--- title: "Longi Solar RL550HM 550W Solar Panel - Specs & Review | ComparePV" description: "Longi Solar RL550HM 550W solar panel. Specs: 21.50% efficiency, Monocrystalline cells, dimensions, warranty and temperature coefficient." source: "https://comparepv.com/panel/longi-solar-rl550hm" updated: 2026-09-11 --- # Longi Solar RL550HM Light for its output, weak in heat 589 panels in the segment PERC 550-600 W ## Identity - **Manufacturer:** Longi Solar - **Model:** RL550HM - **Series:** Monocrystalline 144 - **Rated power:** 550 W - **Cell technology:** PERC ## How it compares Compared against segment PERC 550-600 W (589 panels). | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Power (Wp) | 550 W | 560 W | Weak - bottom 15% | | | Module efficiency | 21.50% | 21.29% | Strong - top 18% | 7,958 | | Power density | 212.8 | 212.9 | Typical | 8,643 | | Temperature coefficient | -0.470 | -0.350 | Weak - bottom 1% | 13,879 | | Weight (kg) | 27.0 kg | 30.8 kg | Strong - top 13% | | | Performance warranty | 25 yrs | 27 yrs | Weak - bottom 24% | 9,798 | ### Full peer table | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Module efficiency | 21.50% | 21.29% | Strong - top 18% | 7,958 | | Power density | 212.8 | 212.9 | Typical | 8,643 | | Temperature coefficient | -0.470 | -0.350 | Weak - bottom 1% | 13,879 | | Weight per kWp | 49.1 | 52.7 | Strong - top 13% | 2,721 | | Performance warranty | 25 yrs | 27 yrs | Weak - bottom 24% | 9,798 | ### Strengths - **49.1 kg per kWp** - Top 13% of the PERC 550-600 W segment, against a median of 52.7. - **21.50% module efficiency** - Top 18% of the PERC 550-600 W segment, against a median of 21.29%. ### Watch out for - **-0.470 %/°C temperature coefficient** - Bottom 1% of the PERC 550-600 W segment, against a median of -0.350. Ranked 13,879th in the whole database. - **25 year performance warranty** - Bottom 24% of the PERC 550-600 W segment, against a median of 27 yrs. - **Best for:** Residential, commercial and shaded-installations. - **Not ideal for:** Hot climates and owners who want a long output guarantee. ## Specification ### Electrical - **Rated power (Pmax):** 550 W - **Efficiency:** 21.50 % - **Voltage at Pmax (Vmp):** 41.95 V - **Current at Pmax (Imp):** 13.12 A - **Open-circuit voltage (Voc):** 49.80 V - **Short-circuit current (Isc):** 13.98 A - **Max system voltage:** 1500 V ### Temperature - **Temperature coefficient of Pmax:** -0.470 %/degC - **Temperature coefficient of Voc:** -0.346 %/degC - **Temperature coefficient of Isc:** 0.036 %/degC - **NOCT:** 47 degC ### Cell and construction - **Cell type:** Monocrystalline - **Cell technology:** PERC - **Cell count:** 144 ### Physical - **Length:** 2279 mm - **Width:** 1134 mm - **Thickness:** 35 mm - **Weight:** 27.0 kg - **Area:** 2.58 m2 - **Power density:** 212.8 Wp/m2 ### Warranty and degradation - **Product warranty:** 10 years - **Performance warranty:** 25 years ## Rank in the whole catalogue | Measure | Position | | --- | --- | | Efficiency | 7958 of 14005 | | Power density | 8643 of 14005 | | Temperature coefficient | 13879 of 14005 | | Weight | 2721 of 14005 | | Warranty | 9798 of 14005 | ## Pros - **High efficiency up to 21.5%** - The 20.7-21.5% efficiency range places this series above comparable 144 half-cut modules in the 530-550 Wp class, such as IBC Solar 182M (21.28%), Goldi Solar GS10-B144-TF (21.3%), and Jetion JT SGh (21.3%). - **Gallium doping reduces LID** - Longi's gallium-doped silicon technology, developed with Shin-Etsu, cuts light-induced degradation from a typical ~0.6%/year for PERC down to around 0.45%/year, resulting in roughly 11-12% total power loss over 25 years versus higher rates typical of older P-type modules. - **144 half-cut cells improve shading tolerance** - The half-cut architecture with 144 half-cells lowers resistive losses and improves module behavior under partial shading (e.g., from a chimney or tree), which matters for rooftop installations with uneven sun exposure. - **Tier-1 