--- title: "JA Solar JAM78S30-590/MR 590W Solar Panel - Specs & Review | ComparePV" description: "JA Solar JAM78S30-590/MR 590W solar panel. Specs: 21.10% efficiency, Monocrystalline cells, dimensions, warranty and temperature coefficient." source: "https://comparepv.com/panel/ja-solar-jam78s30-590-mr" updated: 2026-09-11 --- # JA Solar JAM78S30-590/MR Middle of its segment, short guarantee 589 panels in the segment PERC 550-600 W ## Identity - **Manufacturer:** JA Solar - **Model:** JAM78S30-590/MR - **Series:** JAM78S30 580-605/MR - **Rated power:** 590 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) | 590 W | 560 W | Strong - top 17% | | | Module efficiency | 21.10% | 21.29% | Typical | 9,297 | | Power density | 211.1 | 212.9 | Typical | 9,292 | | Temperature coefficient | -0.350 | -0.350 | Typical | 10,419 | | Weight (kg) | 30.5 kg | 30.8 kg | Typical | | | Performance warranty | 25 yrs | 27 yrs | Weak - bottom 24% | 9,798 | ### Full peer table | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Module efficiency | 21.10% | 21.29% | Typical | 9,297 | | Power density | 211.1 | 212.9 | Typical | 9,292 | | Temperature coefficient | -0.350 | -0.350 | Typical | 10,419 | | Weight per kWp | 51.7 | 52.7 | Typical | 5,079 | | Performance warranty | 25 yrs | 27 yrs | Weak - bottom 24% | 9,798 | ### Watch out for - **25 year performance warranty** - Bottom 24% of the PERC 550-600 W segment, against a median of 27 yrs. - **Best for:** Utility-scale, commercial and shaded-installations. - **Not ideal for:** Owners who want a long output guarantee. ## Specification ### Electrical - **Rated power (Pmax):** 590 W - **Efficiency:** 21.10 % - **Voltage at Pmax (Vmp):** 44.80 V - **Current at Pmax (Imp):** 13.17 A - **Open-circuit voltage (Voc):** 53.30 V - **Short-circuit current (Isc):** 13.93 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 technology:** PERC - **Cell count:** 156 ### Physical - **Length:** 2465 mm - **Width:** 1134 mm - **Thickness:** 35 mm - **Weight:** 30.5 kg - **Area:** 2.80 m2 - **Power density:** 211.1 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:** 484 W ## Rank in the whole catalogue | Measure | Position | | --- | --- | | Efficiency | 9297 of 14005 | | Power density | 9292 of 14005 | | Temperature coefficient | 10419 of 14005 | | Weight | 5079 of 14005 | | Warranty | 9798 of 14005 | ## Pros - **Tier-1 bankable manufacturer** - JA Solar appears on the BNEF Tier 1 Q2 2026 list, confirming bankability for project finance. With operations since 2005 and annual shipments exceeding 100 GWp, the company presents minimal counterparty risk for utility-scale PV asset owners. - **High module wattage — BoS cost reduction** - The 580–605 Wp range delivers the required system capacity with fewer modules, fewer string connections, and reduced installation time. For a 1 MWp plant, this series requires approximately 15–17% fewer modules compared to typical 500 Wp modules from 2019–2020, directly reducing BoS and logistics costs. - **25-year linear power warranty (≤0.55%/yr degradation)** - JA Solar guarantees annual degradation not exceeding 0.55% and a minimum of 84.8% of rated power after 25 years, backed by a 12-year product warranty. This is a competitive commitment for PERC-class modules. - **IP68-rated junction box** - The IP68 junction box rating ensures complete dust-tight protection and resistance to sustained water immersion — critical for ground-mount installations exposed to heavy rainfall, flooding, and dust accumulation, reducing the risk of field electrical failures. - **182 mm cells + 11BB + half-cut configuration** - The M10 (182 mm) cell format with 11-busbar and half-cut architecture reduces resistive current losses and improves performance under partial shading. The 6×26 cell layout (156 cells) in a 2465×1134 mm frame sustains module efficiency up to 21.6% within the PERC class. ## Cons - **Discontinued series (2021–2023)** - Per manufacturer data, the JAM78S30/MR series ended production in 2023. New procurement relies on warehouse stock or secondary markets, creating risks around module availability for system expansion and challenges matching electrical parameters during warranty service or repowering. - **P-type PERC — higher LID and annual degradation** - P-type PERC cells are susceptible to Light-Induced Degradation (LID) caused by boron-oxygen defects. Annual degradation reaches 0.55%, while competing N-type TOPCon modules (e.g., GCL SIROT NT10/72GDF or newer JA Solar lines) exhibit 0.30–0.40%/yr. Over a 25-year asset life, this translates to meaningfully lower cumulative energy yield. - **Monofacial — no bifacial energy gain** - The glass-backsheet (monofacial) construction precludes harvesting albedo radiation from the ground. Bifacial alternatives within the same family (JAM78D30 580–605/MB) offer a bifaciality factor of ~70%, delivering a potential energy gain of 5–15% kWh/kWp in ground-mount installations over reflective surfaces. - **Efficiency gap vs. newer competition** - Peer comparable GCL SIROT NT10/72GDF achieves 23.42% module efficiency at the same maximum power of 605 Wp — approximately 1.8 percentage points above the JAM78S30/MR's 21.6%. This gap stems from newer N-type cell technology and translates to higher energy output per unit footprint in real-world installations. ## About this series JA Solar JAM78S30 580-605/MR series modules are designed for installations where high power per unit and reliable operation in long strings are crucial. The use of large monocrystalline cells in **PERC** technology helps better utilize light under real working conditions, while the **monofacial glass-backsheet** construction remains a practical choice where predictable yield and simple integration with standard farm infrastructure are prioritized. A key feature of this series is its approach focused on reducing the entire system's costs - fewer modules to achieve the required power, fewer connections, and faster installation, facilitating budget and schedule control. The modules feature an **IP68 connector box**, supporting reliability in rain, snow, and dusty conditions. This is an excellent choice for PV farms, large industrial rooftops, and commercial projects, where logistics, serviceability, **low degradation over time**, and stable energy yield are important. ## Notable figures - Efficiency of 21.1% matches the \*\*PERC 550-600W\*\* median - Power density of 211.1 W/m² matches the \*\*PERC 550-600W\*\* median - Temperature coefficient of -0.35%/°C matches the \*\*PERC 550-600W\*\* median - #9297 for efficiency, #10419 for temperature performance out of 14005 panels ## Questions ### Is the JA Solar JAM78S30 580-605/MR series still available for purchase? The JAM78S30 580-605/MR series has been discontinued and is no longer part of JA Solar's standard product lineup. Newer JA Solar series with comparable or higher power output are recommended for new installations. Limited stock may still be available through distributors — always verify current availability directly with your supplier. ### What warranties come with the JA Solar JAM78S30 580-605/MR modules? JA Solar provides a 12-year product warranty covering material and workmanship defects, and a 25-year linear power output warranty. After 25 years, modules are guaranteed to retain at least 84.8% of their rated power, corresponding to an annual degradation rate of no more than 0.55%. These are standard warranty terms for Tier 1 modules of this class. ### How does the JAM78S30 605W panel perform in high summer temperatures? The temperature coefficient of Pmax is -0.350%/°C, resulting in moderate power losses at high temperatures — typical for PERC modules of this generation. At a cell temperature of 65°C (a common summer scenario), power