--- title: "JA Solar JAM60S21-365/MR/1000V 365W Solar Panel - Specs & Review | ComparePV" description: "JA Solar JAM60S21-365/MR/1000V 365W solar panel. Specs: 19.60% efficiency, Monocrystalline cells, dimensions, warranty and temperature coefficient." source: "https://comparepv.com/panel/shanghai-ja-solar-technology-co-ltd-jam60s21-365-mr-1000v" image: "https://comparepv.com/og/panel/shanghai-ja-solar-technology-co-ltd-jam60s21-365-mr-1000v.png" updated: 2026-09-11 --- # JA Solar JAM60S21-365/MR/1000V Light for its output, no clear weak spot 579 panels in the segment PERC 350-400 W ## Identity - **Manufacturer:** JA Solar - **Model:** JAM60S21-365/MR/1000V - **Series:** JAM60S21 365-390/MR/1000V - **Rated power:** 365 W - **Cell technology:** PERC ## How it compares Compared against segment PERC 350-400 W (579 panels). | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Power (Wp) | 365 W | 380 W | Weak - bottom 20% | | | Module efficiency | 19.60% | 19.90% | Typical | 12,589 | | Power density | 196.1 | 199.0 | Typical | 12,583 | | Temperature coefficient | -0.350 | -0.350 | Typical | 10,419 | | Weight (kg) | 18.8 kg | 21.4 kg | Strong - top 13% | | | Performance warranty | 25 yrs | 25 yrs | Typical | 9,798 | ### Full peer table | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Module efficiency | 19.60% | 19.90% | Typical | 12,589 | | Power density | 196.1 | 199.0 | Typical | 12,583 | | Temperature coefficient | -0.350 | -0.350 | Typical | 10,419 | | Weight per kWp | 51.5 | 55.8 | Strong - top 13% | 4,878 | | Performance warranty | 25 yrs | 25 yrs | Typical | 9,798 | ### Strengths - **51.5 kg per kWp** - Top 13% of the PERC 350-400 W segment, against a median of 55.8. - **Best for:** Residential, commercial and shaded-installations. ## Specification ### Electrical - **Rated power (Pmax):** 365 W - **Efficiency:** 19.60 % - **Voltage at Pmax (Vmp):** 33.96 V - **Current at Pmax (Imp):** 10.75 A - **Open-circuit voltage (Voc):** 41.13 V - **Short-circuit current (Isc):** 11.30 A - **Max system voltage:** 1000 V ### Temperature - **Temperature coefficient of Pmax:** -0.350 %/degC - **Temperature coefficient of Voc:** -0.272 %/degC - **Temperature coefficient of Isc:** 0.044 %/degC - **NOCT:** 45 degC ### Cell and construction - **Cell type:** Monocrystalline - **Cell technology:** PERC - **Cell count:** 120 ### Physical - **Length:** 1769 mm - **Width:** 1052 mm - **Thickness:** 30 mm - **Weight:** 18.8 kg - **Area:** 1.86 m2 - **Power density:** 196.1 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:** 299 W ## Rank in the whole catalogue | Measure | Position | | --- | --- | | Efficiency | 12589 of 14005 | | Power density | 12583 of 14005 | | Temperature coefficient | 10419 of 14005 | | Weight | 4878 of 14005 | | Warranty | 9798 of 14005 | ## Pros - **MBB half-cut PERC architecture** - The combination of 9 busbars (multi-busbar) with a half-cut cell layout (120 cells) shortens current paths, reduces resistive losses, and lowers hot-spot risk. The result is improved partial-shading tolerance and better long-term reliability compared to conventional full-cell modules with 4–6 busbars. - **BNEF Tier-1 — fully bankable** - JA Solar has maintained BNEF Tier-1 status for over a decade and operates more than 80 GWp of annual production capacity (2025–2026 data). Modules from this series qualify for project financing by major lenders without additional security requirements — a key factor for residential and small commercial installations funded through loans. - **Full Black variant (/MR designation)** - The MR suffix indicates a black frame and black backsheet, allowing seamless integration with dark roof tiles and bitumen shingles. The all-black aesthetic is especially valued on street-facing roofs or properties subject to local planning or heritage guidelines. - **25-year linear power warranty** - The manufacturer guarantees a minimum of 84.8% of nominal power after 25 years of operation (linear degradation not exceeding ~0.55%/year after Year 1). This warranty is the segment standard for PERC modules and sufficient to cover the typical loan repayment period for a residential PV system. ## Cons - **Discontinued series (2023)** - The JAM60S21 line ended production