Middle of its segment, weak in heat
The JA Solar DEEP BLUE 4.0 JAM78D40 605-630/GB/1500V series focuses on delivering maximum performance in the most demanding commercial and industrial projects. The use of n-type cells in proprietary Bycium+ technology allows for higher efficiency while limiting power degradation over time, which directly translates into better financial results for the power plant. Thanks to the bifacial glass-glass design, these modules effectively utilize light reflected from the ground, making them unrivaled in large-scale ground-mounted installations. The innovative SMBB busbar improves conductivity and minimizes internal losses, effectively solving the problem of power drops at high ambient temperatures. Unlike standard products, this series offers exceptional resistance to LID and LeTID phenomena, guaranteeing the stability of technical parameters for decades. This product is dedicated to investors seeking the lowest levelized cost of energy LCOE, while providing full compatibility with mounting systems and inverters operating at 1500V. This solution eliminates compromises between mechanical strength and cell packing density, offering reliability that is hard to find in older generations of panels. An investment in this series is a guarantee of the highest energy yields from every available square meter of surface area while maintaining the highest safety standards.
Ranking
Signals from the data
Utility-scale and commercial.
Hot climates, roofs where every square metre has to count and tight roof space.
Bottom 11% of the N-type 600-650 W segment, against a median of -0.290.
Bottom 12% of the N-type 600-650 W segment, against a median of 227.7.
Bottom 15% of the N-type 600-650 W segment, against a median of 22.77%.
Bycium+ N-type cells are immune to LID and LeTID phenomena and feature a superior temperature coefficient (-0.30%/°C vs. -0.35%/°C for standard p-type PERC). A one-year outdoor yield test conducted by JA Solar in Hainan showed 3.9% higher energy generation versus a bifacial PERC module under identical irradiance conditions.
The dual-glass design (2 mm tempered front and rear) captures albedo-reflected light from the ground surface, increasing annual energy yield in utility-scale ground-mount installations. Glass-glass structure also provides superior mechanical strength and moisture ingress resistance compared to conventional backsheet modules.
JA Solar guarantees degradation of <1% in year one and <0.4%/year thereafter, ensuring a minimum of 87.4% of rated power after 30 years. The market standard remains 25-year warranties (often to 84.8% Pnom), making the additional 5 years of linear coverage a tangible LCOE advantage.
A 1500 V system voltage allows longer strings - fewer inverters, thinner DC cables, and reduced transmission losses - compared to 1000 V installations, directly reducing Balance of System infrastructure costs in commercial and utility-scale projects.
JA Solar holds Tier-1 Bankable Manufacturer status per Bloomberg NEF, enabling straightforward project financing by banks and infrastructure funds without additional manufacturer audits. The company has operated since 2005 and ranks among the world's top PV producers by shipment volume.
The JAM78D40 605-630/GB series ended production in 2023 and was superseded by the DeepBlue 4.0 Pro generation. This means limited market availability, no supply continuity for farm expansions, and potential difficulty sourcing replacement modules after 2026-2027 once distributor inventories are depleted.
The series peaks at 22.5% module efficiency, while direct competitors at the same 630 Wp power class deliver significantly more: Canadian Solar TOPBiHiKu6 at 23.3% and Jinko Tiger Neo 66HL4M-BDV at 23.32%. The ~0.8 percentage-point efficiency gap translates to greater land area requirements for equivalent installed capacity, which carries real economic weight in land-constrained projects.
- At 22.2% efficiency, this panel is 0.6pp below the N-type 600-650W median of 22.8%
- Power density of 221.8 W/m² is 5.9 W/m² below N-type 600-650W median (227.7 W/m²) - needs more roof space
- Temperature coefficient of -0.30%/°C matches the N-type 600-650W median
- 80% bifaciality enables rear-side power generation, boosting yield by 4-12% on reflective surfaces
- #5881 for efficiency, #6152 for temperature performance out of 14129 panels
Specifications
Datasheet charts
Measured curves published by JA Solar in this model's datasheet. A chart carrying a wattage was measured on that variant alone - only the ones that describe 620 Wp appear here. The rest cover the whole series.
Simulations
Degradation from this panel's own datasheet figures. No inverter, soiling or shading losses.
Model: bifaciality × albedo × 0.6 view factor. A first-order estimate, not a yield simulation.
Found 616 panels of the same or similar size to this one, within ±10 mm. See them here Found 616 panels of the same or similar size to this one, within ±25 mm. See them here Found 616 panels of the same or similar size to this one, within ±50 mm. See them here Found 1838 panels of the same or similar size to this one, within ±100 mm. See them here
About the DEEP BLUE 4.0 JAM78D40 605-630/GB/1500V Series series
These answers cover the whole series. Where a figure differs, the specification above is this module's own.