loss is approximately 14%. This is an acceptable figure for large industrial rooftop and ground-mounted systems where good module ventilation helps limit thermal buildup. ### What does PERC and half-cut cell technology mean in the JAM78S30 series, and does it matter for my installation? PERC (Passivated Emitter and Rear Cell) adds a reflective passivation layer to the rear of each cell, boosting light absorption and pushing module efficiency up to 21.6% in this series. The half-cut configuration splits each cell in two, reducing resistive losses and improving tolerance to partial shading. In practice, this translates to better energy yield on overcast days and under non-uniform irradiance conditions. ### Are the JAM78S30 580-605/MR panels suitable for a large industrial rooftop? Yes, this series was designed for large commercial and utility-scale installations. Each module measures 2465 x 1134 x 35 mm and weighs approximately 31.1 kg, so a robust racking structure is required. The high unit power output (up to 605 Wp) reduces the number of modules and string connections needed, simplifying installation logistics and lowering BoS costs on large projects. ### Is the IP68-rated junction box on the JAM78S30 sufficient for installations exposed to rain and dust? An IP68-rated junction box provides full protection against dust ingress and continuous water immersion, which in a typical rooftop or ground-mount context means reliable performance through heavy rainfall, pressure washing, and dusty environments. This rating is well suited for industrial facilities, agricultural installations, and projects in demanding climatic conditions. ## Datasheet [Manufacturer datasheet (PDF)](https://comparepv.com/datasheets/JAM78S30-MR-daa814a089cf.pdf) ## Alternatives | Panel | Power | How it differs | | --- | --- | --- | | [Longi Solar LR7-60HVH-560M](https://comparepv.com/panel/longi-lr7-60hvh-560m) | 560 W | Cooler, lighter, +3.7 pp | | [AIKO AIKO-A640-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a640-mae72mw) | 640 W | +50 W, cooler, +3.7 pp | | [Longi Solar LR7-60HVH-555M](https://comparepv.com/panel/longi-lr7-60hvh-555m) | 555 W | Cooler, lighter, +3.5 pp | | [AIKO AIKO-A635-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a635-mae72mw) | 635 W | Cooler, +3.5 pp, +5 yr warranty | | [AIKO AIKO-A630-MAH72Dw](https://comparepv.com/panel/aiko-aiko-a630-mah72dw) | 630 W | Cooler, +3.3 pp, +5 yr warranty | | [Longi Solar LR7-60HVHL-550M](https://comparepv.com/panel/longi-lr7-60hvhl-550m) | 550 W | Cooler, lighter, +3.3 pp | | [JA Solar JAM78S30-580/MR](https://comparepv.com/panel/ja-solar-jam78s30-580-mr) | 580 W | -10 W, -0.4 pp | | [JA Solar JAM78S30-585/MR](https://comparepv.com/panel/ja-solar-jam78s30-585-mr) | 585 W | -0.2 pp | | [JA Solar JAM78S30-595/MR](https://comparepv.com/panel/ja-solar-jam78s30-595-mr) | 595 W | Very close match | | [JA Solar JAM78S30-600/MR](https://comparepv.com/panel/ja-solar-jam78s30-600-mr) | 600 W | +10 W, +0.4 pp | | [AIKO AIKO-A680-MDE72Mw](https://comparepv.com/panel/aiko-aiko-a680-mde72mw) | 680 W | +90 W, cooler, +4.1 pp | | [AIKO AIKO-A675-MDE72Mw](https://comparepv.com/panel/aiko-aiko-a675-mde72mw) | 675 W | +85 W, cooler, +3.9 pp | | [AIKO AIKO-A700-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a700-mae78dw) | 700 W | +110 W, cooler, +3.9 pp | | [AIKO AIKO-A695-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a695-mae78dw) | 695 W | +105 W, cooler, +3.8 pp | | [AIKO AIKO-G670-MCH72Mw](https://comparepv.com/panel/aiko-aiko-g670-mch72mw) | 670 W | +80 W, cooler, +3.7 pp | | [Longi Solar LR7-72HVHF-670M](https://comparepv.com/panel/longi-lr7-72hvhf-670m) | 670 W | +80 W, cooler, +3.7 pp | --- Source: https://comparepv.com/panel/ja-solar-jam78s30-590-mr Not in this file, on the page: a thirty-year output simulator and alternatives filtered by how closely they match these dimensions.