--- title: "GCL GCL-NT12/66GDF 725 725W Solar Panel - Specs & Review | ComparePV" description: "GCL GCL-NT12/66GDF 725 725W solar panel. Specs: 23.34% efficiency, Monocrystalline cells, dimensions, warranty and temperature coefficient." source: "https://comparepv.com/panel/gcl-gcl-nt12-66gdf-725-1" updated: 2026-09-11 --- # GCL GCL-NT12/66GDF 725 Efficiency leader, no clear weak spot 420 panels in the segment TOPCon 700-750 W ## Identity - **Manufacturer:** GCL - **Model:** GCL-NT12/66GDF 725 - **Series:** GCL-NT12/66GDF - **Rated power:** 725 W - **Cell technology:** TOPCon - **Bifacial:** yes ## How it compares Compared against segment TOPCon 700-750 W (420 panels). | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Power (Wp) | 725 W | 715 W | Strong - top 17% | | | Module efficiency | 23.34% | 23.00% | Strong - top 15% | 943 | | Power density | 233.4 | 230.2 | Strong - top 18% | 936 | | Temperature coefficient | -0.290 | -0.290 | Typical | 2,165 | | Weight (kg) | 38.3 kg | 38.0 kg | Typical | | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | ### Full peer table | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Module efficiency | 23.34% | 23.00% | Strong - top 15% | 943 | | Power density | 233.4 | 230.2 | Strong - top 18% | 936 | | Temperature coefficient | -0.290 | -0.290 | Typical | 2,165 | | Weight per kWp | 52.8 | 52.9 | Typical | 6,514 | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | ### Strengths - **23.34% module efficiency** - Top 15% of the TOPCon 700-750 W segment, against a median of 23.00%. - **233.4 watts per square metre** - Top 18% of the TOPCon 700-750 W segment, against a median of 230.2. - **Best for:** Utility-scale, commercial and hot-climate. ## Specification ### Electrical - **Rated power (Pmax):** 725 W - **Efficiency:** 23.34 % - **Voltage at Pmax (Vmp):** 41.03 V - **Current at Pmax (Imp):** 17.67 A - **Open-circuit voltage (Voc):** 48.80 V - **Short-circuit current (Isc):** 18.60 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:** 2384 mm - **Width:** 1303 mm - **Thickness:** 33 mm - **Weight:** 38.3 kg - **Area:** 3.11 m2 - **Power density:** 233.4 Wp/m2 ### Warranty and degradation - **Product warranty:** 12 years - **Performance warranty:** 30 years ## Rank in the whole catalogue | Measure | Position | | --- | --- | | Efficiency | 943 of 14005 | | Power density | 936 of 14005 | | Temperature coefficient | 2165 of 14005 | | Weight | 6514 of 14005 | | Warranty | 21 of 14005 | ## Pros - **Up to 23.5% Efficiency — Top of the Segment** - The 730 Wp variant achieves 23.5% module efficiency, placing the series on par with its direct competitors (HY Solar N-Type TOPCon, Waaree Plexus HJT, PolyCrown Mono132 — all at 23.5% maximum). The lower end of the series (22.7% at 705 Wp) still exceeds the typical premium threshold for large-format modules as of 2022 (~22.0%). - **N-Type TOPCon: Low Temperature Coefficient** - The datasheet confirms a Pmax temperature coefficient of -0.29%/°C, which translates to approximately 17% lower power losses at a module surface temperature of 70°C compared to PERC modules (~-0.35%/°C). This results in meaningfully higher annual energy yield in utility-scale installations operating in continental climates. - **Bifacial Glass-Glass Construction (PID-Free)** - The dual-glass design (2+2 mm) eliminates the risk of PID degradation and protects cells against moisture ingress and microcracks — critical for solar farms with a 25–30 year operating life. Bifacial architecture enables 5–30% additional energy yield from the rear surface, depending on ground albedo (light gravel, snow, or bare soil). - **30-Year Linear Power Warranty (87.4%)** - GCL guarantees a minimum of 87.4% of nominal power output after 30 years of operation — in line with best-in-class Tier-1 TOPCon products. For a 10 MWp plant, this translates to a contractually guaranteed residual capacity of at least 8.74 MWp over the investment horizon. - **GCL-SI: BNEF Tier 1, Bankable for Years** - GCL System Integration has maintained a continuous presence on the Bloomberg NEF Tier 1 list (confirmed as the #2 manufacturer by production