--- title: "Suntech STP665S-D66/Wmh vs Suntech STP700S-D66-Nsh+ - Solar Panel Comparison | ComparePV" description: "Compare Suntech STP665S-D66/Wmh vs Suntech STP700S-D66-Nsh+ side by side: what actually differs, output when it is hot, thirty-year production, and the full specification." source: "https://comparepv.com/compare/suntech-stp665s-d66-wmh/suntech-stp700s-d66-nsh" updated: 2026-09-11 --- # Suntech STP665S-D66/Wmh vs Suntech STP700S-D66-Nsh+ STP700S-D66-Nsh+ leads on the differences that matter The largest is module efficiency: 1.10 pp more efficient. 7 of 19 comparable parameters are identical. ## The two panels | Attribute | A | B | | --- | --- | --- | | Panel | [Suntech STP665S-D66/Wmh](https://comparepv.com/panel/suntech-stp665s-d66-wmh) | [Suntech STP700S-D66-Nsh+](https://comparepv.com/panel/suntech-stp700s-d66-nsh) | | Manufacturer | Suntech | Suntech | | Power | 665 Wp | 700 Wp | | Efficiency | 21.40 % | 22.50 % | | Technology | TOPCon | TOPCon | ## Where they differ Ranked by how much the difference matters, not by datasheet order. | Parameter | STP665S-D66/Wmh | STP700S-D66-Nsh+ | Difference | | --- | --- | --- | --- | | Module efficiency | 21.40 % | 22.50 % | +1.10 pp for STP700S-D66-Nsh+ | | Temperature coefficient | -0.340 %/°C | -0.290 %/°C | +0.050 %/°C for STP700S-D66-Nsh+ | | Performance warranty | 25 yrs | 30 yrs | +5 yrs for STP700S-D66-Nsh+ | | Power density | 214.1 Wp/m² | 225.3 Wp/m² | +11.3 Wp/m² for STP700S-D66-Nsh+ | | Rated power | 665 Wp | 700 Wp | +35 W for STP700S-D66-Nsh+ | | Annual degradation | 0.55 %/yr | 0.40 %/yr | -0.15 %/yr for STP700S-D66-Nsh+ | | Weight | 33.5 kg | 37.5 kg | -4.0 kg for STP665S-D66/Wmh | | Product warranty | 12 yrs | 15 yrs | +3 yrs for STP700S-D66-Nsh+ | | Weight per kWp | 50.4 kg/kWp | 53.6 kg/kWp | -3.2 kg/kWp for STP665S-D66/Wmh | | Bifacial | No | Yes | No vs Yes | | Open-circuit voltage | 46.25 V | 47.65 V | 1.40 V apart | | Voltage at max power | 38.25 V | 39.65 V | 1.40 V apart | ## Every compared parameter | Parameter | STP665S-D66/Wmh | STP700S-D66-Nsh+ | | --- | --- | --- | | Rated power | 665 Wp | 700 Wp | | Module efficiency | 21.40 % | 22.50 % | | Power density | 214.1 Wp/m² | 225.3 Wp/m² | | Open-circuit voltage | 46.25 V | 47.65 V | | Voltage at max power | 38.25 V | 39.65 V | | Short-circuit current | 18.39 A | 18.67 A | | Current at max power | 17.39 A | 17.66 A | | Temperature coefficient | -0.340 %/°C | -0.290 %/°C | | Dimensions | 2384x1303x35 mm | 2384x1303x35 mm | | Module area | 3.106 m² | 3.106 m² | | Weight | 33.5 kg | 37.5 kg | | Weight per kWp | 50.4 kg/kWp | 53.6 kg/kWp | | Product warranty | 12 yrs | 15 yrs | | Performance warranty | 25 yrs | 30 yrs | | Annual degradation | 0.55 %/yr | 0.40 %/yr | | Cell technology | TOPCon | TOPCon | | Cell type | Monocrystalline | Monocrystalline | | Cell count | 132 | 132 | | Bifacial | No | Yes | ## Thirty-year yield Each panel's own declared degradation curve, at 1,200 kWh/kWp a year - **Cumulative output, STP665S-D66/Wmh:** 21,552 kWh - **Cumulative output, STP700S-D66-Nsh+:** 23,486 kWh - **Gap:** 1,934 kWh ## Output when hot | Condition | Cell temperature | STP665S-D66/Wmh | STP700S-D66-Nsh+ | Retained | | --- | --- | --- | --- | --- | | Standard test conditions | 25 °C | 665 W | 700 W | 100.0% of rated power | | Cool, bright day | 40 °C | 631 W | 670 W | 94.9% of rated power | | Typical summer roof | 55 °C | 597 W | 639 