--- title: "DMEGC DM705G12T-B66HSW 705W Solar Panel - Specs & Review | ComparePV" description: "DMEGC DM705G12T-B66HSW 705W solar panel. Specs: 22.70% efficiency, Monocrystalline cells, dimensions, warranty and temperature coefficient." source: "https://comparepv.com/panel/dmegc-hengdian-group-dm705g12t-b66hsw" updated: 2026-09-11 --- # DMEGC DM705G12T-B66HSW Middle of its segment, needs the roof space 420 panels in the segment TOPCon 700-750 W ## Identity - **Manufacturer:** DMEGC - **Model:** DM705G12T-B66HSW - **Series:** DMxxxG12T-B66HSW - **Rated power:** 705 W - **Cell technology:** TOPCon - **Bifacial:** yes ## How it compares Compared against segment TOPCon 700-750 W (420 panels). | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Power (Wp) | 705 W | 715 W | Weak - bottom 22% | | | Module efficiency | 22.70% | 23.00% | Weak - bottom 23% | 3,307 | | Power density | 227.0 | 230.2 | Weak - bottom 21% | 3,361 | | Temperature coefficient | -0.290 | -0.290 | Typical | 2,165 | | Weight (kg) | 37.7 kg | 38.0 kg | Typical | | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | ### Full peer table | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Module efficiency | 22.70% | 23.00% | Weak - bottom 23% | 3,307 | | Power density | 227.0 | 230.2 | Weak - bottom 21% | 3,361 | | Temperature coefficient | -0.290 | -0.290 | Typical | 2,165 | | Weight per kWp | 53.5 | 52.9 | Typical | 7,434 | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | ### Watch out for - **227.0 watts per square metre** - Bottom 21% of the TOPCon 700-750 W segment, against a median of 230.2. - **22.70% module efficiency** - Bottom 23% of the TOPCon 700-750 W segment, against a median of 23.00%. - **Best for:** Commercial, utility-scale and agrivoltaic. - **Not ideal for:** Roofs where every square metre has to count and tight roof space. ## Specification ### Electrical - **Rated power (Pmax):** 705 W - **Efficiency:** 22.70 % - **Voltage at Pmax (Vmp):** 40.58 V - **Current at Pmax (Imp):** 17.40 A - **Open-circuit voltage (Voc):** 48.62 V - **Short-circuit current (Isc):** 18.48 A - **Max system voltage:** 1500 V ### Temperature - **Temperature coefficient of Pmax:** -0.290 %/degC - **Temperature coefficient of Voc:** -0.250 %/degC - **Temperature coefficient of Isc:** 0.048 %/degC - **NOCT:** 42 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:** 37.7 kg - **Area:** 3.11 m2 - **Power density:** 227.0 Wp/m2 ### Warranty and degradation - **Product warranty:** 15 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:** 616 W ## Rank in the whole catalogue | Measure | Position | | --- | --- | | Efficiency | 3307 of 14005 | | Power density | 3361 of 14005 | | Temperature coefficient | 2165 of 14005 | | Weight | 7434 of 14005 | | Warranty | 21 of 14005 | ## Pros - **Highest Efficiency in the Competitive Set** - Maximum module efficiency reaches 23.2%, surpassing all three listed competitors: Gamko New Energy GKA210N132 (23.18%), Renesola RS9-700~720NBG-E1 (23.18%), and Mysolar USA GOLD HJT (23.17%). The higher power density translates into a smaller footprint required to achieve the same energy yield in space-constrained installations. - **Low Temperature Coefficient of -0.29%/°C** - A power temperature coefficient of -0.29%/°C is more favorable than the PERC baseline (-0.35%/°C) and sits at the top end of the range for TOPCon technology. This results in measurably higher energy production during hot summer months — a key advantage for installations in high-temperature operating environments (>50°C NOCT). - **30-Year Linear Warranty, Degradation ≤0.42%/year** - The manufacturer guarantees at least 87.4% of nominal power output after 30 years, with annual degradation not exceeding 0.42%. This is among the longest power warranties available in the segment and a compelling argument in LCOE analyses for commercial and utility-scale ground-mount projects. - **BNEF Tier 1 – Bankable (Q3 2025)** - DMEGC Solar retained its Tier 1 status in the BloombergNEF ranking as of Q3 2025, despite tightened criteria (the reference project threshold was raised from 5 MW to 10 MW). Bankable