--- title: "Gokin GK-4-78HGBD-780M vs Sharp GSD8K66H-740WT - Solar Panel Comparison | ComparePV" description: "Compare Gokin GK-4-78HGBD-780M vs Sharp GSD8K66H-740WT side by side: what actually differs, output when it is hot, thirty-year production, and the full specification." source: "https://comparepv.com/compare/gokin-gk-4-78hgbd-780m/sharp-gsd8k66h-740wt" updated: 2026-09-11 --- # Gokin GK-4-78HGBD-780M vs Sharp GSD8K66H-740WT GK-4-78HGBD-780M leads on the differences that matter The largest is rated power: 40 W more power. 6 of 19 comparable parameters are identical. ## The two panels | Attribute | A | B | | --- | --- | --- | | Panel | [Gokin GK-4-78HGBD-780M](https://comparepv.com/panel/gokin-gk-4-78hgbd-780m) | [Sharp GSD8K66H-740WT](https://comparepv.com/panel/sharp-gsd8k66h-740wt) | | Manufacturer | Gokin | Sharp | | Power | 780 Wp | 740 Wp | | Efficiency | 24.30 % | 23.82 % | | Technology | Back Contact | HJT | ## Where they differ Ranked by how much the difference matters, not by datasheet order. | Parameter | GK-4-78HGBD-780M | GSD8K66H-740WT | Difference | | --- | --- | --- | --- | | Rated power | 780 Wp | 740 Wp | +40 W for GK-4-78HGBD-780M | | Module efficiency | 24.30 % | 23.82 % | +0.48 pp for GK-4-78HGBD-780M | | Product warranty | 15 yrs | 25 yrs | +10 yrs for GSD8K66H-740WT | | Open-circuit voltage | 58.92 V | 51.70 V | 7.22 V apart | | Module area | 3.212 m² | 3.106 m² | 0.106 m² apart | | Power density | 242.8 Wp/m² | 238.2 Wp/m² | +4.6 Wp/m² for GK-4-78HGBD-780M | | Cell technology | Back Contact | HJT | Back Contact vs HJT | | Weight per kWp | 49.6 kg/kWp | 52.7 kg/kWp | -3.1 kg/kWp for GK-4-78HGBD-780M | | Voltage at max power | 48.97 V | 43.80 V | 5.17 V apart | | Cell count | 156 | 132 | 24 cells apart | | Short-circuit current | 16.78 A | 17.76 A | 0.98 A apart | | Dimensions | 2465x1303x33 mm | 2384x1303x35 mm | 2465x1303x33 mm vs 2384x1303x35 mm | | Current at max power | 15.93 A | 16.91 A | 0.98 A apart | ## Every compared parameter | Parameter | GK-4-78HGBD-780M | GSD8K66H-740WT | | --- | --- | --- | | Rated power | 780 Wp | 740 Wp | | Module efficiency | 24.30 % | 23.82 % | | Power density | 242.8 Wp/m² | 238.2 Wp/m² | | Open-circuit voltage | 58.92 V | 51.70 V | | Voltage at max power | 48.97 V | 43.80 V | | Short-circuit current | 16.78 A | 17.76 A | | Current at max power | 15.93 A | 16.91 A | | Temperature coefficient | -0.260 %/°C | -0.260 %/°C | | Dimensions | 2465x1303x33 mm | 2384x1303x35 mm | | Module area | 3.212 m² | 3.106 m² | | Weight | 38.7 kg | 39.0 kg | | Weight per kWp | 49.6 kg/kWp | 52.7 kg/kWp | | Product warranty | 15 yrs | 25 yrs | | Performance warranty | 30 yrs | 30 yrs | | Annual degradation | 0.35 %/yr | 0.35 %/yr | | Cell technology | Back Contact | HJT | | Cell type | Monocrystalline | Monocrystalline | | Cell count | 156 | 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 (-0.260 %/°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, GK-4-78HGBD-780M:** 26,374 kWh - **Cumulative output, GSD8K66H-740WT:** 25,022 kWh - **Gap:** 1,352 kWh ## Output when hot | Condition | Cell temperature | GK-4-78HGBD-780M | GSD8K66H-740WT | Retained | | --- | --- | --- | --- | --- | | Standard test