--- title: "Tongwei TWMNF-66HD740 vs Tongwei TWMNF-66HD745 - Solar Panel Comparison | ComparePV" description: "Compare Tongwei TWMNF-66HD740 vs Tongwei TWMNF-66HD745 side by side: what actually differs, output when it is hot, thirty-year production, and the full specification." source: "https://comparepv.com/compare/tongwei-solar-twmnf-66hd740/tongwei-solar-twmnf-66hd745" updated: 2026-09-11 --- # Tongwei TWMNF-66HD740 vs Tongwei TWMNF-66HD745 66HD745 leads on the differences that matter The largest is module efficiency: 0.20 pp more efficient. 18 of 19 comparable parameters are identical. ## The two panels | Attribute | A | B | | --- | --- | --- | | Panel | [Tongwei TWMNF-66HD740](https://comparepv.com/panel/tongwei-solar-twmnf-66hd740) | [Tongwei TWMNF-66HD745](https://comparepv.com/panel/tongwei-solar-twmnf-66hd745) | | Manufacturer | Tongwei | Tongwei | | Power | 740 Wp | 745 Wp | | Efficiency | 23.80 % | 24.00 % | | Technology | TOPCon | TOPCon | ## Where they differ Ranked by how much the difference matters, not by datasheet order. | Parameter | 66HD740 | 66HD745 | Difference | | --- | --- | --- | --- | | Module efficiency | 23.80 % | 24.00 % | +0.20 pp for 66HD745 | ## Every compared parameter | Parameter | 66HD740 | 66HD745 | | --- | --- | --- | | Rated power | 740 Wp | 745 Wp | | Module efficiency | 23.80 % | 24.00 % | | Power density | 238.2 Wp/m² | 239.8 Wp/m² | | Open-circuit voltage | 49.80 V | 49.95 V | | Voltage at max power | 41.69 V | 41.86 V | | Short-circuit current | 18.81 A | 18.87 A | | Current at max power | 17.75 A | 17.80 A | | Temperature coefficient | -0.280 %/°C | -0.280 %/°C | | Dimensions | 2384x1303x33 mm | 2384x1303x33 mm | | Module area | 3.106 m² | 3.106 m² | | Weight | 37.3 kg | 37.3 kg | | Weight per kWp | 50.4 kg/kWp | 50.1 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 (-0.280 %/°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, 66HD740:** 24,828 kWh - **Cumulative output, 66HD745:** 24,996 kWh - **Gap:** 168 kWh ## Output when hot | Condition | Cell temperature | 66HD740 | 66HD745 | Retained | | --- | --- | --- | --- | --- | | Standard test conditions | 25 °C | 740 W | 745 W | 100.0% of rated power | | Cool, bright day | 40 °C | 709 W | 714 W | 95.8% of rated power | | Typical summer roof | 55 °C | 678 W | 682 W | 91.6% of rated power | | Hot roof | 70 °C | 647 W | 651 W | 87.4% of rated power | ## Against the whole database | Measure | 66HD740 | 66HD745 | Out of | Note | | --- | --- | --- | --- | --- | | Efficiency | #433 | #303 | 14,005 | 66HD745 leads by 130 places | | Power density | #431 | #339 | 14,005 | 66HD745 leads by 92 places | | Heat behaviour | #1,309 | #1,309 | 14,005 | Tied - the same position in the database | | Weight | #3,784 | #3,586 | 14,005 | 66HD745 leads by 198 places | | Warranty | #21 | #21 | 14,005 | Tied - the same position in the database | | Overall | #183 | #148 | 14,005 | 66HD745 leads by 35 places | ## Questions ### Which panel is better: Tongwei TWMNF-66HD740 or Tongwei TWMNF-66HD745? According to our database: **Tongwei TWMNF-66HD745** has higher module efficiency (**24.00%** vs **23.80%**). See the full spec comparison and 30-year energy simulation above for a complete picture. ### What is the efficiency of Tongwei TWMNF-66HD740 and Tongwei TWMNF-66HD745? **Tongwei TWMNF-66HD740** has a module efficiency of **23.80%**, while **Tongwei TWMNF-66HD745** is **24.00%**. Higher efficiency means more electricity from the same roof area - useful when space is limited. ### What cell technology does Tongwei TWMNF-66HD740 use vs Tongwei TWMNF-66HD745? **Tongwei TWMNF-66HD740** uses **TOPCon** cells; **Tongwei TWMNF-66HD745** 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 Tongwei TWMNF-66HD740 and Tongwei TWMNF-66HD745? **Tongwei TWMNF-66HD740** has a **30 years** power warranty; **Tongwei TWMNF-66HD745** 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 Tongwei TWMNF-66HD740 and Tongwei TWMNF-66HD745 bifacial panels? Both **Tongwei TWMNF-66HD740** and **Tongwei TWMNF-66HD745** 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 - [Tongwei TWMNF-66HD740 vs Tongwei TWMNF-66HD750](https://comparepv.com/compare/tongwei-solar-twmnf-66hd740/tongwei-solar-twmnf-66hd750) - 3 differences, the largest is module efficiency - [Tongwei TWMNF-66HD740 vs Tongwei TWMNF-66HD735](https://comparepv.com/compare/tongwei-solar-twmnf-66hd740/tongwei-solar-twmnf-66hd735) - The same specification on paper - [Tongwei TWMNF-66HD740 vs Tongwei TWMNF-66HD730](https://comparepv.com/compare/tongwei-solar-twmnf-66hd740/tongwei-solar-twmnf-66hd730) - 3 differences, the largest is module efficiency - [Tongwei TWMNF-66HD740 vs Tongwei TWMHF-66HD740X](https://comparepv.com/compare/tongwei-solar-twmnf-66hd740/tw-solar-twmhf-66hd740x) - 3 differences, the largest is temperature coefficient - [Tongwei TWMNF-66HD740 vs Tongwei THC G12-66 Bifacial](https://comparepv.com/compare/tongwei-solar-twmnf-66hd740/tongwei-thc-g12-66-bifacial) - One difference: product warranty - [Tongwei TWMNF-66HD740 vs Tongwei TWMHF-66HD735X](https://comparepv.com/compare/tongwei-solar-twmnf-66hd740/tw-solar-twmhf-66hd735x) - 3 differences, the largest is temperature coefficient --- Source: https://comparepv.com/compare/tongwei-solar-twmnf-66hd740/tongwei-solar-twmnf-66hd745 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.