--- title: "Tongwei TWMHF-66HD740X 740W Solar Panel - Specs & Review | ComparePV" description: "Tongwei TWMHF-66HD740X 740W solar panel. Specs: 23.80% efficiency, Monocrystalline cells, dimensions, warranty and temperature coefficient." source: "https://comparepv.com/panel/tw-solar-twmhf-66hd740x" updated: 2026-09-11 --- # Tongwei TWMHF-66HD740X Efficiency leader, no clear weak spot 90 panels in the segment N-type 700-750 W ## Identity - **Manufacturer:** Tongwei - **Model:** TWMHF-66HD740X - **Series:** TWMHF (66HD715–740W) - **Rated power:** 740 W - **Cell technology:** N-type - **Bifacial:** yes ## How it compares Compared against segment N-type 700-750 W (90 panels). | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Power (Wp) | 740 W | 710 W | Strong - top 1% | | | Module efficiency | 23.80% | 22.88% | Strong - top 1% | 433 | | Power density | 238.2 | 228.6 | Strong - top 1% | 431 | | Temperature coefficient | -0.240 | -0.290 | Strong - top 3% | 13 | | Weight (kg) | 37.0 kg | 38.0 kg | Strong - top 14% | | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | ### Full peer table | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Module efficiency | 23.80% | 22.88% | Strong - top 1% | 433 | | Power density | 238.2 | 228.6 | Strong - top 1% | 431 | | Temperature coefficient | -0.240 | -0.290 | Strong - top 3% | 13 | | Weight per kWp | 50.0 | 53.5 | Strong - top 14% | 3,317 | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | ### Strengths - **23.80% module efficiency** - Top 1% of the N-type 700-750 W segment, against a median of 22.88%. Ranked 433rd in the whole database. - **238.2 watts per square metre** - Top 1% of the N-type 700-750 W segment, against a median of 228.6. Ranked 431st in the whole database. - **-0.240 %/°C temperature coefficient** - Top 3% of the N-type 700-750 W segment, against a median of -0.290. Ranked 13th in the whole database. - **Best for:** Commercial, utility-scale and shaded-installations. ## Specification ### Electrical - **Rated power (Pmax):** 740 W - **Efficiency:** 23.80 % - **Voltage at Pmax (Vmp):** 42.32 V - **Current at Pmax (Imp):** 17.49 A - **Open-circuit voltage (Voc):** 50.62 V - **Short-circuit current (Isc):** 18.47 A - **Max system voltage:** 1500 V ### Temperature - **Temperature coefficient of Pmax:** -0.240 %/degC - **Temperature coefficient of Voc:** -0.220 %/degC - **Temperature coefficient of Isc:** 0.040 %/degC - **NOCT:** 44 degC ### Cell and construction - **Cell type:** Monocrystalline - **Cell technology:** N-type - **Cell count:** 132 - **Bifacial:** yes ### Physical - **Length:** 2384 mm - **Width:** 1303 mm - **Thickness:** 33 mm - **Weight:** 37.0 kg - **Area:** 3.11 m2 - **Power density:** 238.2 Wp/m2 ### Warranty and degradation - **Product warranty:** 15 years - **Performance warranty:** 30 years - **Output guaranteed at end of warranty:** 88.1 % - **First-year degradation:** 1.00 % - **Annual degradation:** 0.38 % - **Output after 30 years:** 652 W ## Rank in the whole catalogue | Measure | Position | | --- | --- | | Efficiency | 433 of 14005 | | Power density | 431 of 14005 | | Temperature coefficient | 13 of 14005 | | Weight | 3317 of 14005 | | Warranty | 21 of 14005 | ## About this series The Tongwei TWMHF (66HD715-740W) series is designed to deliver maximum yield from every square meter - where power per module and accelerating project completion matter. The application of **N-type** cells in a **half-cut** architecture helps reduce resistive losses and better withstand partial shading, translating to a more stable performance in variable weather conditions. Modules in this series utilize **bifacial designs**, enabling them to further harness reflected light from the ground - a tangible advantage on flat roofs, PV farms, and structures over light surfaces (e.g., light tiles, light screed). An additional benefit is **low annual power degradation over the long term**, facilitating energy production planning and improving investment bankability. TWMHF 66HD is an excellent choice for installers and investors who wish to reduce the number of modules, simplify the logistical mounting, and maintain high string power without compromising reliability. ## Notable figures - At 23.8% efficiency, this panel is 0.9pp above typical \*\*N-type 700-750W\*\* modules (median: 22.9%) - Power density of 238.2 W/m² packs 9.6 W/m² more into the same footprint vs \*\*N-type 700-750W\*\* median (228.6 W/m²) - Temperature coefficient of -0.24%/°C vs median -0.29%/°C means ~2% less power loss at 65°C - At 37.0 kg, weight matches the \*\*N-type 700-750W\*\* median - Bifacial design (85% factor) captures reflected light - adds 4-13% yield on ground-mount or white roof ## Questions ### What is the maximum efficiency of Tongwei TWMHF 66HD modules and how does it translate to up to 740W output? TWMHF 66HD modules reach efficiency up to 23.00% thanks to N-type TOPCon cells arranged in a half-cut architecture (132 cells in a 6x22 layout). With dimensions of roughly 