--- title: "JA Solar JAM78D40-620/GB/1500V Solar Panel: Specs & Datasheet | ComparePV" description: "JA Solar JAM78D40-620/GB/1500V solar panel. Specs: 22.20% efficiency, Monocrystalline cells, dimensions, warranty and temperature coefficient." source: "https://comparepv.com/panel/ja-solar-jam78d40-620-gb-1500v" image: "https://comparepv.com/og/panel/ja-solar-jam78d40-620-gb-1500v.png" updated: 2026-09-11 --- # JA Solar JAM78D40-620/GB/1500V Middle of its segment, weak in heat 368 panels in the segment N-type 600-650 W ## Identity - **Manufacturer:** JA Solar - **Model:** JAM78D40-620/GB/1500V - **Series:** DEEP BLUE 4.0 JAM78D40 605-630/GB/1500V Series - **Rated power:** 620 W - **Cell technology:** N-type - **Bifacial:** yes ## How it compares Compared against segment N-type 600-650 W (368 panels). | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Power (Wp) | 620 W | 625 W | Typical | | | Module efficiency | 22.20% | 22.77% | Weak - bottom 15% | 5,881 | | Power density | 221.8 | 227.7 | Weak - bottom 12% | 5,933 | | Temperature coefficient | -0.300 | -0.290 | Weak - bottom 11% | 6,152 | | Weight (kg) | 33.4 kg | 32.8 kg | Typical | | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | ### Full peer table | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Module efficiency | 22.20% | 22.77% | Weak - bottom 15% | 5,881 | | Power density | 221.8 | 227.7 | Weak - bottom 12% | 5,933 | | Temperature coefficient | -0.300 | -0.290 | Weak - bottom 11% | 6,152 | | Weight per kWp | 53.9 | 52.8 | Typical | 8,089 | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | ### Watch out for - **-0.300 %/°C temperature coefficient** - Bottom 11% of the N-type 600-650 W segment, against a median of -0.290. - **221.8 watts per square metre** - Bottom 12% of the N-type 600-650 W segment, against a median of 227.7. - **22.20% module efficiency** - Bottom 15% of the N-type 600-650 W segment, against a median of 22.77%. - **Best for:** Utility-scale and commercial. - **Not ideal for:** Hot climates, roofs where every square metre has to count and tight roof space. ## Specification ### Electrical - **Rated power (Pmax):** 620 W - **Efficiency:** 22.20 % - **Voltage at Pmax (Vmp):** 46.20 V - **Current at Pmax (Imp):** 13.42 A - **Open-circuit voltage (Voc):** 55.34 V - **Short-circuit current (Isc):** 14.30 A - **Max system voltage:** 1500 V ### Temperature - **Temperature coefficient of Pmax:** -0.300 %/degC - **Temperature coefficient of Voc:** -0.260 %/degC - **Temperature coefficient of Isc:** 0.046 %/degC - **NOCT:** 45 degC ### Cell and construction - **Cell type:** Monocrystalline - **Cell technology:** N-type - **Cell count:** 156 - **Bifacial:** yes - **Bifacial gain:** 7.93 ### Physical - **Length:** 2465 mm - **Width:** 1134 mm - **Thickness:** 35 mm - **Weight:** 33.4 kg - **Area:** 2.80 m2 - **Power density:** 221.8 Wp/m2 ### Warranty and degradation - **Product warranty:** 12 years - **Performance warranty:** 30 years - **Output guaranteed at end of warranty:** 87.4 % - **First-year degradation:** 1.00 % - **Annual degradation:** 0.40 % - **Output after 30 years:** 542 W ## Rank in the whole catalogue | Measure | Position | | --- | --- | | Efficiency | 5881 of 14129 | | Power density | 5933 of 14129 | | Temperature coefficient | 6152 of 14129 | | Weight | 8089 of 14129 | | Warranty | 21 of 14129 | ## Pros - **N-type Bycium+ with low degradation** - 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. - **Bifacial glass-glass construction** - 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. - **30-year linear power warranty** - 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. - **1500 V DC compatibility - lower BoS costs** - 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. - **BNEF Tier-1 Bankable manufacturer** - 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. ## Cons - **Discontinued series (since 2023)** - 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. - **Max efficiency 22.5% - below peer leaders** - 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. ## About this series 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. ## Notable figures - 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 ## Questions ### What is the Bycium+ technology used in the JA Solar DEEP BLUE 4.0 JAM78D40 series and why does it matter? Bycium+ is JA Solar's proprietary N-type TOPCon cell technology. Compared to mainstream PERC cells, it delivers higher module efficiency - up to 22.5% in this series - and a significantly lower long-term degradation rate. A key advantage is strong resistance to LID and LeTID phenomena, which cause permanent power loss in older technologies. For investors, this translates to more energy generated over the entire operational lifetime of the system. ### How does the bifacial glass-glass construction of the JAM78D40 605-630/GB work and when is it worth choosing? The bifacial design allows the module to absorb light from