manufacturer, project bankability** - LONGi Solar has consistently held BloombergNEF Tier 1 status (confirmed in Q1 and Q2 2026), which supports non-recourse bank financing for commercial and utility-scale PV projects. The company has been operating since 2000. - **Smart soldering limits microcracks** - The applied soldering process supports even current flow between cells and increases module resistance to microcracks arising during transport and installation, meaningfully lowering the risk of premature power degradation. ## Cons - **Discontinued since 2023** - Launched in 2019, this series was phased out of production in 2023 - availability of new units, service support, and spare parts is limited, as LONGi has shifted focus to newer product lines (including the Hi-MO series with HPBC technology). - **PERC technology superseded by newer options** - PERC was the standard when this series launched, but current market leaders - including LONGi itself with HPBC cells reaching 28.13% efficiency - now offer higher efficiency and often longer power warranties than the standard 25 years featured in this series, worth weighing against current tier-1 offerings. ## About this series The Longi Solar Monocrystalline 144 series consists of 144-cell modules designed to minimize energy losses and operate more stably under partial shading. The use of half-cut technology in combination with PERC monocrystalline cells improves the module's performance in real-world conditions - when shadows from chimneys, trees, or dirt only cover a portion of the surface. Another noteworthy feature is the **intelligent soldering**, which supports even current flow and increases resistance to micro-cracks during transport and installation. In practice, this series addresses common issues with rooftop and commercial installations - fluctuations in power output in low light, power drops due to uneven sun exposure, and compatibility requirements with modern inverters. These modules also feature **gallium-doped technology**, which limits LID degradation, resulting in more predictable performance over a longer period. This makes them a good choice for prosumers, businesses, and farms that want **higher yields in challenging conditions** and **guaranteed performance for years to come**. ## Notable figures - At 21.5% efficiency, this panel is on par with typical \*\*PERC 550-600W\*\* modules - Power density of 212.8 W/m² matches the \*\*PERC 550-600W\*\* median - At -0.47%/°C, loses 0.12pp more power per degree than \*\*PERC 550-600W\*\* median (-0.35%/°C) - 27.0 kg weight - 3.8 kg lighter than \*\*PERC 550-600W\*\* median (30.8 kg), reducing installation effort - Ranked #7958 out of 14005 panels for efficiency in the database ## Questions ### Is the Longi Solar Monocrystalline 144 series still available for purchase? The Longi Solar Monocrystalline 144 series has been discontinued and is no longer actively manufactured by LONGi Solar. Limited stock may still be available from select distributors, but new supply should not be expected. If you require full availability and ongoing service support, consider LONGi's current lineup, such as the Hi-MO 6 or Hi-MO X10 series. ### What warranty comes with Longi Solar Monocrystalline 144 panels? Longi Solar Monocrystalline 144 modules include a 10-year product warranty covering material and workmanship defects, plus a 25-year linear power output warranty guaranteeing that a specified percentage of rated power is maintained over a quarter century. These are standard Tier 1 manufacturer warranty terms and provide solid long-term assurance for both residential prosumers and commercial PV farms. ### Does the 144 half-cut cell layout actually help with partial roof shading? Yes. In the 144 half-cut cell configuration, each cell is split in half, reducing internal resistance and limiting losses caused by shading from chimneys, antennas, or tree branches. The electrical segmentation of the module into independent