--- title: "JA Solar JAM54D40-475/LB 475W Solar Panel - Specs & Review | ComparePV" description: "JA Solar JAM54D40-475/LB 475W solar panel. Specs: 23.80% efficiency, Monocrystalline cells, dimensions, warranty and temperature coefficient." source: "https://comparepv.com/panel/ja-solar-jam54d40-475-lb" updated: 2026-09-11 --- # JA Solar JAM54D40-475/LB Efficiency leader, no clear weak spot 1,089 panels in the segment TOPCon 450-500 W ## Identity - **Manufacturer:** JA Solar - **Model:** JAM54D40-475/LB - **Series:** JAM54D40 LB - **Rated power:** 475 W - **Cell technology:** TOPCon - **Bifacial:** yes ## How it compares Compared against segment TOPCon 450-500 W (1089 panels). | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Power (Wp) | 475 W | 465 W | Typical | | | Module efficiency | 23.80% | 22.52% | Strong - top 3% | 433 | | Power density | 237.7 | 225.2 | Strong - top 3% | 467 | | Temperature coefficient | -0.290 | -0.290 | Typical | 2,165 | | Weight (kg) | 22.0 kg | 24.0 kg | Strong - top 16% | | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | ### Full peer table | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Module efficiency | 23.80% | 22.52% | Strong - top 3% | 433 | | Power density | 237.7 | 225.2 | Strong - top 3% | 467 | | Temperature coefficient | -0.290 | -0.290 | Typical | 2,165 | | Weight per kWp | 46.3 | 52.2 | Strong - top 16% | 1,117 | | Performance warranty | 30 yrs | 30 yrs | Typical | 21 | ### Strengths - **23.80% module efficiency** - Top 3% of the TOPCon 450-500 W segment, against a median of 22.52%. Ranked 433rd in the whole database. - **237.7 watts per square metre** - Top 3% of the TOPCon 450-500 W segment, against a median of 225.2. Ranked 467th in the whole database. - **46.3 kg per kWp** - Top 16% of the TOPCon 450-500 W segment, against a median of 52.2. - **Best for:** Residential, commercial and shaded-installations. ## Specification ### Electrical - **Rated power (Pmax):** 475 W - **Efficiency:** 23.80 % - **Voltage at Pmax (Vmp):** 33.68 V - **Current at Pmax (Imp):** 14.11 A - **Open-circuit voltage (Voc):** 40.55 V - **Short-circuit current (Isc):** 16.19 A - **Max system voltage:** 1500 V ### Temperature - **Temperature coefficient of Pmax:** -0.290 %/degC - **Temperature coefficient of Voc:** -0.250 %/degC - **Temperature coefficient of Isc:** 0.045 %/degC - **NOCT:** 45 degC ### Cell and construction - **Cell type:** Monocrystalline - **Cell technology:** TOPCon - **Cell count:** 108 - **Bifacial:** yes - **Bifacial gain:** 10.00 ### Physical - **Length:** 1762 mm - **Width:** 1134 mm - **Thickness:** 30 mm - **Weight:** 22.0 kg - **Area:** 2.00 m2 - **Power density:** 237.7 Wp/m2 ### Warranty and degradation - **Product warranty:** 15 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:** 415 W ## Rank in the whole catalogue | Measure | Position | | --- | --- | | Efficiency | 433 of 14005 | | Power density | 467 of 14005 | | Temperature coefficient | 2165 of 14005 | | Weight | 1117 of 14005 | | Warranty | 21 of 14005 | ## Pros - **N-type TOPCon – lower LID and better thermal performance** - N-type cells exhibit LID below 0.5% (vs. ~2% for P-type PERC), with a temperature coefficient of Pmax at -0.29%/°C — among the lowest in the segment. At a typical cell temperature of 50°C, power loss is ~8.7%, versus ~10.5% for PERC modules, translating into measurably higher annual yield in warm climates. - **Bifacial glass-glass – rear-side energy gain** - The glass-glass construction with an active rear side delivers 5–15% additional energy output depending on ground albedo (white membrane, gravel, concrete). Double glass simultaneously provides superior mechanical resilience: snow load up to 5,400 Pa and wind load 2,400 Pa, making the series suitable for carport, pergola, and large flat-roof installations. - **30-year linear power warranty, 