--- title: "Longi Solar LR5-66HPH-500M 500W Solar Panel - Specs & Review | ComparePV" description: "Longi Solar LR5-66HPH-500M 500W solar panel. Specs: 21.30% efficiency, Monocrystalline cells, dimensions, warranty and temperature coefficient." source: "https://comparepv.com/panel/longi-lr5-66hph-500m" updated: 2026-09-11 --- # Longi Solar LR5-66HPH-500M Space saver, short guarantee 706 panels in the segment PERC 500-550 W ## Identity - **Manufacturer:** Longi Solar - **Model:** LR5-66HPH-500M - **Series:** Hi-MO 5m - **Rated power:** 500 W - **Cell technology:** PERC ## How it compares Compared against segment PERC 500-550 W (706 panels). | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Power (Wp) | 500 W | 535 W | Weak - bottom 4% | | | Module efficiency | 21.30% | 20.90% | Strong - top 4% | 8,519 | | Power density | 212.9 | 209.0 | Strong - top 3% | 8,599 | | Temperature coefficient | -0.350 | -0.350 | Typical | 10,419 | | Weight (kg) | 25.1 kg | 28.4 kg | Strong - top 18% | | | Performance warranty | 25 yrs | 30 yrs | Weak - bottom 23% | 9,798 | ### Full peer table | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Module efficiency | 21.30% | 20.90% | Strong - top 4% | 8,519 | | Power density | 212.9 | 209.0 | Strong - top 3% | 8,599 | | Temperature coefficient | -0.350 | -0.350 | Typical | 10,419 | | Weight per kWp | 50.2 | 53.0 | Strong - top 18% | 3,664 | | Performance warranty | 25 yrs | 30 yrs | Weak - bottom 23% | 9,798 | ### Strengths - **212.9 watts per square metre** - Top 3% of the PERC 500-550 W segment, against a median of 209.0. Ranked 8,599th in the whole database. - **21.30% module efficiency** - Top 4% of the PERC 500-550 W segment, against a median of 20.90%. Ranked 8,519th in the whole database. - **50.2 kg per kWp** - Top 18% of the PERC 500-550 W segment, against a median of 53.0. ### Watch out for - **25 year performance warranty** - Bottom 23% of the PERC 500-550 W segment, against a median of 30 yrs. - **Best for:** Residential, commercial and shaded-installations. - **Not ideal for:** Owners who want a long output guarantee. ## Specification ### Electrical - **Rated power (Pmax):** 500 W - **Efficiency:** 21.30 % - **Voltage at Pmax (Vmp):** 38.38 V - **Current at Pmax (Imp):** 13.03 A - **Open-circuit voltage (Voc):** 45.55 V - **Short-circuit current (Isc):** 13.90 A - **Max system voltage:** 1500 V ### Temperature - **Temperature coefficient of Pmax:** -0.350 %/degC - **Temperature coefficient of Voc:** -0.270 %/degC - **Temperature coefficient of Isc:** 0.048 %/degC - **NOCT:** 45 degC ### Cell and construction - **Cell type:** Monocrystalline - **Cell technology:** PERC - **Cell count:** 132 ### Physical - **Length:** 2073 mm - **Width:** 1133 mm - **Thickness:** 35 mm - **Weight:** 25.1 kg - **Area:** 2.35 m2 - **Power density:** 212.9 Wp/m2 ### Warranty and degradation - **Product warranty:** 12 years - **Performance warranty:** 25 years - **Output guaranteed at end of warranty:** 84.8 % - **First-year degradation:** 2.00 % - **Annual degradation:** 0.55 % - **Output after 30 years:** 410 W ## Rank in the whole catalogue | Measure | Position | | --- | --- | | Efficiency | 8519 of 14005 | | Power density | 8599 of 14005 | | Temperature coefficient | 10419 of 14005 | | Weight | 3664 of 14005 | | Warranty | 9798 of 14005 | ## Pros - **Tier-1 manufacturer with proven bankability** - LONGi holds BNEF Tier 1 status (Q2 2026) and an AAA rating in PV Tech's bankability ranking for 25 consecutive quarters. This provides real risk mitigation for investors and lenders financing PV projects. - **Gallium doping mitigates LID** - Replacing boron with gallium as the p-type dopant in the PERC cells eliminates the typical 1-2% first-year Light-Induced Degradation (LID) loss seen in conventional boron-doped modules, translating into higher real-world energy yield from day one. - **Half-cut mono PERC cells + Smart Soldering** - Splitting cells into halves reduces resistive losses and improves partial-shading tolerance, while the Smart Soldering precision-bonding process improves