sections means that a shaded area suppresses output from the rest of the panel to a significantly lesser degree. This is a particularly valuable feature on pitched roofs with dormers or other shading obstacles. ### What is gallium doping and does it actually reduce module degradation? Light-induced degradation (LID) is a phenomenon in which standard boron-based monocrystalline modules lose a few percent of rated power during the first weeks of operation. The Longi Solar Monocrystalline 144 series uses gallium-doped PERC cells, which significantly limits this effect. The result is more stable and predictable energy production throughout the system's entire service life, translating into better real-world yield over a long-term horizon. ### What is the maximum power of Longi Solar Monocrystalline 144 panels and how does it affect system sizing? The maximum power output of modules in this series reaches 550 Wp. At typical irradiation levels in Central Europe of approximately 1,000–1,100 kWh/kWp per year, a single panel can generate around 550–605 kWh annually. The high unit power rating allows a larger total system capacity to be installed on the same roof area, which is critical when mounting space is limited. ### Are the 550 Wp Longi Solar Monocrystalline 144 panels compatible with popular inverters? The 550 Wp modules in the Monocrystalline 144 series have electrical parameters compatible with most inverters featuring MPPT inputs rated for 1000 V or 1500 V system voltage. Before selecting an inverter, verify the specific module datasheet and confirm that the inverter's input voltage and current range match the panel's parameters. LONGi monocrystalline modules are widely used with inverters from Fronius, SMA, Huawei, and SolarEdge. ## Datasheet [Manufacturer datasheet (PDF)](https://comparepv.com/datasheets/RL550HM-d9b7f6155e1d.pdf) ## Alternatives | Panel | Power | How it differs | | --- | --- | --- | | [Longi Solar LR7-54HJD-510M](https://comparepv.com/panel/longi-lr7-54hjd-510m) | 510 W | Cooler, +3.5 pp, +5 yr warranty | | [Longi Solar LR7-60HVH-560M](https://comparepv.com/panel/longi-lr7-60hvh-560m) | 560 W | Cooler, +3.3 pp, +5 yr warranty | | [Longi Solar LR7-54HJD-505M](https://comparepv.com/panel/longi-lr7-54hjd-505m) | 505 W | Cooler, +3.2 pp, +5 yr warranty | | [Longi Solar LR7-60HVH-555M](https://comparepv.com/panel/longi-lr7-60hvh-555m) | 555 W | Cooler, +3.1 pp, +5 yr warranty | | [Longi Solar LR7-54HJD-500M](https://comparepv.com/panel/longi-lr7-54hjd-500m) | 500 W | -50 W, cooler, +3.0 pp | | [Longi Solar RL530HM](https://comparepv.com/panel/longi-solar-rl530hm) | 530 W | -20 W, -0.8 pp | | [Longi Solar RL535HM](https://comparepv.com/panel/longi-solar-rl535hm) | 535 W | -15 W, -0.6 pp | | [Longi Solar LR5-72HBD-540M](https://comparepv.com/panel/longi-lr5-72hbd-540m) | 540 W | Cooler, heavier, +5 yr warranty | | [Longi Solar RL540HM](https://comparepv.com/panel/longi-solar-rl540hm) | 540 W | -10 W, -0.4 pp | | [Longi Solar LR5-72HPH-545M](https://comparepv.com/panel/longi-lr5-72hph-545m) | 545 W | Cooler, -0.4 pp | | [Longi Solar RL545HM](https://comparepv.com/panel/longi-solar-rl545hm) | 545 W | Very close match | | [Longi Solar LR5-72HBD-550M](https://comparepv.com/panel/longi-lr5-72hbd-550m) | 550 W | Cooler, heavier, +5 yr warranty | | [AIKO AIKO-A650-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a650-mae72mw) | 650 W | +100 W, cooler, +3.7 pp | | [AIKO AIKO-A645-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a645-mae72mw) | 645 W | +95 W, cooler, +3.5 pp | | [AIKO AIKO-A640-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a640-mae72mw) | 640 W | +90 W, cooler, +3.3 pp | | [AIKO AIKO-A635-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a635-mae72mw) | 635 W | +85 W, cooler, +3.1 pp | --- Source: https://comparepv.com/panel/longi-solar-rl550hm Not in this file, on the page: a thirty-year output simulator and alternatives filtered by how closely they match these dimensions.