status streamlines project financing with non-recourse debt — a critical consideration for PV developers seeking project finance from lending institutions. - **Glass-Glass Construction with ~80% Bifaciality** - Dual tempered glass (2 mm) improves resistance to mechanical loads and PID/UV-induced degradation compared to glass-backsheet variants, while a bifaciality factor of approximately 80% enables a realistic 5–25% gain in additional energy yield from reflected irradiance — particularly valuable in installations over high-albedo surfaces and agrivoltaic projects. ## Cons - **32.3 kg Weight — Constraint for Low-Load Rooftops** - The glass-glass construction results in a module weight of 32.3 kg, approximately 12 kg/m² more than typical glass-backsheet modules (~26–28 kg). This may require structural reinforcement or a certified engineering assessment for older buildings, increasing both cost and project lead time in the residential and BIPV/MIPV segments. ## About this series The DMEGC DMxXXG12T-B66HSW series is designed for maximum yield in installations where every meter of structure counts, along with stable performance in varying conditions. The application of **N-type cells in TOPCon technology** helps minimize typical power losses during operation and maintain high productivity, especially at demanding temperatures and intense sunlight. The **double-sided (bifacial) structure** allows capturing reflected light energy too - a real benefit on bright roofs, gravel surfaces, and agrivoltaic farms. The **glass-glass variant** enhances resistance to environmental factors, translating to a lower risk of micro-cracks and material degradation. The DMEGC DMxXXG12T-B66HSW series is an excellent choice for investors seeking **high power density** and predictable parameters in commercial, industrial, agrivoltaic, and large-scale installations. It stands out from many competitors through the combination of advanced cell architecture with a focus on durability and long-term yield. ## Notable figures - Efficiency of 22.7% matches the \*\*TOPCon 700-750W\*\* median - 226.9 W/m² power density is 3.2 W/m² below \*\*TOPCon 700-750W\*\* median (230.2 W/m²) - requires larger installation area - Temperature coefficient of -0.29%/°C matches the \*\*TOPCon 700-750W\*\* median - Bifaciality factor of 80% can add 4-12% extra yield with reflective mounting surface - In the top 24% for efficiency among all TOPCon panels ## Questions ### What warranty does the DMEGC DMxxxG12T-B66HSW series carry, and what does it specifically cover? The DMxxxG12T-B66HSW series comes with a 15-year product warranty covering manufacturing defects and material failures, as well as a 30-year linear power output warranty. The linear power warranty means the manufacturer guarantees that the modules will maintain a defined performance level for three full decades — one of the longest performance warranty standards in the photovoltaic industry. DMEGC is a Tier 1 manufacturer, which simplifies warranty claim enforcement through authorized distributors. ### What is TOPCon technology, and does it genuinely outperform older PERC cells? TOPCon (Tunnel Oxide Passivated Contact) is an N-type cell technology that minimizes carrier recombination at the cell surface. In practice, this translates to higher efficiency — the DMxxxG12T-B66HSW achieves up to 23.2% — and a lower annual degradation rate compared to PERC cells. N-type TOPCon modules also perform better under high-temperature conditions and diffuse irradiance, which is particularly relevant in climates with a high proportion of overcast days. ### Are the DMEGC DMxxxG12T-B66HSW panels suitable for industrial installations and ground-mounted solar farms, or only for rooftop systems? The DMxxxG12T-B66HSW series is designed primarily for commercial, industrial, and utility-scale ground-mounted applications. The bifacial double-glass construction, with a bifaciality factor of approximately 80%, is especially advantageous in systems with high-albedo ground surfaces such as gravel, concrete, or grass, and in agrivoltaic systems where ground-reflected irradiance