W | 89.8% of rated power | | Hot roof | 70 °C | 563 W | 609 W | 84.7% of rated power | ## Against the whole database | Measure | STP665S-D66/Wmh | STP700S-D66-Nsh+ | Out of | Note | | --- | --- | --- | --- | --- | | Efficiency | #8,323 | #4,222 | 14,005 | STP700S-D66-Nsh+ leads by 4,101 places | | Power density | #8,250 | #3,989 | 14,005 | STP700S-D66-Nsh+ leads by 4,261 places | | Heat behaviour | #8,778 | #2,165 | 14,005 | STP700S-D66-Nsh+ leads by 6,613 places | | Weight | #3,742 | #7,586 | 14,005 | STP665S-D66/Wmh leads by 3,844 places | | Warranty | #9,798 | #21 | 14,005 | STP700S-D66-Nsh+ leads by 9,777 places | | Overall | #3,792 | #936 | 14,005 | STP700S-D66-Nsh+ leads by 2,856 places | ## Questions ### Which panel is better: Suntech STP665S-D66/Wmh or Suntech STP700S-D66-Nsh+? According to our database: **Suntech STP700S-D66-Nsh+** has higher module efficiency (**22.50%** vs **21.40%**); **Suntech STP700S-D66-Nsh+** tolerates heat better (temp coeff **-0.290%/°C** vs **-0.340%/°C**). See the full spec comparison and 30-year energy simulation above for a complete picture. ### What is the efficiency of Suntech STP665S-D66/Wmh and Suntech STP700S-D66-Nsh+? **Suntech STP665S-D66/Wmh** has a module efficiency of **21.40%**, while **Suntech STP700S-D66-Nsh+** is **22.50%**. Higher efficiency means more electricity from the same roof area - useful when space is limited. ### What cell technology does Suntech STP665S-D66/Wmh use vs Suntech STP700S-D66-Nsh+? **Suntech STP665S-D66/Wmh** uses **TOPCon** cells; **Suntech STP700S-D66-Nsh+** 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 Suntech STP665S-D66/Wmh and Suntech STP700S-D66-Nsh+? **Suntech STP665S-D66/Wmh** has a **25 years** power warranty; **Suntech STP700S-D66-Nsh+** 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 Suntech STP665S-D66/Wmh and Suntech STP700S-D66-Nsh+ bifacial panels? **Suntech STP700S-D66-Nsh+** is bifacial (captures light from both faces); **Suntech STP665S-D66/Wmh** is monofacial. Bifacial panels work best on ground mounts or raised structures with a light-coloured surface underneath. ## Related comparisons - [Suntech STP665S-D66/Wmh vs Suntech STP675S-D66/Wmh](https://comparepv.com/compare/suntech-stp665s-d66-wmh/suntech-stp675s-d66-wmh) - 3 differences, the largest is module efficiency - [Suntech STP665S-D66/Wmh vs Suntech STP670S-D66/Wmh](https://comparepv.com/compare/suntech-stp665s-d66-wmh/suntech-stp670s-d66-wmh) - One difference: module efficiency - [Suntech STP665S-D66/Wmh vs Suntech STP670S-D66/Pmh+](https://comparepv.com/compare/suntech-stp665s-d66-wmh/wuxi-suntech-power-co-ltd-stp670s-d66-pmh) - 7 differences, the largest is performance warranty - [Suntech STP665S-D66/Wmh vs Suntech STP665S-D66/Pmh+](https://comparepv.com/compare/suntech-stp665s-d66-wmh/wuxi-suntech-power-co-ltd-stp665s-d66-pmh) - 6 differences, the largest is performance warranty - [Suntech STP665S-D66/Wmh vs Suntech STP660S-D66/Wmh](https://comparepv.com/compare/suntech-stp665s-d66-wmh/suntech-stp660s-d66-wmh) - One difference: module efficiency - [Suntech STP665S-D66/Wmh vs Suntech STP660S-D66/Pmh+](https://comparepv.com/compare/suntech-stp665s-d66-wmh/wuxi-suntech-power-co-ltd-stp660s-d66-pmh) - 7 differences, the largest is performance warranty --- Source: https://comparepv.com/compare/suntech-stp665s-d66-wmh/suntech-stp700s-d66-nsh 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.