--- title: "Tongwei TWMNH-66HD620 620W Solar Panel - Specs & Review | ComparePV" description: "Tongwei TWMNH-66HD620 620W solar panel: 2 shop offers from 99.43 €. Specs: 23.00% efficiency, Monocrystalline cells." source: "https://comparepv.com/panel/tongwei-solar-twmnh-66hd620" updated: 2026-10-04 --- # Tongwei TWMNH-66HD620 Strong in heat, no clear weak spot 1,086 panels in the segment TOPCon 600-650 W ## Identity - **Manufacturer:** Tongwei - **Model:** TWMNH-66HD620 - **Series:** TWMNH (66HD) - **Rated power:** 620 W - **Cell technology:** TOPCon - **Bifacial:** yes ## Price offers Prices are the figure each shop printed, on that shop's side of VAT. | Shop | Market | Price | Per kWp | Availability | Last read | | --- | --- | --- | --- | --- | --- | | [pvshop.eu](https://comparepv.com/go/15468) | Germany | 99.43 € net | 160.37 €/kWp | In stock | Last read 4 Oct 02:05 | | [AZ Solar Shop](https://comparepv.com/go/538599) | Italy | | | Not stated | Last read 4 Oct 02:15 | ## How it compares Compared against segment TOPCon 600-650 W (1086 panels). | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Power (Wp) | 620 W | 620 W | Typical | | | Module efficiency | 23.00% | 22.80% | Typical | 1,919 | | Power density | 229.5 | 227.7 | Typical | 2,191 | | Temperature coefficient | -0.280 | -0.290 | Strong - top 7% | 1,309 | | Weight (kg) | 32.5 kg | 32.7 kg | Typical | | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | ### Full peer table | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Module efficiency | 23.00% | 22.80% | Typical | 1,919 | | Power density | 229.5 | 227.7 | Typical | 2,191 | | Temperature coefficient | -0.280 | -0.290 | Strong - top 7% | 1,309 | | Weight per kWp | 52.4 | 53.1 | Typical | 5,893 | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | ### Strengths - **-0.280 %/°C temperature coefficient** - Top 7% of the TOPCon 600-650 W segment, against a median of -0.290. Ranked 1,309th in the whole database. - **Best for:** Utility-scale, commercial and hot-climate. ## Specification ### Electrical - **Rated power (Pmax):** 620 W - **Efficiency:** 23.00 % - **Voltage at Pmax (Vmp):** 40.82 V - **Current at Pmax (Imp):** 15.19 A - **Open-circuit voltage (Voc):** 49.10 V - **Short-circuit current (Isc):** 16.06 A - **Max system voltage:** 1500 V ### Temperature - **Temperature coefficient of Pmax:** -0.280 %/degC - **Temperature coefficient of Voc:** -0.240 %/degC - **Temperature coefficient of Isc:** 0.046 %/degC - **NOCT:** 45 degC ### Cell and construction - **Cell type:** Monocrystalline - **Cell technology:** TOPCon - **Cell count:** 132 - **Bifacial:** yes - **Bifacial gain:** 25.00 ### Physical - **Length:** 2382 mm - **Width:** 1134 mm - **Thickness:** 30 mm - **Weight:** 32.5 kg - **Area:** 2.70 m2 - **Power density:** 229.5 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:** 542 W ## Rank in the whole catalogue | Measure | Position | | --- | --- | | Efficiency | 1919 of 14005 | | Power density | 2191 of 14005 | | Temperature coefficient | 1309 of 14005 | | Weight | 5893 of 14005 | | Warranty | 21 of 14005 | ## About this series The Tongwei TWMNH (66HD) panel series introduces a new quality to the PV sector, based on innovative N-type cell architecture. The use of **TOPCon technology** allows for significantly higher conversion efficiency, which directly solves the problem of limited installation space while meeting high power demands. These modules stand out with their **bifacial double-glass design**, which provides not only additional energy yield from the rear of the cell but, primarily, the highest resistance to demanding external factors such as ammonia or salt mist. Unlike standard products, the TWMNH series guarantees **exceptionally low power degradation** over the long term, translating into a more stable return on investment for owners of solar farms and large industrial facilities. A key technological element is the **SMBB busbar system**, which optimizes electron flow and increases the resistance of the cells to mechanical loads caused by snow or strong wind. This solution is dedicated to investors who prioritize durability and strive to achieve the lowest LCOE. Thanks to the optimization of the 66HD format, these panels offer an ideal balance between dimensions and yield, outperforming the competition in terms of stability at high temperatures, making them the **most effective choice** for modern solar energy in Poland. ## Notable figures - At 23.0% efficiency, this panel is on par with typical \*\*TOPCon 600-650W\*\* modules - Power density of 229.5 W/m² matches the \*\*TOPCon 600-650W\*\* median - At -0.28%/°C, hot weather performance is typical for \*\*TOPCon 600-650W\*\* panels - Bifacial design (80% factor) captures reflected light - adds 4-12% yield on ground-mount or white roof - In the top 14% for efficiency among all TOPCon panels ## Questions ### What is TOPCon cell technology used in Tongwei TWMNH (66HD) panels and how