Middle of its segment, modest efficiency
The JA Solar JAM66S30 480-505/MR series is designed for spaces where every square meter counts, or when installation space is limited. These modules feature monocrystalline PERC cells in a half-cut configuration, which practically translates to lower internal losses and better performance under partial shading-such as from a chimney, window frame, or neighboring trees. The application of multi-busbar technology improves current collection from the cells and enhances resistance to micro-cracks, ensuring the module maintains its performance characteristics over time. This series also offers positive power tolerance, minimizing the risk that the actual installation power will be lower than expected. The construction is designed for demanding operating conditions-robust mechanical loads and a IP68 junction box ensure trouble-free operation for years to come. This is an excellent choice for residential and commercial installations, especially when high power density, reliable yield, and durability that sets the module apart from competitors are priorities.
Ranking
Signals from the data
Residential, commercial and shaded-installations.
Tight roof space and roofs where every square metre has to count.
Bottom 12% of the PERC 450-500 W segment, against a median of 20.82%.
Bottom 17% of the PERC 450-500 W segment, against a median of 208.5.
132 half-cut cells in a 6×22 layout with 11-busbar multi-busbar (MBB) technology reduce series resistance and shading losses. Each module half operates independently, limiting the impact of partial shading from chimneys, dormers, or antennas on the full string.
Modules are shipped at or above nameplate wattage, eliminating the risk of underdelivering contracted system capacity. This protects both system designers and investors from a gap between design output and real-world energy yield from day one.
JA Solar (founded 2005) is a continuous BloombergNEF Tier-1 manufacturer with annual module production capacity exceeding 100 GWp. Tier-1 status enables non-recourse project financing and minimizes counterparty risk across a 25-year system lifetime.
IP68 protection ensures complete weatherproofing against prolonged water immersion - critical for installations exposed to heavy rainfall, condensation under roofing membranes, or high-pressure roof cleaning.
JA Solar guarantees ≥98% power output after year 1 and ≥84.8% after 25 years, with maximum annual degradation capped at 0.55%/year, plus a 12-year product warranty. The linear warranty structure eliminates the step-function power loss found in older warranty contracts and simplifies LCOE modeling.
The JAM66S30 480-505/MR series went out of production around 2023 (launched 2020). Availability is limited to distributor warehouse stock - expanding the system with identical modules or replacing failed units will become progressively harder and more expensive over a 10-15 year horizon.
PERC technology caps maximum module efficiency at 21.3%, while comparable peer products - Sunova Tangra M Pro HD and Q-SUN Qrystal N10 - achieve 22.7%. The 1.4 pp. gap translates to approximately 50-60 Wp of lost capacity over the same roof footprint (2.37 m²), a meaningful disadvantage in space-constrained installations.
The monofacial design generates no additional energy from ground albedo. In flat-roof or ground-mounted systems with a light-colored surface (concrete, gravel, snow), bifacial alternatives in the same power class can deliver 5-15% higher annual energy yield without any increase in installed area.
- At 20.4% efficiency, this panel is on par with typical PERC 450-500W modules
- At 204.3 W/m², this panel generates 4.2 W/m² less per unit area than PERC 450-500W median (208.5 W/m²)
- Temperature coefficient of -0.35%/°C matches the PERC 450-500W median
- #11680 for efficiency, #10489 for temperature performance out of 14129 panels
Specifications
Simulations
Degradation from this panel's own datasheet figures. No inverter, soiling or shading losses.
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About the JAM66S30 480-505/MR series
These answers cover the whole series. Where a figure differs, the specification above is this module's own.