--- title: "Talesun TM8G66M-690 690W Solar Panel - Specs & Review | ComparePV" description: "Talesun TM8G66M-690 690W solar panel. Specs: 22.20% efficiency, Monocrystalline cells, dimensions, warranty and temperature coefficient." source: "https://comparepv.com/panel/talesun-tm8g66m-690" updated: 2026-09-11 --- # Talesun TM8G66M-690 Middle of its segment, heavy for its output 249 panels in the segment TOPCon 650-700 W ## Identity - **Manufacturer:** Talesun - **Model:** TM8G66M-690 - **Series:** TM8G66M (BIPRO) - **Rated power:** 690 W - **Cell technology:** TOPCon - **Bifacial:** yes ## How it compares Compared against segment TOPCon 650-700 W (249 panels). | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Power (Wp) | 690 W | 665 W | Strong - top 21% | | | Module efficiency | 22.20% | 22.40% | Typical | 5,817 | | Power density | 222.1 | 223.7 | Typical | 5,734 | | Temperature coefficient | -0.290 | -0.290 | Typical | 2,165 | | Weight (kg) | 38.5 kg | 34.6 kg | Weak - bottom 24% | | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | ### Full peer table | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Module efficiency | 22.20% | 22.40% | Typical | 5,817 | | Power density | 222.1 | 223.7 | Typical | 5,734 | | Temperature coefficient | -0.290 | -0.290 | Typical | 2,165 | | Weight per kWp | 55.8 | 53.2 | Weak - bottom 24% | 10,180 | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | ### Watch out for - **55.8 kg per kWp** - Bottom 24% of the TOPCon 650-700 W segment, against a median of 53.2. - **Best for:** Utility-scale, commercial and shaded-installations. - **Not ideal for:** Weight-limited structures. ## Specification ### Electrical - **Rated power (Pmax):** 690 W - **Efficiency:** 22.20 % - **Voltage at Pmax (Vmp):** 40.00 V - **Current at Pmax (Imp):** 17.23 A - **Open-circuit voltage (Voc):** 47.90 V - **Short-circuit current (Isc):** 18.25 A - **Max system voltage:** 1500 V ### Temperature - **Temperature coefficient of Pmax:** -0.290 %/degC - **Temperature coefficient of Voc:** -0.240 %/degC - **Temperature coefficient of Isc:** 0.043 %/degC - **NOCT:** 43 degC ### Cell and construction - **Cell type:** Monocrystalline - **Cell technology:** TOPCon - **Cell count:** 132 - **Bifacial:** yes ### Physical - **Length:** 2384 mm - **Width:** 1303 mm - **Thickness:** 33 mm - **Weight:** 38.5 kg - **Area:** 3.11 m2 - **Power density:** 222.1 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:** 603 W ## Rank in the whole catalogue | Measure | Position | | --- | --- | | Efficiency | 5817 of 14005 | | Power density | 5734 of 14005 | | Temperature coefficient | 2165 of 14005 | | Weight | 10180 of 14005 | | Warranty | 21 of 14005 | ## About this series Talesun TM8G66M (BIPRO) series is designed for installations where real energy yield matters more than just paper parameters. The use of **N-type TOPCon double-sided cells** effectively captures sunlight from both sides, translating to higher yields in areas with light backgrounds or good light reflection. Modules utilize **half-cut technology**, enabling better performance during partial shading and offering more stable operation under varying conditions. The 18BB **multi-string structure** also deserves attention, supporting lower losses and better performance in low-light conditions. In practice, this series addresses a common challenge: production drops in poor weather and installations with non-ideal exposure. Thanks to **high PID resistance**, the sealed junction box, and durable construction, it proves ideal for solar farms, industrial rooftops, and demanding locations where dust, moisture, and wind are daily occurrences. ## Notable figures - At 22.2% efficiency, this panel is on par with typical \*\*TOPCon 650-700W\*\* modules - Power density of 222.1 W/m² matches the \*\*TOPCon 650-700W\*\* median - At -0.29%/°C, hot weather performance is typical for \*\*TOPCon 650-700W\*\* panels - Weight of 38.5 kg is 3.9 kg above \*\*TOPCon 650-700W\*\* median (34.6 kg) - verify structural support - 80% bifaciality enables rear-side power generation, boosting yield by 4-12% on reflective surfaces ## Questions ### What warranty comes with the Talesun TM8G66M (BIPRO) series? The TM8G66M (BIPRO) series carries a 12-year product warranty and a 30-year linear power output warranty. This means Talesun covers material and workmanship defects for 12 years, while the guaranteed power degradation curve supports stable energy production over three decades. As a Tier 1 manufacturer, Talesun offers solid backing for these terms in real-world project