--- title: "S-Energy SL85-66BDL-655R 655W Solar Panel - Specs & Review | ComparePV" description: "S-Energy SL85-66BDL-655R 655W solar panel. Specs: 21.11% efficiency, Monocrystalline cells, dimensions, warranty and temperature coefficient." source: "https://comparepv.com/panel/s-energy-sl85-66bdl-655r" updated: 2026-09-11 --- # S-Energy SL85-66BDL-655R Solid all-round for its segment 320 panels in the segment PERC 650-700 W ## Identity - **Manufacturer:** S-Energy - **Model:** SL85-66BDL-655R - **Series:** SL85-66BDL - **Rated power:** 655 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) | 655 W | 660 W | Weak - bottom 25% | | | Module efficiency | 21.11% | 21.25% | Typical | 9,271 | | Power density | 211.1 | 212.5 | Typical | 9,280 | | Temperature coefficient | -0.340 | -0.340 | Typical | 8,778 | | 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 | 21.11% | 21.25% | Typical | 9,271 | | Power density | 211.1 | 212.5 | Typical | 9,280 | | Temperature coefficient | -0.340 | -0.340 | Typical | 8,778 | | Weight per kWp | 57.9 | 52.3 | Typical | 11,461 | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | - **Best for:** Commercial and utility-scale. ## Specification ### Electrical - **Rated power (Pmax):** 655 W - **Efficiency:** 21.11 % - **Voltage at Pmax (Vmp):** 37.62 V - **Current at Pmax (Imp):** 17.41 A - **Open-circuit voltage (Voc):** 46.16 V - **Short-circuit current (Isc):** 18.32 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:** 45 degC ### Cell and construction - **Cell type:** Monocrystalline - **Cell technology:** PERC - **Cell count:** 66 - **Bifacial:** yes - **Bifacial gain:** 25.00 ### Physical - **Length:** 2383 mm - **Width:** 1302 mm - **Thickness:** 35 mm - **Weight:** 37.9 kg - **Area:** 3.10 m2 - **Power density:** 211.1 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:** 556 W ## Rank in the whole catalogue | Measure | Position | | --- | --- | | Efficiency | 9271 of 14005 | | Power density | 9280 of 14005 | | Temperature coefficient | 8778 of 14005 | | Weight | 11461 of 14005 | | Warranty | 21 of 14005 | ## About this series The S-Energy SL85-66BDL series are modules designed for installations where high energy production from a given area and resistance to harsh operating conditions are crucial. The use of a **bifacial design** allows not only direct sunlight to be utilized, but also reflected light from the ground, which significantly improves energy yields in ground-mounted and roof-mounted installations with light-colored surfaces. The **dual glass** variant (glass-glass) enhances operational stability over time, reduces the risk of degradation, and better protects the cells from moisture and micro-cracks, which is important in the Polish climate. The SL85-66BDL is based on **monocrystalline PERC technology**, which provides a good balance between efficiency and predictable performance under varying sunlight conditions. This makes it a suitable choice for investors who want to build installations with a long lifespan, minimizing the risk of performance losses. The series also features a **long power warranty**, which facilitates investment planning in commercial and industrial projects. ## Notable figures - At 21.1% efficiency, this panel is on par with typical \*\*PERC 650-700W\*\* modules - At 211.1 W/m² power density, roof space requirements are typical for \*\*PERC 650-700W\*\* panels - At -0.34%/°C, hot weather performance is typical for \*\*PERC 650-700W\*\* panels - Weight of 37.9 kg is 3.4 kg above \*\*PERC 650-700W\*\* median (34.5 kg) - verify structural support - Bifaciality factor of 70% can add 4-10% extra yield with reflective mounting surface ## Questions ### What is the maximum power output and efficiency of the S-Energy SL85-66BDL panel? The S-Energy SL85-66BDL reaches a peak power of 665 Wp with module efficiency up to 21.43%. The series spans from 645 to 665 Wp, allowing precise sizing for each project. This efficiency level — high for PERC technology — means more energy can be harvested from the same roof or ground area compared to standard monocrystalline modules of an older generation. ### What does the bifacial design mean in the SL85-66BDL series, and when does it actually pay off? A bifacial module generates power from both the front and rear surfaces. In the SL85-66BDL, the rear side captures light reflected from the ground (albedo), boosting annual energy yield — especially in