment, against a median of 223.7. - **24.06% module efficiency** - Top 21% of the TOPCon 650-700 W segment, against a median of 22.40%. - **Best for:** Utility-scale, commercial and hot-climate. ## Specification ### Electrical - **Rated power (Pmax):** 650 W - **Efficiency:** 24.06 % - **Voltage at Pmax (Vmp):** 42.15 V - **Current at Pmax (Imp):** 15.42 A - **Open-circuit voltage (Voc):** 49.65 V - **Short-circuit current (Isc):** 16.25 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:** 240.6 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:** 568 W ## Rank in the whole catalogue | Measure | Position | | --- | --- | | Efficiency | 268 of 14005 | | Power density | 233 of 14005 | | Temperature coefficient | 2165 of 14005 | | Weight | 3317 of 14005 | | Warranty | 21 of 14005 | ## Pros - **Peak Efficiency of 24.06% — Segment Leader** - The top variant in the series achieves 24.06% efficiency, matching the Jinko Solar Tiger Neo 66HL4M-BDX (24.06%) and clearly outperforming the Astronergy ASTRO N5 (23.3%) and BYD AURO N NLBK-39 (23.25%). For ground-mounted installations, this translates into meaningfully higher energy yield without increasing the module count. - **Low Temperature Coefficient (−0.29%/°C)** - The Pmax temperature coefficient of −0.29%/°C is competitive even within the N-type TOPCon class and significantly better than typical PERC modules (~−0.35%/°C). At a cell temperature of 65°C — representative of a summer day on a Polish ground-mounted farm — power loss is approximately 11.6% versus ~14% for PERC, a difference that directly impacts annual energy yield. - **Bifacial Dual-Glass Construction with Up to 30% Rear-Side Gain** - The dual-glass design eliminates EVA encapsulant yellowing degradation, reduces LETID associated with older cell technologies, and improves mechanical durability. In ground-mounted systems over light-colored or gravel surfaces, bifaciality realistically adds 8–15% to annual energy production, directly lowering the project's LCOE. - **30-Year Power Warranty (≥87.4%) from a Tier 1 BNEF Manufacturer** - GCL-SI appears on the Bloomberg NEF Tier 1 list, meeting the tightened 2025 requirement of ≥6 projects >10 MW financed by independent commercial banks within the preceding 24 months. The 30-year linear power warranty with a floor of ≥87.4% of nominal power is a prerequisite for non-recourse project financing and protects LCOE over the full asset lifetime. - **GCL Group Vertical Integration from Polysilicon to Module** - GCL Group controls the entire value chain: FBR polysilicon production (proprietary granular technology), G12R wafer manufacturing, N-type TOPCon cell fabrication (Wuhu facility, 20 GW), and module assembly (~30 GW/year nameplate capacity as of 2023). Full vertical integration eliminates supply disruption risk and ensures consistent quality — a material advantage for large-scale ground-mounted EPC contracts. ## Cons - **Lower-Wattage Variants Fall Below Peer Median** - The 610–625 W variants in this series deliver 22.6–22.95% efficiency, placing them below the baseline efficiency of the Astronergy ASTRO N5 (23.3%) and BYD AURO N NLBK-39 (23.25%). Investors selecting lower power classes from the NT12R/66GDF series will not gain a clear N-type efficiency advantage over these competitors and should conduct a direct variant-to-variant comparison before making a final procurement decision. ## About this series The GCL NT12R/66GDF solar panel series is an advanced solution based on **N-type TOPCon cell technology**, which redefines performance standards in challenging lighting conditions. Thanks to the **bifacial dual-glass** design, these modules not only generate additional energy from both sides but also demonstrate significantly higher resistance to light-induced degradation and external factors. The use of rectangular silicon cells allows for maximum utilization of the module surface, translating into higher power density while maintaining optimal mounting dimensions. This is an ideal proposition for investors seeking financial stability for their projects, as low annual degradation guarantees higher yields over a span of several decades. GCL NT12R/66GDF eliminates the problem of rapid efficiency loss, offering an **excellent temperature coefficient**, which is crucial during hot days on Polish solar farms. This product is primarily dedicated to large-scale ground-mounted installations and demanding commercial systems where the **lowest levelized cost of energy** (LCOE) is what counts. It stands out from the competition due to its **exceptional mechanical resistance** and precise fit for modern solar tracking systems, making it one of the most future-proof components currently available on the PV market. ## Notable figures - At 24.1% efficiency, this panel is 1.7pp above typical \*\*TOPCon 650-700W\*\* modules (median: 22.4%) - Power density of 240.6 W/m² packs 16.9 W/m² more into the same footprint vs \*\*TOPCon 650-700W\*\* median (223.7 W/m²) - At -0.29%/°C, hot weather performance is typical for \*\*TOPCon 650-700W\*\* panels - Weight of 32.5 kg (2.1 kg below \*\*TOPCon 650-700W\*\* median of 34.6 kg) allows easier transport and roof mounting - Bifaciality factor of 80% can add 4-12% extra yield with reflective mounting surface ## Questions ### What is the warranty coverage for the GCL NT12R/66GDF panels? The GCL NT12R/66GDF