--- title: "Tongwei TWMPF-66HD665 665W Solar Panel - Specs & Review | ComparePV" description: "Tongwei TWMPF-66HD665 665W solar panel. Specs: 21.40% efficiency, Monocrystalline cells, dimensions, warranty and temperature coefficient." source: "https://comparepv.com/panel/tw-solar-tongwei-twmpf-66hd665" updated: 2026-09-11 --- # Tongwei TWMPF-66HD665 Strong in heat, no clear weak spot 320 panels in the segment PERC 650-700 W ## Identity - **Manufacturer:** Tongwei - **Model:** TWMPF-66HD665 - **Series:** TWMPF - **Rated power:** 665 W - **Cell technology:** PERC - **Bifacial:** yes ## How it compares Compared against segment PERC 650-700 W (320 panels). | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Power (Wp) | 665 W | 660 W | Typical | | | Module efficiency | 21.40% | 21.25% | Typical | 8,323 | | Power density | 214.1 | 212.5 | Typical | 8,250 | | Temperature coefficient | -0.330 | -0.340 | Strong - top 6% | 8,545 | | Weight (kg) | 37.9 kg | 34.5 kg | Typical | | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | ### Full peer table | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Module efficiency | 21.40% | 21.25% | Typical | 8,323 | | Power density | 214.1 | 212.5 | Typical | 8,250 | | Temperature coefficient | -0.330 | -0.340 | Strong - top 6% | 8,545 | | Weight per kWp | 57.0 | 52.3 | Typical | 10,995 | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | ### Strengths - **-0.330 %/°C temperature coefficient** - Top 6% of the PERC 650-700 W segment, against a median of -0.340. Ranked 8,545th in the whole database. - **Best for:** Residential, commercial and shaded-installations. ## Specification ### Electrical - **Rated power (Pmax):** 665 W - **Efficiency:** 21.40 % - **Voltage at Pmax (Vmp):** 38.20 V - **Current at Pmax (Imp):** 17.41 A - **Open-circuit voltage (Voc):** 46.00 V - **Short-circuit current (Isc):** 18.36 A - **Max system voltage:** 1500 V ### Temperature - **Temperature coefficient of Pmax:** -0.330 %/degC - **Temperature coefficient of Voc:** -0.270 %/degC - **Temperature coefficient of Isc:** 0.050 %/degC - **NOCT:** 45 degC ### Cell and construction - **Cell type:** Monocrystalline - **Cell technology:** PERC - **Cell count:** 132 - **Bifacial:** yes - **Bifacial gain:** 25.00 ### Physical - **Length:** 2384 mm - **Width:** 1303 mm - **Thickness:** 33 mm - **Weight:** 37.9 kg - **Area:** 3.11 m2 - **Power density:** 214.1 Wp/m2 ### Warranty and degradation - **Product warranty:** 12 years - **Performance warranty:** 30 years - **Output guaranteed at end of warranty:** 85.0 % - **First-year degradation:** 2.00 % - **Annual degradation:** 0.45 % - **Output after 30 years:** 565 W ## Rank in the whole catalogue | Measure | Position | | --- | --- | | Efficiency | 8323 of 14005 | | Power density | 8250 of 14005 | | Temperature coefficient | 8545 of 14005 | | Weight | 10995 of 14005 | | Warranty | 21 of 14005 | ## About this series The Tongwei TWMPF series utilizes innovative shingled technology, which completely eliminates traditional ribbon connections between cells, replacing them with conductive adhesive. Thanks to this, these modules are characterized by **exceptional resistance to micro-cracks** and significantly lower resistance losses inside the panel. The unique design allows for maximum silicon density, which translates into generating more energy from every square meter of the roof. For the system owner, this means **significantly better performance in partial shading conditions**, as the specific connection layout makes TWMPF panels less sensitive to shadows cast by chimneys, leaves, or satellite dishes. It is a solution dedicated primarily to modern residential buildings, where high aesthetics must go hand in hand with maximum durability. Compared to the competition, this series offers a **deep, uniform design** without visible silver paths, giving the roof surface a luxurious character. Additionally, **reinforced mechanical stability** and lower cell operating temperatures effectively extend the lifespan of the entire system, protecting it from degradation caused by strong winds or accumulated snow. Choosing TWMPF is an investment in stable yields and trouble-free operation for decades, placing this series at the forefront of the most efficient photovoltaic solutions on the Polish market. ## Notable figures - Efficiency of 21.4% matches the \*\*PERC 650-700W\*\* median - At 214.1 W/m² power density, roof space requirements are typical for \*\*PERC 650-700W\*\* panels - Temperature coefficient of -0.33%/°C matches the \*\*PERC 650-700W\*\* median - At 37.9 kg, this panel is 3.4 kg heavier than the \*\*PERC 650-700W\*\* median (34.5 kg) - more demanding for installation crews - Bifaciality factor of 70% can add 4-10% extra yield with reflective mounting surface ## Questions ### Is the Tongwei TWMPF series still available for purchase? No, production of the TWMPF series has been discontinued