capacity). Bankable status streamlines non-recourse project financing and reduces the cost of capital for large-scale PV plants — a key consideration for infrastructure funds and project finance lenders. ## Cons - **Discontinued Series** - The GCL-NT12/66GDF series has been discontinued (since 2022/2023). This means limited module availability on the secondary market, a risk of supply shortfalls when replacing failed units over the plant's long operational life, and the absence of dedicated technical support for this series. Current product lines from the manufacturer are recommended for new projects. - **12-Year Product Warranty — Below Premium Standard** - The product warranty stands at 12 years, whereas Tier-1 competitors in this segment — including Trina Vertex N, LONGi Hi-MO X6, and Canadian Solar TOPBiHiKu7 — routinely offer 15 years as standard. The 3-year gap may be material when calculating TCO and meeting project insurers' requirements. ## About this series The GCL-NT12/66GDF series features advanced modules based on **N-type TOPCon technology** that set new performance standards in variable weather conditions. The use of bifacial cells enables efficient energy generation from both sides of the panel, significantly increasing total energy yield, especially in installations on surfaces with high light reflectance. The robust **glass-glass** construction guarantees exceptional resistance to potential-induced degradation (PID) and protects cells from micro-cracks, which translates into long-term financial stability for the investment. Thanks to a low temperature coefficient, these panels operate with high efficiency even on hot days, effectively minimizing power losses. They solve the key problem of limited installation space by offering impressive energy density per square meter. This product is primarily dedicated to professional photovoltaic farms and large commercial systems where the lowest levelized cost of energy (LCOE) is the priority. What sets them apart from competing solutions is **high efficiency in low sunlight** and excellent sealing, which protects the system against corrosion and moisture. Choosing this series means **maximizing gains from bifaciality** while maintaining top-class fire safety and full reliability in harsh operating environments. ## Notable figures - Efficiency of 23.3% matches the \*\*TOPCon 700-750W\*\* median - Power density of 233.4 W/m² packs 3.2 W/m² more into the same footprint vs \*\*TOPCon 700-750W\*\* median (230.2 W/m²) - Temperature coefficient of -0.29%/°C matches the \*\*TOPCon 700-750W\*\* median - Bifacial design (80% factor) captures reflected light - adds 4-12% yield on ground-mount or white roof - Ranked #943 out of 14005 panels for efficiency in the database ## Questions ### Is the GCL-NT12/66GDF series still available for purchase? The GCL-NT12/66GDF series has been discontinued and is no longer actively offered by the manufacturer GCL. Availability through distributors may be limited to remaining inventory stock. If you are planning a new installation or expanding an existing one, it is advisable to contact your supplier directly to confirm availability, or to explore current replacement models from GCL's lineup based on the same N-type TOPCon technology. ### What warranty coverage applies to the GCL-NT12/66GDF panels? GCL provides a 12-year product warranty on the GCL-NT12/66GDF series, covering material and manufacturing defects. In addition, a 30-year linear power output warranty applies, guaranteeing that the modules retain at least 87.4% of their nominal rated power after a full 30 years of operation. This is among the longer warranty standards available on the market today, reflecting the high build quality of these modules. ### How do the GCL-NT12/66GDF panels perform on hot days — is power loss significant? The GCL-NT12/66GDF series features a low temperature coefficient for Pmax of just -0.29%/°C. This means that for every degree Celsius rise in cell temperature, the module loses only 0.29% of its rated power output. In practice, under typical Central European summer conditions, these modules perform