financing. ### Are Talesun TM8G66M panels bifacial, and is it worth it? Yes, the modules use bifacial N-type TOPCon cells that capture irradiance from both the front and rear side of the panel. The rear-side energy gain depends on the ground surface and mounting height – bright surfaces like gravel, white roofing, or snow give the best results, along with sufficient ground clearance. In typical ground-mount and industrial rooftop installations, this can add several percent extra yield compared to monofacial panels. ### How does N-type TOPCon technology in the TM8G66M differ from older PERC cells? N-type TOPCon cells have lower recombination losses and higher efficiency than the P-type PERC cells commonly used before, resulting in higher module power for the same surface area – up to 710 Wp in this series. TOPCon also resists light- and temperature-induced degradation better, so the panel loses power more slowly over its service life than comparable PERC modules. ### Are TM8G66M (BIPRO) panels suitable for a utility-scale solar farm in harsh conditions? Yes, the series is designed for large ground-mount installations and industrial rooftops exposed to dust, humidity, and strong wind. The sealed junction box protects the electronics from moisture ingress, and high PID resistance prevents power loss at the high system voltages typical of large PV farms. The reinforced frame also ensures mechanical stability under wind and snow loads. ### How do TM8G66M panels handle partial shading from chimneys or poles? Thanks to half-cut cell technology, each cell is split in half and wired into independent circuits, so shading part of the module reduces output only in that shaded segment rather than shutting down the whole panel. In practice this means lower energy losses from partial shading by nearby structures compared to older full-cell panels, which matters on roofs with imperfect sun exposure. ### What benefit does the 18BB multi-busbar design offer in Talesun TM8G66M panels? The 18-busbar layout shortens the current path within each cell, reducing resistive losses and improving performance especially in low-light conditions such as early morning, evening, or overcast days. More, thinner busbars also increase the cell's mechanical resistance to microcracks, contributing to a more stable, longer-lasting panel under demanding operating conditions. ## Datasheet [Manufacturer datasheet (PDF)](https://comparepv.com/datasheets/bipro-tm8g66m-18bb-20240322-en-b2cf93f777d3.pdf) ## Alternatives | Panel | Power | How it differs | | --- | --- | --- | | [AIKO AIKO-A650-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a650-mae72mw) | 650 W | -40 W, lighter, +3.0 pp | | [AIKO AIKO-A680-MDE72Mw](https://comparepv.com/panel/aiko-aiko-a680-mde72mw) | 680 W | Cooler, lighter, +3.0 pp | | [AIKO AIKO-A675-MDE72Mw](https://comparepv.com/panel/aiko-aiko-a675-mde72mw) | 675 W | Cooler, lighter, +2.8 pp | | [AIKO AIKO-A645-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a645-mae72mw) | 645 W | -45 W, lighter, +2.8 pp | | [AIKO AIKO-A700-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a700-mae78dw) | 700 W | Cooler, lighter, +2.8 pp | | [AIKO AIKO-A695-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a695-mae78dw) | 695 W | Cooler, lighter, +2.7 pp | | [AIKO AIKO-G670-MCH72Mw](https://comparepv.com/panel/aiko-aiko-g670-mch72mw) | 670 W | Cooler, lighter, +2.6 pp | | [Talesun TP8F66M-650](https://comparepv.com/panel/talesun-tp8f66m-650) | 650 W | Hotter, -1.3 pp, -5 yr warranty | | [Talesun TP8F66M-655](https://comparepv.com/panel/talesun-tp8f66m-655) | 655 W | Hotter, -1.1 pp, -5 yr warranty | | [Talesun TP8F66M-660](https://comparepv.com/panel/talesun-tp8f66m-660) | 660 W | Hotter, -0.9 pp, -5 yr warranty | | [Talesun TD8G66M/665W](https://comparepv.com/panel/talesun-td8g66m-665w) | 665 W | -25 W, hotter, -0.8 pp | | [Talesun TD8G66M/670W](https://comparepv.com/panel/talesun-td8g66m-670w) | 670 W | -20 W, hotter, -0.6 pp | | [AIKO AIKO-A805-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a805-grh78dw) | 805 W | +115 W, cooler, +2.9 pp | | [AIKO AIKO-A800-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a800-grh78dw) | 800 W | +110 W, cooler, +2.7 pp | | [AIKO AIKO-A795-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a795-grh78dw) | 795 W | +105 W, cooler, +2.6 pp | | [AIKO AIKO-A790-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a790-grh78dw) | 790 W | +100 W, cooler, +2.4 pp | --- Source: https://comparepv.com/panel/talesun-tm8g66m-690 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.