--- title: "GCL GCL-NT12/66GDF-740 vs GCL GCL-NT12R/66GDF-625 - Solar Panel Comparison | ComparePV" description: "Compare GCL GCL-NT12/66GDF-740 vs GCL GCL-NT12R/66GDF-625 side by side: what actually differs, output when it is hot, thirty-year production, and the full specification." source: "https://comparepv.com/compare/gcl-gcl-nt12-66gdf-740/gcl-gcl-nt12r-66gdf-625" image: "https://comparepv.com/og/compare/panels/gcl-gcl-nt12-66gdf-740/gcl-gcl-nt12r-66gdf-625.png" updated: 2026-09-11 --- # GCL GCL-NT12/66GDF-740 vs GCL GCL-NT12R/66GDF-625 NT12/66GDF-740 leads on the differences that matter The largest is module efficiency: 0.68 pp more efficient. 11 of 19 comparable parameters are identical. ## The two panels | Attribute | A | B | | --- | --- | --- | | Panel | [GCL GCL-NT12/66GDF-740](https://comparepv.com/panel/gcl-gcl-nt12-66gdf-740) | [GCL GCL-NT12R/66GDF-625](https://comparepv.com/panel/gcl-gcl-nt12r-66gdf-625) | | Manufacturer | GCL | GCL | | Power | 740 Wp | 625 Wp | | Efficiency | 23.82 % | 23.14 % | | Technology | TOPCon | TOPCon | ## Where they differ Ranked by how much the difference matters, not by datasheet order. | Parameter | NT12/66GDF-740 | NT12R/66GDF-625 | Difference | | --- | --- | --- | --- | | Module efficiency | 23.82 % | 23.14 % | +0.68 pp for NT12/66GDF-740 | | Rated power | 740 Wp | 625 Wp | +115 W for NT12/66GDF-740 | | Weight | 38.2 kg | 32.5 kg | -5.7 kg for NT12R/66GDF-625 | | Power density | 238.2 Wp/m² | 231.4 Wp/m² | +6.8 Wp/m² for NT12/66GDF-740 | | Short-circuit current | 18.72 A | 16.00 A | 2.72 A apart | | Module area | 3.106 m² | 2.701 m² | 0.405 m² apart | | Current at max power | 17.79 A | 15.20 A | 2.59 A apart | | Dimensions | 2384x1303x33 mm | 2382x1134x30 mm | 2384x1303x33 mm vs 2382x1134x30 mm | ## Every compared parameter | Parameter | NT12/66GDF-740 | NT12R/66GDF-625 | | --- | --- | --- | | Rated power | 740 Wp | 625 Wp | | Module efficiency | 23.82 % | 23.14 % | | Power density | 238.2 Wp/m² | 231.4 Wp/m² | | Open-circuit voltage | 49.46 V | 48.55 V | | Voltage at max power | 41.60 V | 41.12 V | | Short-circuit current | 18.72 A | 16.00 A | | Current at max power | 17.79 A | 15.20 A | | Temperature coefficient | -0.290 %/°C | -0.290 %/°C | | Dimensions | 2384x1303x33 mm | 2382x1134x30 mm | | Module area | 3.106 m² | 2.701 m² | | Weight | 38.2 kg | 32.5 kg | | Weight per kWp | 51.6 kg/kWp | 52.0 kg/kWp | | Product warranty | 12 yrs | 12 yrs | | Performance warranty | 30 yrs | 30 yrs | | Annual degradation | 0.40 %/yr | 0.40 %/yr | | Cell technology | TOPCon | TOPCon | | Cell type | Monocrystalline | Monocrystalline | | Cell count | 132 | 132 | | Bifacial | Yes | Yes | ## Thirty-year yield Each panel's own declared degradation curve, at 1,200 kWh/kWp a year Same temp coeff. for both panels (-0.290 %/°C), so a warmer roof scales both curves by the same factor: the totals fall together and neither panel gains on the other. - **Cumulative output, NT12/66GDF-740:** 24,828 kWh - **Cumulative output, NT12R/66GDF-625:** 20,970 kWh - **Gap:** 3,858 kWh ## Output when hot | Condition | Cell temperature | NT12/66GDF-740 | NT12R/66GDF-625 | Retained | | --- | --- | --- | --- | --- | | Standard test conditions | 25 °C | 740 W | 625 W | 100.0% of rated power | | Cool, bright day | 40 °C | 708 W | 598 W | 95.7% of rated power | | Typical summer roof | 55 °C | 676 W | 571 W | 91.3% of rated power | | Hot roof | 70 °C | 643 W | 543 W | 87.0% of rated power | ## Against the whole database | Measure | NT12/66GDF-740 | NT12R/66GDF-625 | Out of | Note | | --- | --- | --- | --- | --- | | Efficiency | #447 | #1,554 | 14,129 | NT12/66GDF-740 leads by 1,107 places | | Power density | #460 | #1,558 | 14,129 | NT12/66GDF-740 leads by 1,098 places | | Heat behaviour | #2,220 | #2,220 | 14,129 | Tied - the same position in the database | | Weight | #5,026 | #5,449 | 14,129 | NT12/66GDF-740 leads by 423 places | | Warranty | #21 | #21 | 14,129 | Tied - the same position in the database | | Overall | #181 | #2,266 | 14,129 | NT12/66GDF-740 leads by 2,085 places | ## Questions ### Which panel is better: GCL GCL-NT12/66GDF-740 or GCL GCL-NT12R/66GDF-625? According to our database: **GCL GCL-NT12/66GDF-740** has higher module efficiency (**23.82%** vs **23.14%**). See the full spec comparison and 30-year energy simulation above for a complete picture. ### What is the efficiency of GCL GCL-NT12/66GDF-740 and GCL GCL-NT12R/66GDF-625? **GCL GCL-NT12/66GDF-740** has a module efficiency of **23.82%**, while **GCL GCL-NT12R/66GDF-625** is **23.14%**. Higher efficiency means more electricity from the same roof area - useful when space is limited. ### What cell technology does GCL GCL-NT12/66GDF-740 use vs GCL GCL-NT12R/66GDF-625? **GCL GCL-NT12/66GDF-740** uses **TOPCon** cells; **GCL GCL-NT12R/66GDF-625** uses **TOPCon**. Modern **n-type** technologies (**TOPCon**, **HJT**, BC) typically deliver higher efficiency and lower degradation compared to older **PERC** (p-type) cells. ### What is the warranty on GCL GCL-NT12/66GDF-740 and GCL GCL-NT12R/66GDF-625? **GCL GCL-NT12/66GDF-740** has a **30 years** power warranty; **GCL GCL-NT12R/66GDF-625** has a **30 years** power warranty. The power warranty guarantees a minimum percentage of rated output at the end of the warranty period (typically 80**-87%**). Product (materials) warranties are usually shorter. ### Are GCL GCL-NT12/66GDF-740 and GCL GCL-NT12R/66GDF-625 bifacial panels? Both **GCL GCL-NT12/66GDF-740** and **GCL GCL-NT12R/66GDF-625** are bifacial - they capture reflected light from the ground, which can add 5**-15%** more annual energy on ground-mount or elevated rooftop installations with a light surface beneath. ## Related comparisons - [GCL GCL-NT12/66GDF-740 vs GCL GCL-NT12/66GDF-735](https://comparepv.com/compare/gcl-gcl-nt12-66gdf-740/gcl-gcl-nt12-66gdf-735) - The same specification on paper - [GCL GCL-NT12/66GDF-740 vs GCL GCL-NT12/66GDF-730](https://comparepv.com/compare/gcl-gcl-nt12-66gdf-740/gcl-gcl-nt12-66gdf-730) - 3 differences, the largest is module efficiency - [GCL GCL-NT12/66GDF-740 vs GCL NT12/66GDF-730](https://comparepv.com/compare/gcl-gcl-nt12-66gdf-740/gcl-nt12-66gdf-730) - 3 differences, the largest is module efficiency - [GCL GCL-NT12/66GDF-740 vs GCL GCL-NT12/66GDF-725](https://comparepv.com/compare/gcl-gcl-nt12-66gdf-740/gcl-gcl-nt12-66gdf-725) - 3 differences, the largest is module efficiency - [GCL GCL-NT12/66GDF-740 vs GCL NT12/66GDF-725](https://comparepv.com/compare/gcl-gcl-nt12-66gdf-740/gcl-nt12-66gdf-725) - 3 differences, the largest is module efficiency - [GCL GCL-NT12/66GDF-740 vs GCL GCL-NT12/66GDF 725](https://comparepv.com/compare/gcl-gcl-nt12-66gdf-740/gcl-gcl-nt12-66gdf-725-1) - 3 differences, the largest is module efficiency --- Source: https://comparepv.com/compare/gcl-gcl-nt12-66gdf-740/gcl-gcl-nt12r-66gdf-625 Not in this file, on the page: the thirty-year yield curve year by year at a cell temperature you pick and a written summary generated on request.