reaches the rear side of the module, increasing overall energy yield. ### Why does the DMxxxG12T-B66HSW series use glass on both sides instead of a standard backsheet? The glass-glass construction provides superior mechanical resistance and better protects the cells against moisture ingress, micro-damage, and UV degradation compared to a conventional polymer backsheet. This results in slower long-term degradation and a reduced risk of cell micro-cracking over the module's service life. Combined with bifacial light capture, the glass-glass configuration is the recommended standard for installations where modules are exposed to harsh environmental conditions over many years. ### What is the maximum power output of the DMEGC DMxxxG12T-B66HSW module, and how should the right wattage variant be selected for a given project? The highest wattage variant in this series is 720 Wp. Selecting the appropriate variant depends on the available roof or ground area, the maximum voltage and current ratings of the inverter, and the target annual energy yield. For commercial installations above 100 kWp, using the highest available wattage variants is recommended, as this reduces the total module count, cabling runs, and installation labor cost per unit of installed power. ### Is DMEGC a reliable solar panel manufacturer, and is after-sales service readily available? DMEGC (Dongfang Electric Magnetic Co.) is classified as a Tier 1 manufacturer by BloombergNEF, meaning it meets the stringent financial and production capacity criteria used by banks and project finance institutions when evaluating renewable energy projects. The brand's modules are distributed through authorized commercial partners, ensuring access to technical documentation, post-sales support, and warranty enforcement without requiring direct contact with the manufacturer in China. ## Datasheet [Manufacturer datasheet (PDF)](https://comparepv.com/datasheets/66b9d6428009e-ef9e575bd8d4.pdf) ## Alternatives | Panel | Power | How it differs | | --- | --- | --- | | [AIKO AIKO-A680-MDE72Mw](https://comparepv.com/panel/aiko-aiko-a680-mde72mw) | 680 W | Cooler, lighter, +2.5 pp | | [AIKO AIKO-A675-MDE72Mw](https://comparepv.com/panel/aiko-aiko-a675-mde72mw) | 675 W | -30 W, lighter, +2.3 pp | | [AIKO AIKO-A700-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a700-mae78dw) | 700 W | Cooler, lighter, +2.3 pp | | [AIKO AIKO-A695-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a695-mae78dw) | 695 W | Cooler, lighter, +2.2 pp | | [AIKO AIKO-G670-MCH72Mw](https://comparepv.com/panel/aiko-aiko-g670-mch72mw) | 670 W | -35 W, lighter, +2.1 pp | | [Longi Solar LR7-72HVHF-670M](https://comparepv.com/panel/longi-lr7-72hvhf-670m) | 670 W | -35 W, lighter, +2.1 pp | | [Jinko Solar JKM650-670N-66QL6-BDV (670W class)](https://comparepv.com/panel/jinko-solar-jkm650-670n-66ql6-bdv-670w-class) | 670 W | -35 W, lighter, +2.1 pp | | [DMEGC DM695G12T-B66HSW](https://comparepv.com/panel/dmegc-hengdian-group-dm695g12t-b66hsw) | 695 W | -10 W, -0.3 pp | | [DMEGC DM700G12T-B66HSW](https://comparepv.com/panel/dmegc-hengdian-group-dm700g12t-b66hsw) | 700 W | Very close match | | [DMEGC DM710G12T-B66HSW](https://comparepv.com/panel/dmegc-hengdian-group-dm710g12t-b66hsw) | 710 W | Very close match | | [DMEGC DM715G12T-B66HSW](https://comparepv.com/panel/dmegc-hengdian-group-dm715g12t-b66hsw) | 715 W | +10 W, +0.3 pp | | [DMEGC DM720G12T-B66HSW](https://comparepv.com/panel/dmegc-hengdian-group-dm720g12t-b66hsw) | 720 W | +15 W, +0.5 pp | | [AIKO AIKO-A805-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a805-grh78dw) | 805 W | +100 W, cooler, +2.4 pp | | [AIKO AIKO-A800-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a800-grh78dw) | 800 W | +95 W, cooler, +2.2 pp | | [AIKO AIKO-A795-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a795-grh78dw) | 795 W | +90 W, cooler, +2.1 pp | | [AIKO AIKO-A790-GRH78Dw](https://comparepv.com/panel/aiko-aiko-a790-grh78dw) | 790 W | +85 W, cooler, +1.9 pp | --- Source: https://comparepv.com/panel/dmegc-hengdian-group-dm705g12t-b66hsw 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.