in 2023. Sourcing new modules is increasingly difficult, and matching an identical module for system expansion or warranty replacement is effectively impossible. Technical support and availability of spare parts (bypass diodes, MC4 connectors) will progressively decline. - **25-year power retention below top-tier peers** - The guaranteed 84.8% output after 25 years is significantly weaker than the LG NeON R Prime 390W (HJT technology), which guarantees 92.5% over the same period. For a 10 kWp system, this difference translates to approximately 770 Wp less real output after 25 years of operation. - **Efficiency below direct peer comparables** - The series tops out at 21.0% efficiency (390 Wp), while comparable power-class peers deliver: Meyer Burger Glass — 21.2%, Phono Solar Twinplus — 21.3%, LG NeON R Prime — 21.5%. On a typical 20 m² roof, the 0.5 pp gap vs. LG equates to roughly 10 Wp less, or approximately 10–12 kWh lower annual yield. - **12-year product warranty** - A 12-year materials and workmanship warranty was market-standard in 2020, but the industry has since shifted upward — the LG NeON R Prime in the same power/price segment offered a 25-year product warranty. The shorter coverage increases the investor's financial risk for any manufacturing defects that emerge after Year 12. ## About this series JA Solar JAM60S21 365-390/MR/1000V modules are monocrystalline panels featuring a half-cell design, engineered for reliable performance in real rooftop conditions - even when parts of the roof are intermittently shaded (e.g., by chimneys, roof edges, or trees). The use of PERC cells with **multi-busbar** technology enhances current collection from the cell surface and minimizes losses, resulting in more predictable energy output throughout the day. The **half-cell** structure reduces internal current stress within the module, helping to lower the risk of localized overheating and supporting long-term reliability. This series is also chosen where aesthetics matter - available in **full black** variants that blend better with modern rooftops. An additional advantage is **mechanical load resistance**, crucial for wind and accumulated snow. These modules are suitable for residential and small commercial installations, especially where longevity, good performance in heat, and reduced sensitivity to suboptimal installation conditions are priorities. ## Notable figures - At 19.6% efficiency, this panel is on par with typical \*\*PERC 0-400W\*\* modules - At 196.1 W/m² power density, roof space requirements are typical for \*\*PERC 0-400W\*\* panels - At -0.35%/°C, hot weather performance is typical for \*\*PERC 0-400W\*\* panels - Weight of 18.8 kg (1.7 kg below \*\*PERC 0-400W\*\* median of 20.5 kg) allows easier transport and roof mounting - #12589 for efficiency, #10419 for temperature performance out of 14005 panels ## Questions ### Is the JA Solar JAM60S21 365-390/MR/1000V series still available for purchase? The JAM60S21 365-390/MR/1000V series has been officially discontinued by JA Solar. Some distributors may still carry limited stock, but availability is shrinking. For a new installation, we recommend exploring current JA Solar series with comparable specifications, as they offer better parts availability and ongoing warranty support. ### What warranty comes with the JA Solar JAM60S21 390W panels? JA Solar provides a 12-year product warranty and a 25-year linear power output warranty for the JAM60S21 series. After 25 years of operation, the modules should still produce at least 80.7% of their rated power. Both warranties cover material and manufacturing defects; damage caused by improper installation is excluded. ### Do the JAM60S21 MR panels handle partial shading from a chimney or trees well? Yes. The half-cut cell design splits each cell in half, so shading one portion of the module does not shut down the rest. Combined with multi-busbar technology, which shortens the current path across each cell, the JAM60S21 series maintains better energy output under irregular shading than older full-cell modules — an important advantage on rooftops with chimneys, dormers, or nearby trees. ### What is PERC with multi-busbar technology in the JAM60S21 panels, and