--- title: "Tongwei TNC G12-66 Bifacial 705W Solar Panel - Specs & Review | ComparePV" description: "Tongwei TNC G12-66 Bifacial 705W solar panel. Specs: 22.70% efficiency, Monocrystalline cells, dimensions, warranty and temperature coefficient." source: "https://comparepv.com/panel/tongwei-tnc-g12-66-bifacial" updated: 2026-09-11 --- # Tongwei TNC G12-66 Bifacial Strong in heat, needs the roof space 420 panels in the segment TOPCon 700-750 W ## Identity - **Manufacturer:** Tongwei - **Model:** TNC G12-66 Bifacial - **Series:** TNC Series - **Rated power:** 705 W - **Cell technology:** TOPCon ## How it compares Compared against segment TOPCon 700-750 W (420 panels). | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Power (Wp) | 705 W | 715 W | Weak - bottom 22% | | | Module efficiency | 22.70% | 23.00% | Weak - bottom 23% | 3,307 | | Power density | 227.0 | 230.2 | Weak - bottom 21% | 3,361 | | Temperature coefficient | -0.280 | -0.290 | Strong - top 11% | 1,309 | | Weight (kg) | 37.9 kg | 38.0 kg | Typical | | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | ### Full peer table | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Module efficiency | 22.70% | 23.00% | Weak - bottom 23% | 3,307 | | Power density | 227.0 | 230.2 | Weak - bottom 21% | 3,361 | | Temperature coefficient | -0.280 | -0.290 | Strong - top 11% | 1,309 | | Weight per kWp | 53.8 | 52.9 | Typical | 7,811 | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | ### Strengths - **-0.280 %/°C temperature coefficient** - Top 11% of the TOPCon 700-750 W segment, against a median of -0.290. ### Watch out for - **227.0 watts per square metre** - Bottom 21% of the TOPCon 700-750 W segment, against a median of 230.2. - **22.70% module efficiency** - Bottom 23% of the TOPCon 700-750 W segment, against a median of 23.00%. - **Best for:** Residential, commercial, utility-scale, shaded-installations and hot-climate. - **Not ideal for:** Roofs where every square metre has to count and tight roof space. ## Specification ### Electrical - **Rated power (Pmax):** 705 W - **Efficiency:** 22.70 % - **Voltage at Pmax (Vmp):** 40.52 V - **Current at Pmax (Imp):** 17.40 A - **Open-circuit voltage (Voc):** 48.77 V - **Short-circuit current (Isc):** 18.40 A ### Temperature - **Temperature coefficient of Pmax:** -0.280 %/degC - **Temperature coefficient of Voc:** -0.250 %/degC - **Temperature coefficient of Isc:** 0.046 %/degC - **NOCT:** 45 degC ### Cell and construction - **Cell type:** Monocrystalline - **Cell technology:** TOPCon ### Physical - **Length:** 2384 mm - **Width:** 1303 mm - **Weight:** 37.9 kg - **Area:** 3.11 m2 - **Power density:** 227.0 Wp/m2 ### Warranty and degradation - **Product warranty:** 12 years - **Performance warranty:** 30 years - **Output guaranteed at end of warranty:** 87.4 % - **First-year degradation:** 1.00 % - **Annual degradation:** 0.40 % - **Output after 30 years:** 616 W ## Rank in the whole catalogue | Measure | Position | | --- | --- | | Efficiency | 3307 of 14005 | | Power density | 3361 of 14005 | | Temperature coefficient | 1309 of 14005 | | Weight | 7811 of 14005 | | Warranty | 21 of 14005 | ## About this series The Tongwei TNC Series of solar panels redefines performance standards thanks to proprietary N-type cell technology, which significantly reduces energy losses at the atomic level. The use of **TNC (Tongwei N-type Cell) technology** allows for higher light conversion efficiency compared to conventional TOPCon solutions available on the market. The innovative design based on **SMBB multi-busbar cells** ensures better current flow and minimizes the risk of harmful micro-cracks, which translates into decades of trouble-free operation for the entire system. These panels effectively eliminate the problem of light-induced degradation, offering **exceptional resistance to LID and LeTID phenomena**. Thanks to an excellent temperature coefficient, these modules work significantly more efficiently on hot summer days, generating more energy from the same roof area. This is an ideal solution for investors looking for **maximum yields in difficult lighting conditions**, characteristic of the capricious Polish climate. The Tongwei TNC Series stands out from the competition thanks to full control of the silicon supply chain, guaranteeing the highest material purity and stability of electrical parameters for every module. These products are ideal for both residential micro-installations and demanding commercial projects where the priority is the lowest levelized cost of energy (LCOE). ## Notable figures - Efficiency of 22.7% matches the \*\*TOPCon 700-750W\*\* median - 226.9 W/m² power density is 3.2 W/m² below \*\*TOPCon 700-750W\*\* median (230.2 W/m²) - requires larger installation area - Temperature coefficient of -0.28%/°C matches the \*\*TOPCon 700-750W\*\* median - In the top 24% for efficiency among