and these modules are no longer manufactured by Tongwei. Some distributors may still offer remaining warehouse stock, but availability is limited. Anyone planning a larger installation should be aware that matching additional identical modules later on may not be possible and should consider Tongwei's current lineup, such as its TOPCon series. ### What is the shingled cell technology used in TWMPF panels, and how does it differ from standard solder-ribbon cells? In shingled technology, cells are cut into narrower strips and overlapped, bonded together with conductive adhesive instead of traditional solder ribbons connecting whole cells. This eliminates the mechanical stress at solder joints that is a primary cause of microcracks in conventional modules. It also allows for denser packing of silicon on the panel surface, increasing the power output per unit of roof area. ### Are Tongwei TWMPF panels with up to 675 Wp suitable for a residential pitched roof? TWMPF panels are large-format modules, roughly 2384x1303 mm and about 38 kg, designed primarily for commercial, industrial, and utility-scale PV installations rather than typical residential sloped roofs. Their size and weight require a reinforced roof structure and specialized installation, making them better suited to large flat rooftops or ground-mounted systems than a standard family home. ### What warranty applies to Tongwei TWMPF series solar panels? TWMPF panels come with a 12-year product warranty covering material and workmanship defects, along with a 30-year linear power output warranty ensuring high performance over decades of operation. This is standard for a tier 1 manufacturer, though since production has ended, warranty claims in practice may need to be handled through local distributors rather than directly with the factory. ### What does it mean that TWMPF panels are bifacial, and how much extra energy does this generate? Bifacial TWMPF modules use a double-glass rear surface that lets light pass through and reach the back of the cells. This allows the panel to capture light reflected off the ground, such as light gravel, snow, or a white roof, generating a few to several percent more energy compared to a monofacial module, provided the installation allows light access to the rear side. ### What cell technology delivers up to 675 Wp in Tongwei TWMPF panels, and is it PERC-based? Yes, the TWMPF series uses PERC silicon cells connected via the shingled method instead of conventional ribbons. Combining rear-surface passivation with dense cell packing allowed the series to reach up to 675 Wp with high module efficiency, placing it among the more powerful PERC-based options on the market at the time of its release. ## Datasheet [Manufacturer datasheet (PDF)](https://comparepv.com/datasheets/twmpf-66hd655-675w-42b1185c0f46.pdf) ## Alternatives | Panel | Power | How it differs | | --- | --- | --- | | [AIKO AIKO-A650-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a650-mae72mw) | 650 W | Cooler, lighter, +3.8 pp | | [AIKO AIKO-A680-MDE72Mw](https://comparepv.com/panel/aiko-aiko-a680-mde72mw) | 680 W | Cooler, lighter, +3.8 pp | | [AIKO AIKO-A675-MDE72Mw](https://comparepv.com/panel/aiko-aiko-a675-mde72mw) | 675 W | Cooler, lighter, +3.6 pp | | [AIKO AIKO-A645-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a645-mae72mw) | 645 W | Cooler, lighter, +3.6 pp | | [AIKO AIKO-A700-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a700-mae78dw) | 700 W | +35 W, cooler, +3.6 pp | | [AIKO AIKO-A695-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a695-mae78dw) | 695 W | Cooler, lighter, +3.5 pp | | [AIKO AIKO-G670-MCH72Mw](https://comparepv.com/panel/aiko-aiko-g670-mch72mw) | 670 W | Cooler, lighter, +3.4 pp | | [Tongwei TWMPF-66HD655](https://comparepv.com/panel/tw-solar-tongwei-twmpf-66hd655) | 655 W | -10 W, -0.3 pp | | [Tongwei TWMPF-66HD660](https://comparepv.com/panel/tw-solar-tongwei-twmpf-66hd660) | 660 W | Very close match | | [Tongwei TWMPF-66HD670](https://comparepv.com/panel/tw-solar-tongwei-twmpf-66hd670) | 670 W | +0.2 pp | | [Tongwei TWMPF-66HD675](https://comparepv.com/panel/tw-solar-tongwei-twmpf-66hd675) | 675 W | +10 W, +0.3 pp | | [Tongwei TWMNF-66HD700XX](https://comparepv.com/panel/tw-solar-tongwei-twmnf-66hd700xx) | 700 W | +35 W, cooler, +1.1 pp | | [Tongwei TWMNF-66HD705](https://comparepv.com/panel/tongwei-solar-twmnf-66hd705) | 705 W | +40 W, cooler, +1.3 pp | | [AIKO AIKO-A805-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a805-grh78dw) | 805 W | +140 W, cooler, +3.7 pp | | [AIKO AIKO-A800-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a800-grh78dw) | 800 W | +135 W, cooler, +3.5 pp | | [AIKO AIKO-A795-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a795-grh78dw) | 795 W | +130 W, cooler, +3.4 pp | --- Source: https://comparepv.com/panel/tw-solar-tongwei-twmpf-66hd665 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.