2384x1303 mm, this allows a single module to deliver up to 740 Wp, meaning fewer modules are needed to reach a target system power and lower mounting structure and installation labor costs. ### How much more energy does a bifacial TWMHF panel produce compared to a standard monofacial module? Thanks to its bifacial design, the module also generates current from its rear side, capturing light reflected off the ground. Depending on surface albedo (light gravel, white roofing membrane, snow), the real-world energy gain can range from a few to over ten percent compared to a comparable monofacial module - bifaciality of N-type cells is typically higher than that of standard P-type cells. ### What warranty comes with Tongwei TWMHF 66HD solar panels? Tongwei, a Tier 1 manufacturer, provides a 15-year product warranty and a 30-year linear power output warranty on this module. This level of coverage and the manufacturer's reputation make it easier to secure project financing (bankability) and to plan long-term energy production from the system throughout its operating life. ### Are TWMHF 66HD panels suitable for large solar farms, or better suited to rooftop installations? Given the high power output of a single module (up to 740 Wp), a weight of about 38 kg, and dimensions of roughly 2384x1303 mm, the TWMHF 66HD series is primarily designed for large ground-mounted, utility-scale PV plants, where minimizing module count and optimizing string configuration matter most. It also works on large flat roofs, provided the mounting structure and installation logistics are properly planned. ### How do TWMHF panels perform in high temperatures and under partial shading? The module has a power temperature coefficient of -0.30%/°C, meaning a smaller power drop as operating temperature rises compared to typical P-type cells, resulting in higher energy yield in summer. The half-cut architecture further splits cells into smaller segments, reducing the impact of partial shading, such as from chimneys or trees, on overall module output. ### Is Tongwei a manufacturer that can be trusted for a large-scale PV investment? Tongwei is a Chinese, Tier 1-rated manufacturer and one of the world's largest suppliers of solar cells and modules, which translates into supply chain stability and reliable access to warranty service. Tier 1 status is also frequently required by banks and insurers when financing PV projects, making it easier to secure a loan for an installation using TWMHF modules. ## Datasheet [Manufacturer datasheet (PDF)](https://comparepv.com/datasheets/4-b1f5d06add29.pdf) ## Alternatives | Panel | Power | How it differs | | --- | --- | --- | | [AIKO AIKO-A700-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a700-mae78dw) | 700 W | -40 W, lighter, +1.2 pp | | [AIKO AIKO-A695-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a695-mae78dw) | 695 W | -45 W, lighter, +1.1 pp | | [AIKO AIKO-A690-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a690-mae78dw) | 690 W | -50 W, lighter, +0.9 pp | | [AIKO AIKO-A790-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a790-grh78dw) | 790 W | +50 W, heavier, +0.8 pp | | [Trina Solar TSM-NEG21C.20Q-760](https://comparepv.com/panel/trina-solar-tsm-neg21c-20q-760) | 760 W | +20 W, hotter, +0.7 pp | | [AIKO AIKO-A785-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a785-grh78dw) | 785 W | +45 W, heavier, +0.6 pp | | [Gokin GK-4-78HGBD-780M](https://comparepv.com/panel/gokin-gk-4-78hgbd-780m) | 780 W | +40 W, hotter, +0.5 pp | | [AIKO AIKO-A780-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a780-grh78dw) | 780 W | +40 W, heavier, +0.5 pp | | [Jetion JT755SLk(B)](https://comparepv.com/panel/jetion-jt755slk-b) | 755 W | +15 W, +0.5 pp | | [Trina Solar TSM-NEG21C.20Q-755](https://comparepv.com/panel/trina-solar-tsm-neg21c-20q-755) | 755 W | +15 W, hotter, +0.5 pp | | [Tongwei TWMPF-66HD655](https://comparepv.com/panel/tw-solar-tongwei-twmpf-66hd655) | 655 W | -85 W, hotter, -2.7 pp | | [Tongwei TWMPF-66HD660](https://comparepv.com/panel/tw-solar-tongwei-twmpf-66hd660) | 660 W | -80 W, hotter, -2.6 pp | | [Tongwei TWMPF-66HD665](https://comparepv.com/panel/tw-solar-tongwei-twmpf-66hd665) | 665 W | -75 W, hotter, -2.4 pp | | [Tongwei TWMPF-66HD670](https://comparepv.com/panel/tw-solar-tongwei-twmpf-66hd670) | 670 W | -70 W, hotter, -2.2 pp | | [Tongwei TWMPF-66HD675](https://comparepv.com/panel/tw-solar-tongwei-twmpf-66hd675) | 675 W | -65 W, hotter, -2.1 pp | | [Tongwei TWMNF-66HD700XX](https://comparepv.com/panel/tw-solar-tongwei-twmnf-66hd700xx) | 700 W | -40 W, hotter, -1.3 pp | | [AIKO AIKO-A805-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a805-grh78dw) | 805 W | +65 W, heavier, +1.3 pp | --- Source: https://comparepv.com/panel/tw-solar-twmhf-66hd740x Not in this file, on the page: the I-V and temperature curves lifted from the manufacturer's datasheet, a thirty-year output simulator, a bifacial gain calculator and alternatives filtered by how closely they match these dimensions.