conditions | 25 °C | 780 W | 740 W | 100.0% of rated power | | Cool, bright day | 40 °C | 750 W | 711 W | 96.1% of rated power | | Typical summer roof | 55 °C | 719 W | 682 W | 92.2% of rated power | | Hot roof | 70 °C | 689 W | 653 W | 88.3% of rated power | ## Against the whole database | Measure | GK-4-78HGBD-780M | GSD8K66H-740WT | Out of | Note | | --- | --- | --- | --- | --- | | Efficiency | #131 | #418 | 14,005 | GK-4-78HGBD-780M leads by 287 places | | Power density | #138 | #431 | 14,005 | GK-4-78HGBD-780M leads by 293 places | | Heat behaviour | #511 | #511 | 14,005 | Tied - the same position in the database | | Weight | #3,161 | #6,344 | 14,005 | GK-4-78HGBD-780M leads by 3,183 places | | Warranty | #21 | #21 | 14,005 | Tied - the same position in the database | | Overall | #15 | #12 | 14,005 | GSD8K66H-740WT leads by 3 places | ## Questions ### Which panel is better: Gokin GK-4-78HGBD-780M or Sharp GSD8K66H-740WT? According to our database: **Gokin GK-4-78HGBD-780M** has higher module efficiency (**24.30%** vs **23.82%**). See the full spec comparison and 30-year energy simulation above for a complete picture. ### What is the efficiency of Gokin GK-4-78HGBD-780M and Sharp GSD8K66H-740WT? **Gokin GK-4-78HGBD-780M** has a module efficiency of **24.30%**, while **Sharp GSD8K66H-740WT** is **23.82%**. Higher efficiency means more electricity from the same roof area - useful when space is limited. ### What cell technology does Gokin GK-4-78HGBD-780M use vs Sharp GSD8K66H-740WT? **Gokin GK-4-78HGBD-780M** uses **Back Contact** cells; **Sharp GSD8K66H-740WT** uses **HJT**. 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 Gokin GK-4-78HGBD-780M and Sharp GSD8K66H-740WT? **Gokin GK-4-78HGBD-780M** has a **30 years** power warranty; **Sharp GSD8K66H-740WT** 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 Gokin GK-4-78HGBD-780M and Sharp GSD8K66H-740WT bifacial panels? Both **Gokin GK-4-78HGBD-780M** and **Sharp GSD8K66H-740WT** 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 - [Gokin GK-4-78HGBD-780M vs Gokin GK-4-78HGBD-775M](https://comparepv.com/compare/gokin-gk-4-78hgbd-780m/gokin-gk-4-78hgbd-775m) - One difference: module efficiency - [Gokin GK-4-78HGBD-780M vs Gokin GK-4-78HGBD-770M](https://comparepv.com/compare/gokin-gk-4-78hgbd-780m/gokin-gk-4-78hgbd-770m) - 3 differences, the largest is module efficiency - [Gokin GK-4-78HGBD-780M vs Gokin GK-4-78HGBD-765M](https://comparepv.com/compare/gokin-gk-4-78hgbd-780m/gokin-gk-4-78hgbd-765m) - 3 differences, the largest is module efficiency - [Gokin GK-4-78HGBD-780M vs Gokin GK-4-78HGBD-760M](https://comparepv.com/compare/gokin-gk-4-78hgbd-780m/gokin-gk-4-78hgbd-760m) - 3 differences, the largest is module efficiency - [Sharp GSD8K66H-740WT vs Sharp GSD8K66H-735WT](https://comparepv.com/compare/sharp-gsd8k66h-740wt/sharp-gsd8k66h-735wt) - The same specification on paper - [Sharp GSD8K66H-740WT vs Sharp GSD8K66H-730WT](https://comparepv.com/compare/sharp-gsd8k66h-740wt/sharp-gsd8k66h-730wt) - 3 differences, the largest is module efficiency --- Source: https://comparepv.com/compare/gokin-gk-4-78hgbd-780m/sharp-gsd8k66h-740wt 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.