87.4% retained after 30 years** - The manufacturer guarantees annual degradation of 0.4%/year and at least 87.4% of nameplate power after 30 years of operation. Direct peer comparables — Astronergy ASTRO N7s 2.0 and Longi Hi-MO X10 Explorer — offer identical or equivalent linear power warranty terms, confirming JA Solar's competitive positioning on long-term LCOE. - **Bankability: BNEF Tier 1, 100 GW production capacity** - JA Solar has maintained BNEF Tier 1 bankable status continuously and reached 100 GW annual production capacity in 2025, placing it among the top global module manufacturers. Tier 1 status is required by most non-recourse project finance lenders, eliminating manufacturer bankability risk in commercial-scale deployments. - **Efficiency up to 23.8% – parity with segment leaders** - The top variant (475 Wp) achieves 23.8% module efficiency, matching direct peers Astronergy ASTRO N7s 2.0 (23.8%) and Sun Earth TITAN Dual GLASS (23.8%) precisely. This enables maximum energy density on constrained roof areas without the price premium typically associated with HJT technology. ## Cons - **Product warranty range: 12–15 years across variants** - Across the 9 variants in the series, the product warranty spans 12 to 15 years depending on the specific model (BF 15Y suffix vs. base variants). Variants carrying only a 12-year product warranty fall below the 15-year standard offered by Longi Hi-MO X10 Explorer and Astronergy ASTRO N7s 2.0 — buyers should verify the variant designation to avoid lower factory coverage. ## About this series JA Solar JAM54D40 LB series modules feature a glass-glass construction designed to genuinely increase energy yield not only from the front side but also from the rear-side reflected light. The key advantage of this series is the combination of **N-type cells** with the **TOPCon** architecture and the **half-cut** cell layout, resulting in better performance under partial shading and more stable energy production in varying conditions. In practice, this translates to reduced losses, higher predictability of energy output, and easier planning for self-consumption. Thanks to the **dual glass** design, the panels are more resilient to demanding installation conditions - from flat roofs to ground-mounted systems, carports, and pergolas, where the rear side can additionally contribute to the yield. This makes them an excellent choice for investors seeking maximum energy output from limited space, as well as for commercial projects where the focus is on the energy cost over the lifetime and longevity, not just the nominal power. ## Notable figures - Efficiency of 23.8% is 1.3pp above the \*\*TOPCon 450-500W\*\* median (22.5%) - At 237.7 W/m² power density, this panel generates 12.5 W/m² more per unit area than \*\*TOPCon 450-500W\*\* median (225.2 W/m²) - Temperature coefficient of -0.29%/°C matches the \*\*TOPCon 450-500W\*\* median - At 22.0 kg, this panel is 2.0 kg lighter than \*\*TOPCon 450-500W\*\* median (24.0 kg) - easier handling during installation - 80% bifaciality enables rear-side power generation, boosting yield by 4-12% on reflective surfaces ## Questions ### What does TOPCon N-type cell technology mean in the JA Solar JAM54D40 LB, and how does it compare to PERC? TOPCon (Tunnel Oxide Passivated Contact) is an N-type cell architecture that delivers lower annual degradation than PERC — approximately 0.4% per year after the first year. This means more energy produced over the full system lifetime. N-type cells are also less susceptible to PID (potential-induced degradation) and perform better at high temperatures, which matters on south-facing rooftops during summer peak production hours. ### How much extra energy can I expect from the bifacial design of the JAM54D40 LB modules? The rear side of the JAM54D40 LB modules captures light reflected from