--- title: "Tongwei TWMNH-66HD645 vs Tongwei TWMHF-66HD740X - Solar Panel Comparison | ComparePV" description: "Compare Tongwei TWMNH-66HD645 vs Tongwei TWMHF-66HD740X 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-twmnh-66hd645/tw-solar-twmhf-66hd740x" updated: 2026-09-11 --- # Tongwei TWMNH-66HD645 vs Tongwei TWMHF-66HD740X TWMHF-66HD740X leads on the differences that matter The largest is temperature coefficient: 0.040 %/°C better in heat. 11 of 19 comparable parameters are identical. ## The two panels | Attribute | A | B | | --- | --- | --- | | Panel | [Tongwei TWMNH-66HD645](https://comparepv.com/panel/tongwei-solar-twmnh-66hd645) | [Tongwei TWMHF-66HD740X](https://comparepv.com/panel/tw-solar-twmhf-66hd740x) | | Manufacturer | Tongwei | Tongwei | | Power | 645 Wp | 740 Wp | | Efficiency | 23.90 % | 23.80 % | | Technology | N-type | N-type | ## Where they differ Ranked by how much the difference matters, not by datasheet order. | Parameter | TWMNH-66HD645 | TWMHF-66HD740X | Difference | | --- | --- | --- | --- | | Temperature coefficient | -0.280 %/°C | -0.240 %/°C | +0.040 %/°C for TWMHF-66HD740X | | Rated power | 645 Wp | 740 Wp | +95 W for TWMHF-66HD740X | | Weight | 32.2 kg | 37.0 kg | -4.8 kg for TWMNH-66HD645 | | Product warranty | 12 yrs | 15 yrs | +3 yrs for TWMHF-66HD740X | | Short-circuit current | 16.39 A | 18.47 A | 2.08 A apart | | Module area | 2.701 m² | 3.106 m² | 0.405 m² apart | | Current at max power | 15.54 A | 17.49 A | 1.95 A apart | | Dimensions | 2382x1134x30 mm | 2384x1303x33 mm | 2382x1134x30 mm vs 2384x1303x33 mm | ## Every compared parameter | Parameter | TWMNH-66HD645 | TWMHF-66HD740X | | --- | --- | --- | | Rated power | 645 Wp | 740 Wp | | Module efficiency | 23.90 % | 23.80 % | | Power density | 238.8 Wp/m² | 238.2 Wp/m² | | Open-circuit voltage | 49.85 V | 50.62 V | | Voltage at max power | 41.51 V | 42.32 V | | Short-circuit current | 16.39 A | 18.47 A | | Current at max power | 15.54 A | 17.49 A | | Temperature coefficient | -0.280 %/°C | -0.240 %/°C | | Dimensions | 2382x1134x30 mm | 2384x1303x33 mm | | Module area | 2.701 m² | 3.106 m² | | Weight | 32.2 kg | 37.0 kg | | Weight per kWp | 49.9 kg/kWp | 50.0 kg/kWp | | Product warranty | 12 yrs | 15 yrs | | Performance warranty | 30 yrs | 30 yrs | | Annual degradation | 0.40 %/yr | 0.38 %/yr | | Cell technology | N-type | N-type | | 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 - **Cumulative output, TWMNH-66HD645:** 21,641 kWh - **Cumulative output, TWMHF-66HD740X:** 24,925 kWh - **Gap:** 3,284 kWh ## Output when hot | Condition | Cell temperature | TWMNH-66HD645 | TWMHF-66HD740X | Retained | | --- | --- | --- | --- | --- | | Standard test conditions | 25 °C | 645 W | 740 W | 100.0% of rated power | | Cool, bright day | 40 °C | 618 W | 713 W | 95.8% of rated power | | Typical summer roof | 55 °C | 591 W | 687 W | 91.6% of rated power | | Hot roof | 70 °C | 564 W | 660 W | 87.4% of rated power | ## Against the whole database | Measure | TWMNH-66HD645 | TWMHF-66HD740X | Out of | Note | | --- | --- | --- | --- | --- | | Efficiency | #351 | #433 | 14,005 | TWMNH-66HD645 leads by 82 places | | Power density | #356 | #431 | 14,005 | TWMNH-66HD645 leads by 75 places | | Heat behaviour | #1,309 | #13 | 14,005 | TWMHF-66HD740X leads by 1,296 places | | Weight | #3,293 | #3,317 | 14,005 | TWMNH-66HD645 leads by 24 places | | Warranty | #21 | #21 | 14,005 | Tied - the same position in the database | | Overall | #1,342 | #130 | 14,005 | TWMHF-66HD740X leads by 1,212 places | ## Questions ### Which panel is better: Tongwei TWMNH-66HD645 or Tongwei TWMHF-66HD740X? According to our database: **Tongwei TWMNH-66HD645** has higher module efficiency (**23.90%** vs **23.80%**); **Tongwei TWMHF-66HD740X** tolerates heat better (temp coeff **-0.240%/°C** vs **-0.280%/°C**). See the full spec comparison and 30-year energy simulation above for a complete picture. ### What is the efficiency of Tongwei TWMNH-66HD645 and Tongwei TWMHF-66HD740X? **Tongwei TWMNH-66HD645** has a module efficiency of **23.90%**, while **Tongwei TWMHF-66HD740X** is **23.80%**. Higher efficiency means more electricity from the same roof area - useful when space is limited. ### What cell technology does Tongwei TWMNH-66HD645 use vs Tongwei TWMHF-66HD740X? **Tongwei TWMNH-66HD645** uses **N-type** cells; **Tongwei TWMHF-66HD740X** uses **N-type**. 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 TWMNH-66HD645 and Tongwei TWMHF-66HD740X? **Tongwei TWMNH-66HD645** has a **30 years** power warranty; **Tongwei TWMHF-66HD740X** 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 TWMNH-66HD645 and Tongwei TWMHF-66HD740X bifacial panels? Both **Tongwei TWMNH-66HD645** and **Tongwei TWMHF-66HD740X** 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 TWMNH-66HD645 vs Tongwei TWMNF-66HD750](https://comparepv.com/compare/tongwei-solar-twmnh-66hd645/tongwei-solar-twmnf-66hd750) - 8 differences, the largest is rated power - [Tongwei TWMNH-66HD645 vs Tongwei TWMNF-66HD745](https://comparepv.com/compare/tongwei-solar-twmnh-66hd645/tongwei-solar-twmnf-66hd745) - 7 differences, the largest is rated power - [Tongwei TWMNH-66HD645 vs Tongwei TWMNF-66HD740](https://comparepv.com/compare/tongwei-solar-twmnh-66hd645/tongwei-solar-twmnf-66hd740) - 7 differences, the largest is rated power - [Tongwei TWMNH-66HD645 vs Tongwei TWMNF-66HD735](https://comparepv.com/compare/tongwei-solar-twmnh-66hd645/tongwei-solar-twmnf-66hd735) - 8 differences, the largest is rated power - [Tongwei TWMNH-66HD645 vs Tongwei TWMHF-66HD735X](https://comparepv.com/compare/tongwei-solar-twmnh-66hd645/tw-solar-twmhf-66hd735x) - 9 differences, the largest is temperature coefficient - [Tongwei TWMNH-66HD645 vs Tongwei TWMHF-66HD730X](https://comparepv.com/compare/tongwei-solar-twmnh-66hd645/tw-solar-twmhf-66hd730x) - 10 differences, the largest is temperature coefficient --- Source: https://comparepv.com/compare/tongwei-solar-twmnh-66hd645/tw-solar-twmhf-66hd740x 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.