series comes with a 12-year product warranty (materials and workmanship) and a 30-year linear power output warranty. After 30 years of operation, modules retain at least 87.4% of their nominal power output. This is one of the longest warranty packages available on the market, which directly contributes to the financial security of a project and a lower LCOE over the entire system lifetime. ### Are the GCL NT12R/66GDF panels suitable for large-scale solar farms and tracker systems? Yes, the NT12R/66GDF series is designed primarily for utility-scale ground-mounted installations. The module format of 2382×1134×30 mm and a high unit power output of up to 650 Wp reduce the number of modules required per MW, thereby lowering balance-of-system (BoS) and installation costs. Tight dimensional tolerances and a reinforced dual-glass construction ensure full compatibility with modern solar tracking systems, including single-axis and dual-axis trackers. ### What does N-type TOPCon technology mean in the GCL NT12R/66GDF panels, and is the premium price justified? TOPCon (Tunnel Oxide Passivated Contact) is an N-type silicon cell architecture featuring a thin tunnel oxide layer that significantly reduces charge carrier recombination. In practice, this translates to higher module efficiency (up to 23.3%) and an annual degradation rate noticeably lower than that of conventional P-type PERC cells. For a system operating over 25–30 years, the cumulative energy yield difference is measurable and typically justifies the higher upfront cost. ### How does the bifacial design of the GCL NT12R/66GDF affect energy yield in Poland? The bifacial dual-glass construction allows the rear side of the panel to absorb irradiance reflected from the ground surface (albedo). With highly reflective ground covers such as sand, light-colored geomembranes, or snow, the rear side can contribute an additional 10–25% of energy relative to a standard monofacial module. Under Polish climatic conditions — particularly in winter with snow cover — this effect is clearly measurable and improves the annual energy yield. ### Do the GCL NT12R/66GDF panels perform well on hot days? Yes. The temperature coefficient of the NT12R/66GDF series is approximately -0.29%/°C, which is among the best figures available on the market for modules in this class. By comparison, older P-type cells typically reach -0.35%/°C or higher. In practical terms, at a module operating temperature of 70°C, power losses are several percentage points lower than those of lower-cost competing products — a factor of meaningful significance for Polish solar farms during summer months. ### How much does a GCL NT12R/66GDF panel weigh, and does it require a specialized mounting structure? The GCL NT12R/66GDF module weighs approximately 32.5 kg, which is a direct result of using tempered glass on both the front and rear surfaces (dual-glass construction). This is substantially heavier than standard backsheet modules. Before procurement, the load-bearing capacity of the rooftop or ground-mounted structure must be verified, as the difference in total installation mass can be significant for a typical solar farm. Consultation with a structural engineer is strongly recommended. ## Datasheet [Manufacturer datasheet (PDF)](https://comparepv.com/datasheets/EN-NT12R66GDF_20-J2-b5876bb99218.pdf) ## Alternatives | Panel | Power | How it differs | | --- | --- | --- | | [AIKO AIKO-A650-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a650-mae72mw) | 650 W | Cooler, lighter, +1.1 pp | | [AIKO AIKO-A680-MDE72Mw](https://comparepv.com/panel/aiko-aiko-a680-mde72mw) | 680 W | +30 W, lighter, +1.1 pp | | [AIKO AIKO-A675-MDE72Mw](https://comparepv.com/panel/aiko-aiko-a675-mde72mw) | 675 W | Cooler, lighter, +0.9 pp | | [AIKO AIKO-A645-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a645-mae72mw) | 645 W | Cooler, lighter, +0.9 pp | | [AIKO AIKO-A700-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a700-mae78dw) | 700 W | +50 W, cooler, +0.9 pp | | [AIKO AIKO-A695-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a695-mae78dw) | 695 W | +45 W, cooler, +0.8 pp | | [AIKO AIKO-G670-MCH72Mw](https://comparepv.com/panel/aiko-aiko-g670-mch72mw) | 670 W | Cooler, lighter, +0.7 pp | | [GCL GCL-NT12R/66GDF-605W](https://comparepv.com/panel/gcl-gcl-nt12r-66gdf-605w) | 605 W | -45 W, -1.7 pp | | [GCL GCL-NT12R/66GDF-610W](https://comparepv.com/panel/gcl-gcl-nt12r-66gdf-610w) | 610 W | -40 W, -1.5 pp | | [GCL GCL-NT12R/66GDF-615W](https://comparepv.com/panel/gcl-gcl-nt12r-66gdf-615w) | 615 W | -35 W, -1.3 pp | | [GCL GCL-NT12R/66GDF-620W](https://comparepv.com/panel/gcl-gcl-nt12r-66gdf-620w) | 620 W | -30 W, -1.1 pp | | [GCL GCL-NT12R/66GDF-625W](https://comparepv.com/panel/gcl-gcl-nt12r-66gdf-625w) | 625 W | -25 W, -1.0 pp | | [Longi Solar LR7-72HVHF-670M](https://comparepv.com/panel/longi-lr7-72hvhf-670m) | 670 W | Cooler, lighter, +0.7 pp | | [Jinko Solar JKM650-670N-66QL6-BDV (670W class)](https://comparepv.com/panel/jinko-solar-jkm650-670n-66ql6-bdv-670w-class) | 670 W | +20 W, cooler, +0.7 pp | --- Source: https://comparepv.com/panel/gcl-nt12r-66gdf-650w Not in this file, on the page: the I-V and temperature curves lifted from the manufacturer's datasheet, a thirty-year output simulator, a bifacial gain calculator and alternatives filtered by how closely they match these dimensions.