noticeably better than older P-type panels, whose temperature coefficient frequently reaches -0.35%/°C or higher. ### Is the GCL-NT12/66GDF a good choice for a large-scale solar farm? Yes, the GCL-NT12/66GDF series was designed primarily for commercial solar farms and large industrial PV installations. A maximum power output of up to 730 Wp, combined with a glass-glass construction and bifacial technology, enables optimization of the LCOE (Levelized Cost of Energy). It should be noted, however, that the module dimensions of 2384×1303×35 mm and a weight of approximately 38.3 kg require a robust racking structure and professional installation equipment. ### How does bifaciality work in the GCL-NT12/66GDF panels, and how much additional energy can be gained? The GCL-NT12/66GDF modules are bifacial — the rear surface of the N-type TOPCon cell captures light reflected from the ground surface (snow, light-colored gravel, roofing membrane). The additional energy yield from the rear side typically ranges from 5% to 25%, depending on the ground albedo and the tilt angle of the installation. The greatest bifacial gains are achieved in ground-mounted systems with a light-colored substrate and a sufficiently large clearance gap beneath the modules. ### How does the N-type TOPCon technology used in the GCL-NT12/66GDF differ from older PERC cells? The N-type TOPCon cells in the GCL-NT12/66GDF series deliver higher efficiency (up to 23.5%) and significantly lower initial light-induced degradation (LID) compared to conventional P-type PERC cells. The N-type silicon substrate is inherently less susceptible to impurities, while the TOPCon tunnel passivation layer reduces charge carrier recombination. The result is more stable long-term performance throughout the system's service life and higher annual energy yield — particularly under the diffuse, overcast irradiance conditions characteristic of Central European climates. ## Datasheet [Manufacturer datasheet (PDF)](https://comparepv.com/datasheets/Aus-NT1266GDF715-725-217f103fd8cf.pdf) ## Alternatives | Panel | Power | How it differs | | --- | --- | --- | | [AIKO AIKO-A680-MDE72Mw](https://comparepv.com/panel/aiko-aiko-a680-mde72mw) | 680 W | -45 W, lighter, +1.9 pp | | [AIKO AIKO-A675-MDE72Mw](https://comparepv.com/panel/aiko-aiko-a675-mde72mw) | 675 W | -50 W, lighter, +1.7 pp | | [AIKO AIKO-A700-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a700-mae78dw) | 700 W | Cooler, lighter, +1.7 pp | | [AIKO AIKO-A695-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a695-mae78dw) | 695 W | -30 W, lighter, +1.6 pp | | [AIKO AIKO-A690-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a690-mae78dw) | 690 W | -35 W, lighter, +1.4 pp | | [AIKO AIKO-A685-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a685-mae78dw) | 685 W | -40 W, lighter, +1.2 pp | | [Trina Solar TSM-NEG21C.20Q-760](https://comparepv.com/panel/trina-solar-tsm-neg21c-20q-760) | 760 W | +35 W, cooler, +1.2 pp | | [AIKO AIKO-A680-MAH78Dw](https://comparepv.com/panel/aiko-aiko-a680-mah78dw) | 680 W | -45 W, lighter, +1.0 pp | | [GCL GCL-M12/66GDF-655W](https://comparepv.com/panel/gcl-gcl-m12-66gdf-655w) | 655 W | -70 W, hotter, -2.2 pp | | [GCL GCL-M12/66H-660W](https://comparepv.com/panel/gcl-gcl-m12-66h-660w) | 660 W | -65 W, hotter, -2.1 pp | | [GCL GCL-M12/66H-665W](https://comparepv.com/panel/gcl-gcl-m12-66h-665w) | 665 W | -60 W, hotter, -1.9 pp | | [AIKO AIKO-A805-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a805-grh78dw) | 805 W | +80 W, cooler, +1.8 pp | | [AIKO AIKO-A800-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a800-grh78dw) | 800 W | +75 W, cooler, +1.6 pp | | [AIKO AIKO-A795-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a795-grh78dw) | 795 W | +70 W, cooler, +1.5 pp | | [AIKO AIKO-A790-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a790-grh78dw) | 790 W | +65 W, cooler, +1.3 pp | | [AIKO AIKO-A785-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a785-grh78dw) | 785 W | +60 W, cooler, +1.1 pp | --- Source: https://comparepv.com/panel/gcl-gcl-nt12-66gdf-725-1 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.