both the front and rear sides - including light reflected from lighter surfaces such as gravel, sand, or snow. The glass-glass encapsulation (replacing the standard glass-backsheet design) further improves mechanical strength and moisture resistance. The JAM78D40 series performs best in ground-mount installations with elevated racking, where the bifacial gain can realistically add several to over ten percent to annual energy yield. ### What warranty comes with the JA Solar DEEP BLUE 4.0 JAM78D40 605-630/GB panels? The manufacturer provides a 12-year product warranty covering material and workmanship defects, along with a 30-year linear power output warranty. Over those 30 years, module power should not fall below the levels specified in the warranty curve. This is one of the longer power warranties available on the market, a direct result of the inherently more stable N-type cell technology compared to older panel generations. ### Do the JAM78D40 630 Wp panels handle high summer temperatures well, and how much power do they lose? Temperature affects every PV module, but the DEEP BLUE 4.0 series stands out with a temperature coefficient of power of just -0.30%/°C. This means the module loses only 0.30% of its rated power for every degree Celsius the cell temperature rises above 25°C. Older-generation technologies typically range from -0.35% to -0.40%/°C, so the difference on hot summer days is measurable and directly impacts annual energy yield. ### Which inverters and racking systems are compatible with the JA Solar JAM78D40 605-630/GB/1500V modules? The series is rated for 1500V DC systems, which is today's standard for commercial and utility-scale installations. Module dimensions are 2465 × 1134 × 35 mm and weight is 33.4 kg. The panels are compatible with central and string inverters rated for 1500V, including models from SMA, Sungrow, Huawei, and ABB. Always verify with your racking system manufacturer that the structure meets wind and snow load requirements for your specific location. ### Is the JA Solar DEEP BLUE 4.0 JAM78D40 605-630/GB/1500V series still available for purchase? The JAM78D40 605-630/GB/1500V series has been discontinued. It may still be available from distributors with remaining warehouse stock. Before purchasing, verify current inventory levels and confirm that any units acquired are covered by the full manufacturer warranty. JA Solar's newer N-type Bycium+ series serve as successors, offering the same platform with higher wattage ratings. ## Datasheet [Manufacturer datasheet (PDF)](https://comparepv.com/datasheets/20220928043052535-47b2780b727d.pdf) ## Alternatives | Panel | Power | How it differs | | --- | --- | --- | | [AIKO AIKO-A650-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a650-mae72mw) | 650 W | Cooler, lighter, +3.0 pp | | [AIKO AIKO-A645-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a645-mae72mw) | 645 W | Cooler, lighter, +2.8 pp | | [AIKO AIKO-G670-MCH72Mw](https://comparepv.com/panel/aiko-aiko-g670-mch72mw) | 670 W | +50 W, lighter, +2.6 pp | | [Longi Solar LR7-72HVHF-670M](https://comparepv.com/panel/longi-lr7-72hvhf-670m) | 670 W | +50 W, lighter, +2.6 pp | | [AIKO AIKO-A640-MAE72Mw](https://comparepv.com/panel/aiko-aiko-a640-mae72mw) | 640 W | Cooler, lighter, +2.6 pp | | [Jinko Solar JKM650-670N-66QL6-BDV (670W class)](https://comparepv.com/panel/jinko-solar-jkm650-670n-66ql6-bdv-670w-class) | 670 W | +50 W, cooler, +2.6 pp | | [JA Solar JAM78S30-580/MR](https://comparepv.com/panel/ja-solar-jam78s30-580-mr) | 580 W | Hotter, -1.5 pp, -5 yr warranty | | [JA Solar JAM78S30-585/MR](https://comparepv.com/panel/ja-solar-jam78s30-585-mr) | 585 W | Hotter, -1.3 pp, -5 yr warranty | | [JA Solar JAM78S30-590/MR](https://comparepv.com/panel/ja-solar-jam78s30-590-mr) | 590 W | Hotter, -1.1 pp, -5 yr warranty | | [JA Solar JAM78S30-595/MR](https://comparepv.com/panel/ja-solar-jam78s30-595-mr) | 595 W | Hotter, -0.9 pp, -5 yr warranty | | [JA Solar JAM78S30-600/MR](https://comparepv.com/panel/ja-solar-jam78s30-600-mr) | 600 W | Hotter, -0.7 pp, -5 yr warranty | | [AIKO AIKO-A680-MDE72Mw](https://comparepv.com/panel/aiko-aiko-a680-mde72mw) | 680 W | +60 W, lighter, +3.0 pp | | [AIKO AIKO-A675-MDE72Mw](https://comparepv.com/panel/aiko-aiko-a675-mde72mw) | 675 W | +55 W, lighter, +2.8 pp | | [AIKO AIKO-A700-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a700-mae78dw) | 700 W | +80 W, cooler, +2.8 pp | | [WINAICO WST-675BKX72-A2](https://comparepv.com/panel/winaico-wst-675bkx72-a2) | 675 W | +55 W, cooler, +2.8 pp | | [AIKO AIKO-A695-MAE78Dw](https://comparepv.com/panel/aiko-aiko-a695-mae78dw) | 695 W | +75 W, cooler, +2.7 pp | --- Source: https://comparepv.com/panel/ja-solar-jam78d40-620-gb-1500v Not in this file, on the page: the I-V and temperature curves lifted from the manufacturer's datasheet, a thirty-year output simulator, a bifacial gain calculator and alternatives filtered by how closely they match these dimensions.