--- title: "Trina Solar TSM-DEG21C.20-645 645W Solar Panel - Specs & Review | ComparePV" description: "Trina Solar TSM-DEG21C.20-645 645W solar panel. Specs: 20.80% efficiency, Monocrystalline cells, dimensions, warranty and temperature coefficient." source: "https://comparepv.com/panel/trina-solar-co-ltd-tsm-deg21c-20-645" updated: 2026-09-11 --- # Trina Solar TSM-DEG21C.20-645 Middle of its segment, needs the roof space 217 panels in the segment PERC 600-650 W ## Identity - **Manufacturer:** Trina Solar - **Model:** TSM-DEG21C.20-645 - **Series:** Vertex TSM-DEG21C.20 645-665W - **Rated power:** 645 W - **Cell technology:** PERC - **Bifacial:** yes ## How it compares Compared against segment PERC 600-650 W (217 panels). | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Power (Wp) | 645 W | 605 W | Strong - top 7% | | | Module efficiency | 20.80% | 21.38% | Weak - bottom 18% | 10,457 | | Power density | 207.6 | 213.8 | Weak - bottom 12% | 10,562 | | Temperature coefficient | -0.340 | -0.340 | Typical | 8,778 | | Weight (kg) | 38.3 kg | 34.0 kg | Weak - bottom 13% | | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | ### Full peer table | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Module efficiency | 20.80% | 21.38% | Weak - bottom 18% | 10,457 | | Power density | 207.6 | 213.8 | Weak - bottom 12% | 10,562 | | Temperature coefficient | -0.340 | -0.340 | Typical | 8,778 | | Weight per kWp | 59.4 | 55.7 | Weak - bottom 13% | 12,126 | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | ### Watch out for - **207.6 watts per square metre** - Bottom 12% of the PERC 600-650 W segment, against a median of 213.8. - **59.4 kg per kWp** - Bottom 13% of the PERC 600-650 W segment, against a median of 55.7. - **20.80% module efficiency** - Bottom 18% of the PERC 600-650 W segment, against a median of 21.38%. - **Best for:** Utility-scale and commercial. - **Not ideal for:** Roofs where every square metre has to count, weight-limited structures and tight roof space. ## Specification ### Electrical - **Rated power (Pmax):** 645 W - **Efficiency:** 20.80 % - **Voltage at Pmax (Vmp):** 37.50 V - **Current at Pmax (Imp):** 17.23 A - **Open-circuit voltage (Voc):** 45.30 V - **Short-circuit current (Isc):** 18.31 A - **Max system voltage:** 1500 V ### Temperature - **Temperature coefficient of Pmax:** -0.340 %/degC - **Temperature coefficient of Voc:** -0.250 %/degC - **Temperature coefficient of Isc:** 0.040 %/degC - **NOCT:** 43 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:** 38.3 kg - **Area:** 3.11 m2 - **Power density:** 207.6 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:** 548 W ## Rank in the whole catalogue | Measure | Position | | --- | --- | | Efficiency | 10457 of 14005 | | Power density | 10562 of 14005 | | Temperature coefficient | 8778 of 14005 | | Weight | 12126 of 14005 | | Warranty | 21 of 14005 | ## About this series Trina Solar's Vertex TSM-DEG21C.20 645-665W series is designed specifically for maximizing energy yield in large-scale installations, where every square meter and every hour of the installation team's work matters. The modules utilize monocrystalline wafers in a large-format architecture and **high-density interconnection technology**, which translates to better light utilization even under low irradiance and on cloudy days. The key advantage of this series is the **low-voltage, high-power string concept** - it simplifies string configuration design, making equipment selection easier and reducing the cost of Balance of System (BOS) components. In practice, this means simpler PV farm design and greater system performance predictability. Vertex DEG21C.20 also boasts **enhanced resistance to microcracks** thanks to precise cutting methods and **increased reliability in challenging conditions** (e.g., high humidity, salinity, dust). This makes it an excellent choice for utility-scale solar farms, commercial and industrial installations, and tracker projects where stable performance and longevity are essential. ## Notable figures - Efficiency of 20.8% is 0.6pp below the \*\*PERC 600-650W\*\* median (21.4%) - Power density of 207.6 W/m² is 6.2 W/m² below \*\*PERC 600-650W\*\* median (213.8 W/m²) - needs more roof space - Temperature coefficient of -0.34%/°C matches the \*\*PERC 600-650W\*\* median - Weight of 38.3 kg is 4.3 kg above \*\*PERC 600-650W\*\* median (34.0 kg) - verify structural support - Bifaciality factor of 70% can add 4-10% extra yield with reflective mounting surface ## Questions ### What warranty comes with the Trina Solar Vertex TSM-DEG21C.20 645-665W series? The series carries a 12-year product warranty and a 30-year power output warranty. This means Trina Solar commits to repairing or replacing modules with manufacturing defects for 12 years, while guaranteeing a defined performance level for 30 years. This is one of the