does it differ from PERC? TOPCon is an N-type cell technology with an additional tunnel oxide passivation layer that reduces electron recombination and raises conversion efficiency compared to older PERC cells. In practice this means higher power output from the same panel area (up to 630 Wp), better performance at high temperatures, and lower annual degradation. For investors this translates into fewer modules needed to reach the target installed capacity. ### What does the double-glass bifacial design of the TWMNH 66HD panels offer? The dual-glass construction and active rear side allow extra energy yield from reflected light, especially on bright surfaces such as gravel, white roofing, or snow, potentially boosting output by several to over a dozen percent. The double-glass design is also far more resistant to ammonia, salt mist, and humidity than a standard backsheet panel, making it well suited to livestock farms, coastal installations, and large PV farms. ### What warranty comes with the Tongwei TWMNH (66HD) series? The manufacturer offers a 12-year product warranty and a 30-year power performance warranty, guaranteeing 87.4% of nominal power after 30 years of operation. First-year degradation is capped at 1%, followed by roughly 0.4% per year thereafter. Tongwei is a Tier 1 manufacturer, which further reduces the risk of warranty servicing issues over the long term. ### What types of installations are Tongwei TWMNH 630 Wp panels best suited for? Given their dimensions of 2382×1134 mm and weight of 32.5 kg, these panels are primarily intended for large ground-mounted installations, solar farms, and industrial sites where minimizing LCOE per megawatt matters most. The high per-module power output reduces the number of panels, cabling, and mounting structure needed to build an installation of a given capacity. ### What is the SMBB busbar system and how does it improve the durability of TWMNH panels? SMBB (Super Multi Busbar) uses many thin busbars across the cell surface instead of a few wide ones, distributing current more evenly and reducing resistive losses. It also increases cell resistance to microcracks caused by mechanical stress. As a result, TWMNH panels withstand snow loads up to 5400 Pa and wind loads up to 2400 Pa, making them suitable for regions with demanding weather conditions. ### How fast does the power output of Tongwei TWMNH panels decline over time? The panels feature low linear degradation: up to 1% power loss in the first year, followed by roughly 0.4% annually thereafter. After 30 years of operation the manufacturer guarantees at least 87.4% of initial power output. This rate outperforms standard P-type cell panels, resulting in more stable and predictable revenue from the installation over its full service life. ## Datasheet [Manufacturer datasheet (PDF)](https://comparepv.com/datasheets/TWMNH-66HD-61063030F-09b64f8638eb.pdf) ## Alternatives | Panel | Power | How it differs | | --- | --- | --- | | [AIKO AIKO-A650-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a650-mae72mw) | 650 W | +30 W, lighter, +2.2 pp | | [AIKO AIKO-A645-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a645-mae72mw) | 645 W | +25 W, lighter, +2.0 pp | | [AIKO AIKO-G670-MCH72Mw](https://comparepv.com/panel/aiko-aiko-g670-mch72mw) | 670 W | +50 W, lighter, +1.8 pp | | [Longi Solar LR7-72HVHF-670M](https://comparepv.com/panel/longi-lr7-72hvhf-670m) | 670 W | +50 W, lighter, +1.8 pp | | [AIKO AIKO-A640-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a640-mae72mw) | 640 W | Cooler, lighter, +1.8 pp | | [Jinko Solar JKM650-670N-66QL6-BDV (670W class)](https://comparepv.com/panel/jinko-solar-jkm650-670n-66ql6-bdv-670w-class) | 670 W | +50 W, cooler, +1.8 pp | | [Tongwei TWMNH-48HC](https://comparepv.com/panel/tongwei-twmnh-48hc) | 450 W | -170 W, lighter, -6.3 pp | | [Tongwei TWMNH-54HD](https://comparepv.com/panel/tongwei-twmnh-54hd) | 515 W | -105 W, lighter, -3.9 pp | | [Tongwei TWMNH-66HD600](https://comparepv.com/panel/tongwei-twmnh-66hd600) | 600 W | -20 W, -0.8 pp | | [Tongwei TWMNH-66HD605](https://comparepv.com/panel/tongwei-twmnh-66hd605) | 605 W | -15 W, -0.6 pp | | [Tongwei TWMNH-66HD610](https://comparepv.com/panel/tongwei-solar-twmnh-66hd610) | 610 W | -10 W, -0.4 pp | | [Tongwei TWMNH-66HD615](https://comparepv.com/panel/tongwei-solar-twmnh-66hd615) | 615 W | Very close match | | [AIKO AIKO-A680-MDE72Mw](https://comparepv.com/panel/aiko-aiko-a680-mde72mw) | 680 W | +60 W, lighter, +2.2 pp | | [AIKO AIKO-A675-MDE72Mw](https://comparepv.com/panel/aiko-aiko-a675-mde72mw) | 675 W | +55 W, lighter, +2.0 pp | | [AIKO AIKO-A700-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a700-mae78dw) | 700 W | +80 W, cooler, +2.0 pp | | [AIKO AIKO-A695-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a695-mae78dw) | 695 W | +75 W, cooler, +1.9 pp | --- Source: https://comparepv.com/panel/tongwei-solar-twmnh-66hd620 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.