ground-mounted systems with light-colored substrates, white gravel, or snow cover. Depending on ground albedo, the bifacial gain can add several percentage points to annual production compared to a monofacial equivalent. ### What warranty does the S-Energy SL85-66BDL come with? S-Energy provides a 12-year product warranty covering manufacturing defects and a 30-year linear power warranty. After 30 years, the module is guaranteed to retain at least 84.95% of its rated output. The extended power warranty simplifies yield forecasting and supports financing models for commercial and industrial PV projects. ### Do the S-Energy SL85-66BDL panels perform well in winter and in variable weather conditions? Yes. The dual-glass (glass-glass) construction protects cells more effectively against moisture ingress, frost, and microcracks than standard backsheet designs — an important advantage in Central European climates. The PERC cell technology maintains predictable performance under diffuse irradiance, common during autumn and winter. The temperature coefficient of Pmax is -0.34%/°C, indicating moderate power loss at elevated summer temperatures. ### What types of installations are the S-Energy SL85-66BDL modules best suited for? The SL85-66BDL series is primarily designed for utility-scale ground-mounted PV farms and large commercial or industrial flat-roof systems. The module's large footprint (2383 × 1302 mm) and weight of 37.9 kg require robust mounting structures, making it less suitable for small residential pitched roofs. The bifacial gain is best realized where the rear side of the module has unobstructed access to reflected light. ### Is S-Energy a Tier 1 manufacturer, and is it worth investing in? S-Energy is a South Korean solar panel manufacturer with a long track record in the industry; however, it is not currently listed as a Tier 1 manufacturer by financial advisory agencies. For projects requiring project financing, it is advisable to confirm the brand's acceptability with the lending institution in advance. From a technical standpoint, the SL85-66BDL offers strong performance specs and generous warranty terms, which are key factors when evaluating long-term reliability. ## Datasheet [Manufacturer datasheet (PDF)](https://comparepv.com/datasheets/datasheet-sl85-66bdl-xxxr-645-665-231120-2023-en-ver-1-0-0447a19ce435.pdf) ## Alternatives | Panel | Power | How it differs | | --- | --- | --- | | [AIKO AIKO-A650-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a650-mae72mw) | 650 W | Cooler, lighter, +4.1 pp | | [AIKO AIKO-A680-MDE72Mw](https://comparepv.com/panel/aiko-aiko-a680-mde72mw) | 680 W | Cooler, lighter, +4.1 pp | | [AIKO AIKO-A675-MDE72Mw](https://comparepv.com/panel/aiko-aiko-a675-mde72mw) | 675 W | Cooler, lighter, +3.9 pp | | [AIKO AIKO-A645-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a645-mae72mw) | 645 W | Cooler, lighter, +3.9 pp | | [AIKO AIKO-A700-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a700-mae78dw) | 700 W | +45 W, cooler, +3.9 pp | | [AIKO AIKO-A695-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a695-mae78dw) | 695 W | +40 W, cooler, +3.8 pp | | [AIKO AIKO-G670-MCH72Mw](https://comparepv.com/panel/aiko-aiko-g670-mch72mw) | 670 W | Cooler, lighter, +3.7 pp | | [S-Energy SL85-66BDL-645R](https://comparepv.com/panel/s-energy-sl85-66bdl-645r) | 645 W | -10 W, -0.3 pp | | [S-Energy SL85-66BDL-650R](https://comparepv.com/panel/s-energy-sl85-66bdl-650r) | 650 W | Very close match | | [S-Energy SL85-66BDL-660R](https://comparepv.com/panel/s-energy-sl85-66bdl-660r) | 660 W | Very close match | | [S-Energy SL85-66BDL-665R](https://comparepv.com/panel/s-energy-sl85-66bdl-665r) | 665 W | +10 W, +0.3 pp | | [AIKO AIKO-A805-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a805-grh78dw) | 805 W | +150 W, cooler, +4.0 pp | | [AIKO AIKO-A800-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a800-grh78dw) | 800 W | +145 W, cooler, +3.8 pp | | [AIKO AIKO-A795-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a795-grh78dw) | 795 W | +140 W, cooler, +3.7 pp | | [AIKO AIKO-A790-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a790-grh78dw) | 790 W | +135 W, cooler, +3.5 pp | | [Trina Solar TSM-NEG21C.20Q-760](https://comparepv.com/panel/trina-solar-tsm-neg21c-20q-760) | 760 W | +105 W, cooler, +3.4 pp | --- Source: https://comparepv.com/panel/s-energy-sl85-66bdl-655r 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.