interconnect reliability under mechanical and thermal stress. - **~13A operating current matches string inverters** - Optimized electrical parameters simplify pairing with mainstream string inverters without oversizing the array, lowering BoS costs and simplifying the electrical design. ## Cons - **Production discontinued in 2024** - The Hi-MO 5m series has been phased out (produced 2022-2024), meaning limited availability of identical modules for system extensions and potentially longer lead times for warranty claims fulfilled with replacement stock. - **Efficiency trails current segment leaders** - The 21.5% peak efficiency lags newer designs such as Q-SUN Qrystal N10 (22.7%, N-type technology) at the same 505 Wp power class - a roughly 5.6% relative gap, meaning lower yield per m² on space-constrained roofs. - **Monofacial only, no bifacial option** - The absence of a bifacial variant limits additional albedo-driven yield, which matters for ground-mount arrays or reflective C&I roofs where competing series offer double-sided options. - **12-year product warranty below current market trend** - The standard 12-year product warranty is shorter than the 15-25 years now offered by many Tier-1 manufacturers on newer N-type series, which can affect comparability in long-term TCO calculations. ## About this series The Longi Solar Hi-MO 5m series was designed specifically for rooftop installations, where easy mounting, predictable performance, and high yield in real-world conditions are essential. The use of **half-cell monocrystalline PERC solar cells** helps reduce losses and stabilize module performance, especially when part of the area is less well-lit. A key feature is **doping with gallium (anti-LID)**, which reduces the early degradation effect and supports maintaining power over a long period - a concrete benefit for investors focusing on production energy returns, not just initial parameters. The Hi-MO 5m also utilizes **Smart Soldering**, meaning precise cell connections, which improves connection reliability and supports module operation under load. Additionally, **optimized electrical parameters** facilitate compatibility with popular string inverters, reducing the risk of losses and simplifying the design process. This is an excellent choice for residential, small, and medium-sized businesses, as well as C&I rooftops, where competition often requires compromises between dimensions, compatibility, and longevity. ## Notable figures - Efficiency of 21.3% matches the \*\*PERC 500-550W\*\* median - 212.9 W/m² power density - 3.9 W/m² more than \*\*PERC 500-550W\*\* median (209.0 W/m²), more power per roof area - At -0.35%/°C, hot weather performance is typical for \*\*PERC 500-550W\*\* panels - At 25.1 kg, this panel is 3.3 kg lighter than \*\*PERC 500-550W\*\* median (28.4 kg) - easier handling during installation - #8519 for efficiency, #10419 for temperature performance out of 14005 panels ## Questions ### Is the LONGi Solar Hi-MO 5m series still available for purchase? The Hi-MO 5m series has been discontinued and is no longer actively manufactured by LONGi Solar. It may still be found as clearance stock at some distributors, but availability is limited and declining. For new installations, newer LONGi series such as Hi-MO 6 or Hi-MO 7 are recommended, offering higher efficiency and ongoing manufacturer support. ### What warranty does the LONGi Solar Hi-MO 5m panel come with? LONGi Solar provides a 12-year product warranty (covering material and workmanship defects) and a 25-year linear power output warranty for the Hi-MO 5m series. This means the manufacturer guarantees a defined minimum power yield relative to the rated 505 W output over 25 years. The warranty applies when the module is installed per the manufacturer's documentation and free from mechanical damage. ### What is gallium doping (anti-LID) in Hi-MO 5m panels and does it matter in practice? Gallium doping replaces boron as the p-type dopant in PERC cells, significantly reducing Light-Induced Degradation (LID) — the power loss that occurs during