why does it matter? PERC cells feature a reflective rear passivation layer that bounces unabsorbed light back into the junction, pushing module efficiency up to approximately 19.6% for the 390 W variant. Multi-busbar means more, thinner busbars per cell, which reduces resistive losses, lowers mechanical stress on the cells, and helps minimize the risk of microcracks over the module's lifetime. Together, the technologies result in more predictable daily energy yield. ### Can the JA Solar JAM60S21 390W panel withstand heavy snow and strong wind on a rooftop? The JAM60S21 series is rated for a front snow load of 5,400 Pa and a rear wind suction load of 2,400 Pa, covering extreme Central European climate conditions. At 20.2 kg and 1,769 × 1,052 mm, the module is compact enough for standard racking systems. When correctly installed, the risk of mechanical damage from snowpack or high winds is minimal. ### Is the JAM60S21 MR series available in an all-black version, and does it suit a dark roof? Yes, JA Solar offered all-black variants with a black frame and black backsheet. This finish blends visually into dark roof tiles or bituminous shingles, making it a popular choice for homeowners who prioritize aesthetics. The power output and technical specifications of the all-black variant are identical to the standard version, so the color choice has no effect on system performance. ## Datasheet [Manufacturer datasheet (PDF)](https://comparepv.com/datasheets/20220415024414123-8b4f30eb6993.pdf) ## Alternatives | Panel | Power | How it differs | | --- | --- | --- | | [JA Solar NS-330MH-80](https://comparepv.com/panel/ja-solar-ns-330mh-80) | 330 W | Cooler, lighter, +3.5 pp | | [PolyCrown Solar Tech NS-330MH-80](https://comparepv.com/panel/polycrown-solar-tech-ns-330mh-80) | 330 W | Cooler, lighter, +3.5 pp | | [Gamko New Energy GKA210M320W](https://comparepv.com/panel/gamko-new-energy-gka210m320w) | 320 W | -45 W, +3.4 pp, +5 yr warranty | | [Gamko New Energy GKA210M340W](https://comparepv.com/panel/gamko-new-energy-gka210m340w) | 340 W | Lighter, +3.4 pp, +5 yr warranty | | [Gamko New Energy GKA210M360W](https://comparepv.com/panel/gamko-new-energy-gka210m360w) | 360 W | Lighter, +3.4 pp, +5 yr warranty | | [Gamko New Energy GKA210M380W (1/4\*4\*38)](https://comparepv.com/panel/gamko-new-energy-gka210m380w-1-4-4-38) | 380 W | Lighter, +3.4 pp, +5 yr warranty | | [Gamko New Energy GKA210M400W (1/2\*4\*20)](https://comparepv.com/panel/gamko-new-energy-gka210m400w-1-2-4-20) | 400 W | +35 W, +3.4 pp, +5 yr warranty | | [Gamko New Energy GKA210M400W (1/4\*4\*40)](https://comparepv.com/panel/gamko-new-energy-gka210m400w-1-4-4-40) | 400 W | +35 W, +3.4 pp, +5 yr warranty | | [Gamko New Energy GKA210M380W (1/2\*4\*19)](https://comparepv.com/panel/gamko-new-energy-gka210m380w-1-2-4-19) | 380 W | Lighter, +3.4 pp, +5 yr warranty | | [Maxeon SPR-MAX3-400-COM](https://comparepv.com/panel/maxeon-spr-max3-400-com) | 400 W | Cooler, +3.0 pp, +15 yr warranty | | [JA Solar JAM60D20-360/MB/1500V](https://comparepv.com/panel/shanghai-ja-solar-technology-co-ltd-jam60d20-360-mb-1500v) | 360 W | Heavier, -0.3 pp, +5 yr warranty | | [JA Solar JAM60D20-365/MB/1500V](https://comparepv.com/panel/shanghai-ja-solar-technology-co-ltd-jam60d20-365-mb-1500v) | 365 W | Heavier, +5 yr warranty | | [JA Solar JAM60D20-370/MB/1500V](https://comparepv.com/panel/shanghai-ja-solar-technology-co-ltd-jam60d20-370-mb-1500v) | 370 W | Heavier, +5 yr warranty | | [JA Solar JAM60S21-370/MR/1000V](https://comparepv.com/panel/shanghai-ja-solar-technology-co-ltd-jam60s21-370-mr-1000v) | 370 W | +0.3 pp | | [JA Solar JAM60S20-375/MR](https://comparepv.com/panel/ja-solar-jam60s20-375-mr-1) | 375 W | +10 W, heavier, +0.6 pp | | [JA Solar JAM60D20-375/MB/1500V](https://comparepv.com/panel/shanghai-ja-solar-technology-co-ltd-jam60d20-375-mb-1500v) | 375 W | Heavier, +0.5 pp, +5 yr warranty | | [Longi Solar LR7-54HJD-510M](https://comparepv.com/panel/longi-lr7-54hjd-510m) | 510 W | +145 W, cooler, +5.4 pp | --- Source: https://comparepv.com/panel/shanghai-ja-solar-technology-co-ltd-jam60s21-365-mr-1000v Not in this file, on the page: a thirty-year output simulator and alternatives filtered by how closely they match these dimensions.