the ground surface — gravel, sand, light-colored roofing membrane, or snow. JA Solar estimates an additional bifacial gain of 5–25% depending on ground albedo and tilt angle. The highest gains are achieved in ground-mount systems and carports with light-colored surfaces where the module's rear face has good exposure to reflected irradiance. ### What warranty does the JA Solar JAM54D40 LB series come with, and what does it cover? The JAM54D40 LB series comes with a 15-year product warranty covering physical defects and workmanship, plus a 30-year linear power performance guarantee. After 30 years of operation the module retains at least 80% of its nominal output, with annual degradation of approx. 0.4%. JA Solar is a Tier 1 manufacturer, meaning the warranty is backed by a financially stable company with global service coverage. ### Are the JAM54D40 LB panels suitable for flat-roof installations, carports, or pergolas? Yes, the JAM54D40 LB series is particularly well suited for these applications. The double-glass construction provides superior mechanical strength and moisture resistance, which is critical for low-tilt or horizontal installations. On flat roofs and pergolas the bifacial rear face can generate additional energy from reflected light. At 1762×1134 mm and approx. 22 kg, the modules are compatible with standard racking and BoS hardware available on the market. ### How do JA Solar JAM54D40 LB panels handle partial shading from a chimney or dormer window? The half-cut cell layout splits each cell into two independent halves, which significantly limits the impact of localized shading on overall module output. When a chimney or dormer covers part of the panel, the unshaded cell halves continue operating without disruption. The TOPCon N-type technology also maintains stable output under diffuse light conditions, improving annual energy yield in climates with frequent overcast days. ### What is the maximum power output of the JA Solar JAM54D40 LB, and is this series still available? The JAM54D40 LB series is active and currently available. The peak power rating reaches up to 475 Wp, delivering module efficiency above 23% at compact dimensions of 1762×1134 mm. This makes it a strong choice both for residential prosumer systems with limited roof space and for commercial installations where low LCOE and long-term durability are the primary selection criteria. ## Datasheet [Manufacturer datasheet (PDF)](https://comparepv.com/datasheets/e5a72f2e6fa3-7169ab9dd040.pdf) ## Alternatives | Panel | Power | How it differs | | --- | --- | --- | | [Longi Solar LR7-54HJD-510M](https://comparepv.com/panel/longi-lr7-54hjd-510m) | 510 W | +35 W, cooler, +1.2 pp | | [AIKO AIKO-A495-MCE54Mw](https://comparepv.com/panel/aiko-aiko-a495-mce54mw) | 495 W | +20 W, cooler, +1.0 pp | | [Longi Solar LR7-54HJD-505M](https://comparepv.com/panel/longi-lr7-54hjd-505m) | 505 W | +30 W, cooler, +0.9 pp | | [AIKO AIKO-A490-MCE54Mw](https://comparepv.com/panel/aiko-aiko-a490-mce54mw) | 490 W | +15 W, cooler, +0.7 pp | | [Longi Solar LR7-54HJD-500M](https://comparepv.com/panel/longi-lr7-54hjd-500m) | 500 W | +25 W, cooler, +0.7 pp | | [Talesun CIPRO-TN9C54M-500W](https://comparepv.com/panel/talesun-cipro-tn9c54m-500w) | 500 W | +25 W, cooler, +0.7 pp | | [JA Solar NS-420MH-108](https://comparepv.com/panel/ja-solar-ns-420mh-108) | 420 W | -55 W, heavier, -2.8 pp | | [JA Solar JAM54D41-430/LB](https://comparepv.com/panel/ja-solar-jam54d41-430-lb-1) | 430 W | -45 W, -2.3 pp | | [JA Solar JAM54S40-435/LR](https://comparepv.com/panel/ja-solar-jam54s40-435-lr) | 435 W | -40 W, lighter, -2.0 pp | | [JA Solar JAM54S40-440/LR](https://comparepv.com/panel/ja-solar-jam54s40-440-lr) | 440 W | -35 W, lighter, -1.8 pp | --- Source: https://comparepv.com/panel/ja-solar-jam54d40-475-lb 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.