the first hours of light exposure. In conventional boron-doped cells, LID can reduce output by 1–2% in the first year. Gallium-doped cells retain power closer to the nameplate rating from day one, which improves energy yield and shortens the effective payback period. ### Do LONGi Hi-MO 5m panels perform well under partial shading conditions? Yes, the half-cut PERC cell design improves shade tolerance meaningfully. By splitting each cell into two smaller halves, shading on one section of the module does not fully interrupt the output of the remaining section. This is especially relevant on rooftops with chimneys, antennas, or dormers. Note that the Hi-MO 5m is a monofacial module — it does not gain from ground-reflected light — but the rear surface is durable and resistant to moisture ingress. ### Are Hi-MO 5m 505 W panels compatible with standard string inverters? Yes, the Hi-MO 5m features optimized electrical parameters — voltage and current characteristics suited to the MPPT input ranges of popular string inverters from brands such as Fronius, SMA, Huawei, and Growatt. Before installation, verify that the open-circuit string voltage (Voc × panel count) stays within the inverter's maximum DC input limit, which is standard practice for any PV system design. ### How does LONGi's Smart Soldering in Hi-MO 5m differ from conventional cell interconnection? Smart Soldering is LONGi's precision interconnection process that reduces mechanical stress at solder joints. Conventional high-temperature soldering can induce microcracks in thin half-cut cells. The lower-stress process reduces microcrack risk, resulting in better long-term module reliability, a lower hot-spot probability, and reduced power loss under sustained mechanical loads such as snow or wind pressure. ## Datasheet [Manufacturer datasheet (PDF)](https://comparepv.com/datasheets/690605aadac63bdc-84774bed6ff8.pdf) ## Alternatives | Panel | Power | How it differs | | --- | --- | --- | | [Longi Solar LR7-54HJD-510M](https://comparepv.com/panel/longi-lr7-54hjd-510m) | 510 W | Cooler, +3.7 pp, +5 yr warranty | | [AIKO AIKO-A495-MCE54Mw](https://comparepv.com/panel/aiko-aiko-a495-mce54mw) | 495 W | Cooler, +3.5 pp, +5 yr warranty | | [Longi Solar LR7-54HJD-505M](https://comparepv.com/panel/longi-lr7-54hjd-505m) | 505 W | Cooler, +3.4 pp, +5 yr warranty | | [AIKO AIKO-A490-MCE54Mw](https://comparepv.com/panel/aiko-aiko-a490-mce54mw) | 490 W | Cooler, +3.2 pp, +5 yr warranty | | [Longi Solar LR7-54HJD-500M](https://comparepv.com/panel/longi-lr7-54hjd-500m) | 500 W | Cooler, +3.2 pp, +5 yr warranty | | [Talesun CIPRO-TN9C54M-500W](https://comparepv.com/panel/talesun-cipro-tn9c54m-500w) | 500 W | Cooler, +3.2 pp, +5 yr warranty | | [Longi Solar LR5-66HPH-480M](https://comparepv.com/panel/longi-lr5-66hph-480m) | 480 W | -20 W, -0.9 pp | | [Longi Solar LR5-66HPH-485M](https://comparepv.com/panel/longi-lr5-66hph-485m) | 485 W | -15 W, -0.7 pp | | [Longi Solar LR5-66HPH-490M](https://comparepv.com/panel/longi-lr5-66hph-490m) | 490 W | -10 W, -0.4 pp | | [Longi Solar LR5-66HPH-495M](https://comparepv.com/panel/longi-lr5-66hph-495m) | 495 W | Very close match | | [Longi Solar LR5-66HPH-505M](https://comparepv.com/panel/longi-lr5-66hph-505m) | 505 W | Very close match | | [Longi Solar LR7-60HVH-560M](https://comparepv.com/panel/longi-lr7-60hvh-560m) | 560 W | +60 W, cooler, +3.5 pp | | [Longi Solar LR7-60HVH-555M](https://comparepv.com/panel/longi-lr7-60hvh-555m) | 555 W | +55 W, cooler, +3.3 pp | | [Longi Solar LR7-60HVHL-550M](https://comparepv.com/panel/longi-lr7-60hvhl-550m) | 550 W | Cooler, lighter, +3.1 pp | | [Jinko Solar JKM545-54QL6-DV-F1-EU](https://comparepv.com/panel/jinko-solar-jkm545-54ql6-dv-f1-eu) | 545 W | Cooler, +3.0 pp, +5 yr warranty | | [Longi Solar LR7-60HVH-545M](https://comparepv.com/panel/longi-lr7-60hvh-545m) | 545 W | Cooler, +2.9 pp, +5 yr warranty | --- Source: https://comparepv.com/panel/longi-lr5-66hph-500m Not in this file, on the page: a thirty-year output simulator and alternatives filtered by how closely they match these dimensions.