longer warranty periods on the market, reducing investment risk for large-scale installations. ### Do the bifacial DEG21C.20 modules require special mounting structures? Bifacial modules in this series perform best on structures that allow light reflection onto the rear side, such as trackers, ground-mount systems raised above the surface, or light-colored ground (gravel, white roofing). No dedicated clamps are required, but leaving minimum clearance under the panel and avoiding dark, absorptive surfaces helps maximize the extra rear-side energy gain. ### What is the low-voltage, higher-power-string concept behind Vertex DEG21C.20? Thanks to higher per-module power (up to 665 Wp), a string of the same total capacity can be built from fewer panels while keeping voltage within a safe range for typical inverters. This means fewer connectors, shorter DC cabling, and simpler PV plant design, lowering balance-of-system (BoS) costs and reducing installation time on large projects. ### Is PERC cell technology in the Vertex DEG21C.20 outdated compared to TOPCon? PERC remains a proven, mature technology with a strong price-to-performance ratio, though newer TOPCon cells offer slightly higher efficiency and slower annual degradation. For large commercial installations, PV farms, and tracker-based projects where predictable cost and stable supply matter most, the PERC-based Vertex DEG21C.20 series remains a solid, competitive choice, especially at high purchase volumes. ### What types of installations is the Trina Vertex TSM-DEG21C.20 645-665W series best suited for? This series is designed for large-scale projects: solar farms, commercial and industrial rooftops, and single-axis tracker installations. The large module format and high unit power up to 665 Wp reduce the number of panels needed per megawatt, shortening installation crew time and lowering mounting structure costs compared to smaller residential modules. ### Does Trina Solar's Tier 1 status add extra security for investors? Yes, Trina Solar is a China-based manufacturer classified as Tier 1, reflecting long-term financial stability, large-scale production capacity, and a track record of honoring warranties. For investors in commercial installations and PV farms, this lowers the risk of the manufacturer exiting the market before the 30-year power warranty expires and ensures easier access to service and replacement parts. ## Datasheet [Manufacturer datasheet (PDF)](https://comparepv.com/datasheets/dt-m-0013-c-datasheet-vertex-deg21c-20-en-2024-a-7dde542c2ab6.pdf) ## Alternatives | Panel | Power | How it differs | | --- | --- | --- | | [AIKO AIKO-A650-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a650-mae72mw) | 650 W | Cooler, lighter, +4.4 pp | | [AIKO AIKO-A680-MDE72Mw](https://comparepv.com/panel/aiko-aiko-a680-mde72mw) | 680 W | Cooler, lighter, +4.4 pp | | [AIKO AIKO-A675-MDE72Mw](https://comparepv.com/panel/aiko-aiko-a675-mde72mw) | 675 W | Cooler, lighter, +4.2 pp | | [AIKO AIKO-A645-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a645-mae72mw) | 645 W | Cooler, lighter, +4.2 pp | | [AIKO AIKO-A695-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a695-mae78dw) | 695 W | +50 W, cooler, +4.1 pp | | [AIKO AIKO-G670-MCH72Mw](https://comparepv.com/panel/aiko-aiko-g670-mch72mw) | 670 W | Cooler, lighter, +4.0 pp | | [Longi Solar LR7-72HVHF-670M](https://comparepv.com/panel/longi-lr7-72hvhf-670m) | 670 W | Cooler, lighter, +4.0 pp | | [Trina Solar TSM-DEG21C.20-650](https://comparepv.com/panel/trina-solar-co-ltd-tsm-deg21c-20-650) | 650 W | Very close match | | [Trina Solar TSM-DE21-655W](https://comparepv.com/panel/trina-solar-co-ltd-tsm-de21-655w) | 655 W | Lighter, +0.3 pp, -5 yr warranty | | [Trina Solar TSM-DE21-660W](https://comparepv.com/panel/trina-solar-co-ltd-tsm-de21-660w) | 660 W | Lighter, +0.4 pp, -5 yr warranty | | [Trina Solar TSM-DE21-665W](https://comparepv.com/panel/trina-solar-co-ltd-tsm-de21-665w) | 665 W | Lighter, +0.6 pp, -5 yr warranty | | [Trina Solar TSM-DE21-670W](https://comparepv.com/panel/trina-solar-co-ltd-tsm-de21-670w) | 670 W | Lighter, +0.7 pp, -5 yr warranty | | [Trina Solar TSM-DE21-675W](https://comparepv.com/panel/trina-solar-co-ltd-tsm-de21-675w) | 675 W | Lighter, +0.9 pp, -5 yr warranty | | [AIKO AIKO-A805-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a805-grh78dw) | 805 W | +160 W, cooler, +4.3 pp | | [AIKO AIKO-A800-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a800-grh78dw) | 800 W | +155 W, cooler, +4.1 pp | | [AIKO AIKO-A795-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a795-grh78dw) | 795 W | +150 W, cooler, +4.0 pp | --- Source: https://comparepv.com/panel/trina-solar-co-ltd-tsm-deg21c-20-645 Not in this file, on the page: a thirty-year output simulator, a bifacial gain calculator and alternatives filtered by how closely they match these dimensions.