--- title: "Runtech China RT400WM 400W Solar Panel - Specs & Review | ComparePV" description: "Runtech China RT400WM 400W solar panel. Specs: 20.50% efficiency, Monocrystalline cells, dimensions, warranty and temperature coefficient." source: "https://comparepv.com/panel/runtech-china-rt400wm" updated: 2026-09-11 --- # Runtech China RT400WM Middle of its segment, weak in heat 6,519 panels in the 300-500 W band, all technologies ## Identity - **Manufacturer:** Runtech China - **Model:** RT400WM - **Series:** RT390~420WM - **Rated power:** 400 W - **Cell technology:** Monocrystalline ## How it compares Compared against 300-500 W band, all technologies (6519 panels). | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Power (Wp) | 400 W | 435 W | Weak - bottom 24% | | | Module efficiency | 20.50% | 21.30% | Typical | 11,308 | | Power density | 204.8 | 212.6 | Typical | 11,370 | | Temperature coefficient | -0.350 | -0.300 | Weak - bottom 23% | 10,419 | | Weight (kg) | 20.5 kg | 22.5 kg | Typical | | | Performance warranty | - | 30 yrs | | | ### Full peer table | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Module efficiency | 20.50% | 21.30% | Typical | 11,308 | | Power density | 204.8 | 212.6 | Typical | 11,370 | | Temperature coefficient | -0.350 | -0.300 | Weak - bottom 23% | 10,419 | | Weight per kWp | 51.2 | 53.2 | Typical | 4,641 | | Performance warranty | - | 30 yrs | | | ### Watch out for - **-0.350 %/°C temperature coefficient** - Bottom 23% of the 300-500 W band, against a median of -0.300. - **Best for:** Residential, shaded-installations and hot-climate. - **Not ideal for:** Hot climates. ## Specification ### Electrical - **Rated power (Pmax):** 400 W - **Efficiency:** 20.50 % - **Voltage at Pmax (Vmp):** 31.01 V - **Current at Pmax (Imp):** 12.90 A - **Open-circuit voltage (Voc):** 37.07 V - **Short-circuit current (Isc):** 13.79 A - **Max system voltage:** 1500 V ### Temperature - **Temperature coefficient of Pmax:** -0.350 %/degC - **Temperature coefficient of Voc:** -0.275 %/degC - **Temperature coefficient of Isc:** 0.045 %/degC - **NOCT:** 45 degC ### Cell and construction - **Cell type:** Monocrystalline - **Cell count:** 108 ### Physical - **Length:** 1722 mm - **Width:** 1134 mm - **Thickness:** 30 mm - **Weight:** 20.5 kg - **Area:** 1.95 m2 - **Power density:** 204.8 Wp/m2 ### Warranty and degradation ## Rank in the whole catalogue | Measure | Position | | --- | --- | | Efficiency | 11308 of 14005 | | Power density | 11370 of 14005 | | Temperature coefficient | 10419 of 14005 | | Weight | 4641 of 14005 | | Warranty | 13880 of 14005 | ## About this series Runtech RT390-420WM series photovoltaic panels are a precise response to the needs of modern prosumer installations, where an optimal price-to-actual energy performance ratio is key. The use of advanced **Half-Cut cell technology** allows for a significant reduction in power losses resulting from internal resistance and ensures more stable module operation in conditions of partial roof shading. Thanks to the use of **innovative Multi-Busbar (MBB) technology**, current flow paths are shorter and more densely distributed, which effectively minimizes the risk of micro-cracks and increases the overall mechanical durability of the cells. This series stands out for its low temperature coefficient, which directly translates into higher yields on hot summer days when standard modules lose efficiency. These products are primarily dedicated to owners of single-family homes and farms seeking **high resistance to potential-induced degradation (PID)** and long-term reliability in the variable Polish climate. Compared to the competition, Runtech modules offer an **optimized frame and tempered glass construction**, which guarantees safety under heavy snow loads. Choosing this series is an investment in energy stability, combining modern aesthetics with solid materials engineering, representing a substantive alternative to more expensive premium segment solutions. ## Notable figures - Efficiency of 20.5% is 1.3pp below the \*\*database\*\* median (21.8%) - Power density of 204.8 W/m² is 13.3 W/m² below \*\*database\*\* median (218.1 W/m²) - needs more roof space - At -0.35%/°C, loses 0.05pp more power per degree than \*\*database\*\* median (-0.30%/°C) - At 20.5 kg, this panel is 6.0 kg lighter than \*\*database\*\* median (26.5 kg) - easier handling during installation - #11308 for efficiency, #10419 for temperature performance out of 14005 panels ## Questions ### Are Runtech RT390-420WM panels suitable for a typical pitched roof? Yes, the RT390-420WM series is designed for residential prosumer installations on pitched roofs. The modules measure 