--- title: "GCL GCL-NT12/66GDF 725 vs GCL GCL-NT12/66GDF-735 - Solar Panel Comparison | ComparePV" description: "Compare GCL GCL-NT12/66GDF 725 vs GCL GCL-NT12/66GDF-735 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-725-1/gcl-gcl-nt12-66gdf-735" updated: 2026-09-11 --- # GCL GCL-NT12/66GDF 725 vs GCL GCL-NT12/66GDF-735 66GDF-735 leads on the differences that matter The largest is module efficiency: 0.32 pp more efficient. 15 of 18 comparable parameters are identical, with 1 more left out because at least one datasheet does not publish it. ## The two panels | Attribute | A | B | | --- | --- | --- | | Panel | [GCL GCL-NT12/66GDF 725](https://comparepv.com/panel/gcl-gcl-nt12-66gdf-725-1) | [GCL GCL-NT12/66GDF-735](https://comparepv.com/panel/gcl-gcl-nt12-66gdf-735) | | Manufacturer | GCL | GCL | | Power | 725 Wp | 735 Wp | | Efficiency | 23.34 % | 23.66 % | | Technology | TOPCon | TOPCon | ## Where they differ Ranked by how much the difference matters, not by datasheet order. | Parameter | 66GDF 725 | 66GDF-735 | Difference | | --- | --- | --- | --- | | Module efficiency | 23.34 % | 23.66 % | +0.32 pp for 66GDF-735 | | Power density | 233.4 Wp/m² | 236.6 Wp/m² | +3.2 Wp/m² for 66GDF-735 | | Rated power | 725 Wp | 735 Wp | +10 W for 66GDF-735 | ## Every compared parameter | Parameter | 66GDF 725 | 66GDF-735 | | --- | --- | --- | | Rated power | 725 Wp | 735 Wp | | Module efficiency | 23.34 % | 23.66 % | | Power density | 233.4 Wp/m² | 236.6 Wp/m² | | Open-circuit voltage | 48.80 V | 49.24 V | | Voltage at max power | 41.03 V | 41.41 V | | Short-circuit current | 18.60 A | 18.68 A | | Current at max power | 17.67 A | 17.75 A | | Temperature coefficient | -0.290 %/°C | -0.290 %/°C | | Dimensions | 2384x1303x33 mm | 2384x1303x33 mm | | Module area | 3.106 m² | 3.106 m² | | Weight | 38.3 kg | 38.2 kg | | Weight per kWp | 52.8 kg/kWp | 52.0 kg/kWp | | Product warranty | 12 yrs | 12 yrs | | Performance warranty | 30 yrs | 30 yrs | | Annual degradation | - | 0.40 %/yr | | Cell technology | TOPCon | TOPCon | | Cell type | Monocrystalline | Monocrystalline | | Cell count | 132 | 132 | | Bifacial | Yes | Yes | ## Thirty-year yield A 1.0% first-year loss then 0.40% a year, assumed for both panels, 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, 66GDF 725:** 24,325 kWh - **Cumulative output, 66GDF-735:** 24,661 kWh - **Gap:** 336 kWh ## Output when hot | Condition | Cell temperature | 66GDF 725 | 66GDF-735 | Retained | | --- | --- | --- | --- | --- | | Standard test conditions | 25 °C | 725 W | 735 W | 100.0% of rated power | | Cool, bright day | 40 °C | 693 W | 703 W | 95.7% of rated power | | Typical summer roof | 55 °C | 662 W | 671 W | 91.3% of rated power | | Hot roof | 70 °C | 630 W | 639 W | 87.0% of rated power | ## Against the whole database | Measure | 66GDF 725 | 66GDF-735 | Out of | Note | | --- | --- | --- | --- | --- | | Efficiency | #943 | #602 | 14,005 | 66GDF-735 leads by 341 places | | Power density | #936 | #582 | 14,005 | 66GDF-735 leads by 354 places | | Heat behaviour | #2,165 | #2,165 | 14,005 | Tied - the same position in the database | | Weight | #6,514 | #5,413 | 14,005 | 66GDF-735 leads by 1,101 places | | Warranty | #21 | #21 | 14,005 | Tied - the same position in the database | | Overall | #403 | #244 | 14,005 | 66GDF-735 leads by 159 places | ## Questions ### Which panel is better: GCL GCL-NT12/66GDF 725 or GCL GCL-NT12/66GDF-735? According to our database: **GCL GCL-NT12/66GDF-735** has higher module efficiency (**23.66%** vs **23.34%**). See the full spec comparison and 30-year energy simulation above for a complete picture. ### What is the efficiency of GCL GCL-NT12/66GDF 725 and GCL GCL-NT12/66GDF-735? **GCL GCL-NT12/66GDF 725** has a module efficiency of **23.34%**, while **GCL GCL-NT12/66GDF-735** is **23.66%**. Higher efficiency means more electricity from the same roof area - useful when space is limited. ### What cell technology does GCL GCL-NT12/66GDF 725 use vs GCL GCL-NT12/66GDF-735? **GCL GCL-NT12/66GDF 725** uses **TOPCon** cells; **GCL GCL-NT12/66GDF-735** 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 725 and GCL GCL-NT12/66GDF-735? **GCL GCL-NT12/66GDF 725** has a **30 years** power warranty; **GCL GCL-NT12/66GDF-735** 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 725 and GCL GCL-NT12/66GDF-735 bifacial panels? Both **GCL GCL-NT12/66GDF 725** and **GCL GCL-NT12/66GDF-735** 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 725 vs GCL GCL-NT12/66GDF-740](https://comparepv.com/compare/gcl-gcl-nt12-66gdf-725-1/gcl-gcl-nt12-66gdf-740) - 3 differences, the largest is module efficiency - [GCL GCL-NT12/66GDF 725 vs GCL GCL-NT12/66GDF-730](https://comparepv.com/compare/gcl-gcl-nt12-66gdf-725-1/gcl-gcl-nt12-66gdf-730) - The same specification on paper - [GCL GCL-NT12/66GDF 725 vs GCL NT12/66GDF-730](https://comparepv.com/compare/gcl-gcl-nt12-66gdf-725-1/gcl-nt12-66gdf-730) - The same specification on paper - [GCL GCL-NT12/66GDF 725 vs GCL GCL-NT12/66GDF-725](https://comparepv.com/compare/gcl-gcl-nt12-66gdf-725-1/gcl-gcl-nt12-66gdf-725) - The same specification on paper - [GCL GCL-NT12/66GDF 725 vs GCL NT12/66GDF-725](https://comparepv.com/compare/gcl-gcl-nt12-66gdf-725-1/gcl-nt12-66gdf-725) - The same specification on paper - [GCL GCL-NT12/66GDF 725 vs GCL GCL-NT12/66GDF-720](https://comparepv.com/compare/gcl-gcl-nt12-66gdf-725-1/gcl-gcl-nt12-66gdf-720) - The same specification on paper --- Source: https://comparepv.com/compare/gcl-gcl-nt12-66gdf-725-1/gcl-gcl-nt12-66gdf-735 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.