--- title: "Tongwei THC G12-66 Bifacial vs Tongwei TWMNF-66HD - Solar Panel Comparison | ComparePV" description: "Compare Tongwei THC G12-66 Bifacial vs Tongwei TWMNF-66HD side by side: what actually differs, output when it is hot, thirty-year production, and the full specification." source: "https://comparepv.com/compare/tongwei-thc-g12-66-bifacial/tongwei-twmnf-66hd" updated: 2026-09-11 --- # Tongwei THC G12-66 Bifacial vs Tongwei TWMNF-66HD THC G12-66 Bifacial leads on the differences that matter The largest is module efficiency: 0.80 pp more efficient. 12 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 | [Tongwei THC G12-66 Bifacial](https://comparepv.com/panel/tongwei-thc-g12-66-bifacial) | [Tongwei TWMNF-66HD](https://comparepv.com/panel/tongwei-twmnf-66hd) | | Manufacturer | Tongwei | Tongwei | | Power | 740 Wp | 715 Wp | | Efficiency | 23.80 % | 23.00 % | | Technology | TOPCon | TOPCon | ## Where they differ Ranked by how much the difference matters, not by datasheet order. | Parameter | THC G12-66 Bifacial | TWMNF-66HD | Difference | | --- | --- | --- | --- | | Module efficiency | 23.80 % | 23.00 % | +0.80 pp for THC G12-66 Bifacial | | Power density | 238.2 Wp/m² | 230.2 Wp/m² | +8.0 Wp/m² for THC G12-66 Bifacial | | Rated power | 740 Wp | 715 Wp | +25 W for THC G12-66 Bifacial | | Weight per kWp | 50.0 kg/kWp | 53.0 kg/kWp | -3.0 kg/kWp for THC G12-66 Bifacial | | Open-circuit voltage | 50.62 V | 49.11 V | 1.51 V apart | | Voltage at max power | 42.32 V | 40.86 V | 1.46 V apart | ## Every compared parameter | Parameter | THC G12-66 Bifacial | TWMNF-66HD | | --- | --- | --- | | Rated power | 740 Wp | 715 Wp | | Module efficiency | 23.80 % | 23.00 % | | Power density | 238.2 Wp/m² | 230.2 Wp/m² | | Open-circuit voltage | 50.62 V | 49.11 V | | Voltage at max power | 42.32 V | 40.86 V | | Short-circuit current | 18.47 A | 18.50 A | | Current at max power | 17.49 A | 17.50 A | | Temperature coefficient | -0.280 %/°C | -0.280 %/°C | | Dimensions | 2384x1303x33 mm | 2384x1303x33 mm | | Module area | 3.106 m² | 3.106 m² | | Weight | 37.0 kg | 37.9 kg | | Weight per kWp | 50.0 kg/kWp | 53.0 kg/kWp | | Product warranty | 15 yrs | 15 yrs | | Performance warranty | 30 yrs | 30 yrs | | Annual degradation | - | - | | 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 (-0.280 %/°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, THC G12-66 Bifacial:** 24,828 kWh - **Cumulative output, TWMNF-66HD:** 23,990 kWh - **Gap:** 838 kWh ## Output when hot | Condition | Cell temperature | THC G12-66 Bifacial | TWMNF-66HD | Retained | | --- | --- | --- | --- | --- | | Standard test conditions | 25 °C | 740 W | 715 W | 100.0% of rated power | | Cool, bright day | 40 °C | 709 W | 685 W | 95.8% of rated power | | Typical summer roof | 55 °C | 678 W | 655 W | 91.6% of rated power | | Hot roof | 70 °C | 647 W | 625 W | 87.4% of rated power | ## Against the whole database | Measure | THC G12-66 Bifacial | TWMNF-66HD | Out of | Note | | --- | --- | --- | --- | --- | | Efficiency | #433 | #1,919 | 14,005 | THC G12-66 Bifacial leads by 1,486 places | | Power density | #431 | #2,018 | 14,005 | THC G12-66 Bifacial leads by 1,587 places | | Heat behaviour | #1,309 | #1,309 | 14,005 | Tied - the same position in the database | | Weight | #3,317 | #6,744 | 14,005 | THC G12-66 Bifacial leads by 3,427 places | | Warranty | #21 | #21 | 14,005 | Tied - the same position in the database | | Overall | #130 | #450 | 14,005 | THC G12-66 Bifacial leads by 320 places | ## Questions ### Which panel is better: Tongwei THC G12-66 Bifacial or Tongwei TWMNF-66HD? According to our database: **Tongwei THC G12-66 Bifacial** has higher module efficiency (**23.80%** vs **23.00%**). See the full spec comparison and 30-year energy simulation above for a complete picture. ### What is the efficiency of Tongwei THC G12-66 Bifacial and Tongwei TWMNF-66HD? **Tongwei THC G12-66 Bifacial** has a module efficiency of **23.80%**, while **Tongwei TWMNF-66HD** is **23.00%**. Higher efficiency means more electricity from the same roof area - useful when space is limited. ### What cell technology does Tongwei THC G12-66 Bifacial use vs Tongwei TWMNF-66HD? **Tongwei THC G12-66 Bifacial** uses **TOPCon** cells; **Tongwei TWMNF-66HD** 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 THC G12-66 Bifacial and Tongwei TWMNF-66HD? **Tongwei THC G12-66 Bifacial** has a **30 years** power warranty; **Tongwei TWMNF-66HD** 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 THC G12-66 Bifacial and Tongwei TWMNF-66HD bifacial panels? Both **Tongwei THC G12-66 Bifacial** and **Tongwei TWMNF-66HD** 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 THC G12-66 Bifacial vs Tongwei TWMNH-66HS](https://comparepv.com/compare/tongwei-thc-g12-66-bifacial/tongwei-twmnh-66hs) - 11 differences, the largest is module efficiency - [Tongwei THC G12-66 Bifacial vs Tongwei TWMNH-66HD](https://comparepv.com/compare/tongwei-thc-g12-66-bifacial/tongwei-twmnh-66hd) - 11 differences, the largest is module efficiency - [Tongwei THC G12-66 Bifacial vs Tongwei TWMNH-54HD](https://comparepv.com/compare/tongwei-thc-g12-66-bifacial/tongwei-twmnh-54hd) - 11 differences, the largest is module efficiency - [Tongwei THC G12-66 Bifacial vs Tongwei TWMNH-48HC](https://comparepv.com/compare/tongwei-thc-g12-66-bifacial/tongwei-twmnh-48hc) - 11 differences, the largest is module efficiency - [Tongwei THC G12-66 Bifacial vs Tongwei TWMNF-66HD750](https://comparepv.com/compare/tongwei-thc-g12-66-bifacial/tongwei-solar-twmnf-66hd750) - 4 differences, the largest is product warranty - [Tongwei THC G12-66 Bifacial vs Tongwei TWMNF-66HD745](https://comparepv.com/compare/tongwei-thc-g12-66-bifacial/tongwei-solar-twmnf-66hd745) - 2 differences, the largest is product warranty --- Source: https://comparepv.com/compare/tongwei-thc-g12-66-bifacial/tongwei-twmnf-66hd 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.