2384×1303×35 mm and weigh approximately 38.7 kg, which is compatible with standard roofing structures. The optimized aluminum frame and 3.2 mm tempered glass provide strong resistance to heavy snow loads typical of Central European winters. ### What is the warranty on Runtech RT390-420WM solar panels? The RT390-420WM series comes with a standard 10-year product and workmanship warranty and a 25-year linear power output guarantee. After 25 years of operation, the panel is rated to retain at least 80.7% of its nominal power output. Exact terms should be confirmed with your local distributor as agreements may vary by market. ### What are the advantages of half-cut cells and Multi-Busbar (MBB) technology in the Runtech RT390-420WM? Half-cut cell technology splits each cell in half, reducing internal resistance and lowering resistive power losses by 2-3% compared to standard full cells. Multi-Busbar shortens current pathways across the cell surface, minimizing the risk of micro-cracks and improving overall mechanical durability. The result is a module efficiency of up to 21.6% and a longer effective service life. ### How do Runtech RT390-420WM panels handle partial shading from a chimney or nearby trees? Thanks to the half-cut cell design, each RT390-420WM module is electrically divided into two independent halves. Shading on the lower section does not block output from the upper section and vice versa. Combined with strong PID resistance built into the cell architecture, this makes the series a reliable choice for rooftops with chimneys, dormers, or adjacent vegetation. ### Do the RT390-420WM panels perform well in winter and at low temperatures? Yes. The low temperature coefficient of the RT390-420WM series means that on cold, sunny winter days the modules can temporarily exceed their STC-rated output. The reinforced frame and 3.2 mm tempered glass also provide high snow-load resistance. This is a key advantage in Poland's climate, where standard panels lose significant output during summer heat peaks. ### What does the RT390~420WM power range mean and which wattage bin should I choose for a home system? The RT390~420WM designation covers power classes from 390 Wp to 420 Wp. Each panel is individually flash-tested under STC conditions and sorted into the corresponding wattage bin. For a typical 5-10 kWp residential installation, selecting the highest available bins (410-420 Wp) maximizes annual energy yield without requiring additional roof space or extra modules. ## Datasheet [Manufacturer datasheet (PDF)](https://comparepv.com/datasheets/RT410MS-bddec3d8715b.pdf) ## Alternatives | Panel | Power | How it differs | | --- | --- | --- | | [Luxor Solar LX-440M/182-108+GG](https://comparepv.com/panel/luxor-solar-lx-440m-182-108-gg) | 440 W | +40 W, cooler, +2.6 pp | | [Just Solar JST-EDMH-(445-465)W-TD (450W class)](https://comparepv.com/panel/just-solar-jst-edmh-445-465-w-td-450w-class) | 450 W | +50 W, cooler, +2.6 pp | | [Q-SUN Solar QNN182-HG450-54](https://comparepv.com/panel/qn-solar-pv-limited-qnn182-hg450-54) | 450 W | +50 W, cooler, +2.5 pp | | [Huayao HY440-N108BDD](https://comparepv.com/panel/huayao-hy440-n108bdd) | 450 W | +50 W, cooler, +2.5 pp | | [BYD NLBK-27-450](https://comparepv.com/panel/byd-nlbk-27-450) | 450 W | +50 W, cooler, +2.5 pp | | [Renesola RS41-450NBG-E3](https://comparepv.com/panel/renesola-rs41-450nbg-e3) | 450 W | +50 W, cooler, +2.5 pp | | [Runtech China RT390WM](https://comparepv.com/panel/runtech-china-rt390wm) | 390 W | -10 W, -0.5 pp | | [Runtech China RT395WM](https://comparepv.com/panel/runtech-china-rt395wm) | 395 W | -0.3 pp | | [Runtech China RT405WM](https://comparepv.com/panel/runtech-china-rt405wm) | 405 W | +0.3 pp | | [Runtech China RT410WM](https://comparepv.com/panel/runtech-china-rt410wm) | 410 W | +10 W, +0.5 pp | | [Runtech China RT415WM](https://comparepv.com/panel/runtech-china-rt415wm) | 415 W | +15 W, +0.8 pp | | [Runtech China RT420WM](https://comparepv.com/panel/runtech-china-rt420wm) | 420 W | +20 W, +1.1 pp | | [Longi Solar LR7-54HJD-510M](https://comparepv.com/panel/longi-lr7-54hjd-510m) | 510 W | +110 W, cooler, +4.5 pp | | [AIKO AIKO-A495-MCE54Mw](https://comparepv.com/panel/aiko-aiko-a495-mce54mw) | 495 W | +95 W, cooler, +4.3 pp | | [Longi Solar LR7-54HJD-505M](https://comparepv.com/panel/longi-lr7-54hjd-505m) | 505 W | +105 W, cooler, +4.2 pp | | [AIKO AIKO-A490-MCE54Mw](https://comparepv.com/panel/aiko-aiko-a490-mce54mw) | 490 W | +90 W, cooler, +4.0 pp | --- Source: https://comparepv.com/panel/runtech-china-rt400wm Not in this file, on the page: a thirty-year output simulator and alternatives filtered by how closely they match these dimensions.