all TOPCon panels ## Questions ### How much power can Tongwei TNC Series panels with 710 Wp output actually generate? TNC Series panels reach a maximum output of up to 710 Wp thanks to N-type TOPCon cell technology, delivering higher conversion efficiency on the same surface area compared to classic PERC modules. For a typical 6 kWp residential installation, about 8-9 panels are needed, meaningfully reducing the required roof area while keeping the same system capacity. ### What warranty comes with Tongwei TNC Series panels? Tongwei provides a 12-year product warranty and a 30-year linear power output warranty. This covers both manufacturing defects and excessive efficiency loss over time. Tongwei holds Tier 1 manufacturer status, confirming financial stability and a realistic ability to honor warranty claims throughout this entire period. ### Do TNC Series panels perform well on hot summer days? Yes, TNC Series modules feature a favorable temperature coefficient typical of TOPCon technology, limiting power loss at high cell operating temperatures compared to older PERC-based solutions. In practice, this means smaller efficiency drops on hot summer days, when a roof-mounted panel's temperature can significantly exceed ambient temperature. ### How does the N-type TOPCon technology in TNC Series differ from standard PERC panels? The N-type cells used in TNC Series have a purer silicon structure and an additional passivation layer, reducing carrier recombination and energy losses compared to classic P-type PERC cells. The result is higher module efficiency, lower light-induced degradation, and better resistance to LID and LeTID, translating into more stable energy yields throughout the system's lifetime. ### Are Tongwei TNC Series panels resistant to microcracks and mechanical damage? Yes, the design based on multi-busbar SMBB cells spreads current across more connection paths, reducing the risk of microcracks and limiting the impact of a single cell defect on overall panel performance. This construction improves the module's mechanical durability, which matters both during transport and installation and over years of exposure to snow and wind loads on the roof. ### Is the Tongwei TNC Series a bifacial panel? No, this configuration of the TNC Series is a monofacial panel, not bifacial. It generates energy only from irradiance hitting the front side of the module. Customers looking for extra energy gain from light reflected off the ground can ask Tongwei about separate bifacial variants offered in other product series, so it's worth checking availability when placing an order. ## Datasheet [Manufacturer datasheet (PDF)](https://comparepv.com/datasheets/4d0ba6130d9c1c2a59f351d0313e1ae7-b2f06a32fd84.pdf) ## Alternatives | Panel | Power | How it differs | | --- | --- | --- | | [AIKO AIKO-A680-MDE72Mw](https://comparepv.com/panel/aiko-aiko-a680-mde72mw) | 680 W | -25 W, lighter, +2.5 pp | | [AIKO AIKO-A675-MDE72Mw](https://comparepv.com/panel/aiko-aiko-a675-mde72mw) | 675 W | -30 W, lighter, +2.3 pp | | [AIKO AIKO-A700-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a700-mae78dw) | 700 W | Cooler, lighter, +2.3 pp | | [AIKO AIKO-A695-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a695-mae78dw) | 695 W | Cooler, lighter, +2.2 pp | | [AIKO AIKO-G670-MCH72Mw](https://comparepv.com/panel/aiko-aiko-g670-mch72mw) | 670 W | -35 W, lighter, +2.1 pp | | [Longi Solar LR7-72HVHF-670M](https://comparepv.com/panel/longi-lr7-72hvhf-670m) | 670 W | -35 W, lighter, +2.1 pp | | [Jinko Solar JKM650-670N-66QL6-BDV (670W class)](https://comparepv.com/panel/jinko-solar-jkm650-670n-66ql6-bdv-670w-class) | 670 W | -35 W, lighter, +2.1 pp | | [Tongwei TWMPF-66HD655](https://comparepv.com/panel/tw-solar-tongwei-twmpf-66hd655) | 655 W | -50 W, hotter, -1.6 pp | | [Tongwei TWMPF-66HD660](https://comparepv.com/panel/tw-solar-tongwei-twmpf-66hd660) | 660 W | -45 W, hotter, -1.5 pp | | [Tongwei TWMPF-66HD665](https://comparepv.com/panel/tw-solar-tongwei-twmpf-66hd665) | 665 W | -40 W, hotter, -1.3 pp | | [Tongwei TWMPF-66HD670](https://comparepv.com/panel/tw-solar-tongwei-twmpf-66hd670) | 670 W | -35 W, hotter, -1.1 pp | | [Tongwei TWMPF-66HD675](https://comparepv.com/panel/tw-solar-tongwei-twmpf-66hd675) | 675 W | -30 W, hotter, -1.0 pp | | [Tongwei TWMNF-66HD700XX](https://comparepv.com/panel/tw-solar-tongwei-twmnf-66hd700xx) | 700 W | Very close match | | [AIKO AIKO-A805-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a805-grh78dw) | 805 W | +100 W, cooler, +2.4 pp | | [AIKO AIKO-A800-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a800-grh78dw) | 800 W | +95 W, cooler, +2.2 pp | | [AIKO AIKO-A795-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a795-grh78dw) | 795 W | +90 W, cooler, +2.1 pp | --- Source: https://comparepv.com/panel/tongwei-tnc-g12-66-bifacial 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.