--- title: "JA Solar JAM54D41-445/LR vs JA Solar JAM66D46-740/LB - Solar Panel Comparison | ComparePV" description: "Compare JA Solar JAM54D41-445/LR vs JA Solar JAM66D46-740/LB side by side: what actually differs, output when it is hot, thirty-year production, and the full specification." source: "https://comparepv.com/compare/ja-solar-jam54d41-445-lr/ja-solar-jam66d46-740-lb" updated: 2026-09-11 --- # JA Solar JAM54D41-445/LR vs JA Solar JAM66D46-740/LB JAM66D46-740/LB leads on the differences that matter The largest is module efficiency: 1.50 pp more efficient. 5 of 19 comparable parameters are identical. ## The two panels | Attribute | A | B | | --- | --- | --- | | Panel | [JA Solar JAM54D41-445/LR](https://comparepv.com/panel/ja-solar-jam54d41-445-lr) | [JA Solar JAM66D46-740/LB](https://comparepv.com/panel/ja-solar-jam66d46-740-lb) | | Manufacturer | JA Solar | JA Solar | | Power | 445 Wp | 740 Wp | | Efficiency | 22.30 % | 23.80 % | | Technology | TOPCon | TOPCon | ## Where they differ Ranked by how much the difference matters, not by datasheet order. | Parameter | JAM54D41-445/LR | JAM66D46-740/LB | Difference | | --- | --- | --- | --- | | Module efficiency | 22.30 % | 23.80 % | +1.50 pp for JAM66D46-740/LB | | Rated power | 445 Wp | 740 Wp | +295 W for JAM66D46-740/LB | | Power density | 222.7 Wp/m² | 238.2 Wp/m² | +15.5 Wp/m² for JAM66D46-740/LB | | Weight | 22.0 kg | 38.2 kg | -16.2 kg for JAM54D41-445/LR | | Product warranty | 15 yrs | 12 yrs | +3 yrs for JAM54D41-445/LR | | Open-circuit voltage | 39.10 V | 49.80 V | 10.70 V apart | | Short-circuit current | 14.40 A | 18.73 A | 4.33 A apart | | Module area | 1.998 m² | 3.106 m² | 1.108 m² apart | | Voltage at max power | 32.65 V | 41.96 V | 9.31 V apart | | Current at max power | 13.63 A | 17.64 A | 4.01 A apart | | Cell count | 108 | 132 | 24 cells apart | | Weight per kWp | 49.4 kg/kWp | 51.6 kg/kWp | -2.2 kg/kWp for JAM54D41-445/LR | | Bifacial | No | Yes | No vs Yes | | Dimensions | 1762x1134x30 mm | 2384x1303x33 mm | 1762x1134x30 mm vs 2384x1303x33 mm | ## Every compared parameter | Parameter | JAM54D41-445/LR | JAM66D46-740/LB | | --- | --- | --- | | Rated power | 445 Wp | 740 Wp | | Module efficiency | 22.30 % | 23.80 % | | Power density | 222.7 Wp/m² | 238.2 Wp/m² | | Open-circuit voltage | 39.10 V | 49.80 V | | Voltage at max power | 32.65 V | 41.96 V | | Short-circuit current | 14.40 A | 18.73 A | | Current at max power | 13.63 A | 17.64 A | | Temperature coefficient | -0.290 %/°C | -0.290 %/°C | | Dimensions | 1762x1134x30 mm | 2384x1303x33 mm | | Module area | 1.998 m² | 3.106 m² | | Weight | 22.0 kg | 38.2 kg | | Weight per kWp | 49.4 kg/kWp | 51.6 kg/kWp | | Product warranty | 15 yrs | 12 yrs | | Performance warranty | 30 yrs | 30 yrs | | Annual degradation | 0.40 %/yr | 0.40 %/yr | | Cell technology | TOPCon | TOPCon | | Cell type | Monocrystalline | Monocrystalline | | Cell count | 108 | 132 | | Bifacial | No | Yes | ## Thirty-year yield Each panel's own declared degradation curve, at 1,200 kWh/kWp a year Same temp coeff. for both panels (-0.290 %/°C), so a warmer roof scales both curves by the same factor: the totals fall together and neither panel gains on the other. - **Cumulative output, JAM54D41-445/LR:** 14,931 kWh - **Cumulative output, JAM66D46-740/LB:** 24,828 kWh - **Gap:** 9,897 kWh ## Output when hot | Condition | Cell temperature | JAM54D41-445/LR | JAM66D46-740/LB | Retained | | --- | --- | --- | --- | --- | | Standard test conditions | 25 °C | 445 W | 740 W | 100.0% of rated power | | Cool, bright day | 40 °C | 426 W | 708 W | 95.7% of rated power | | Typical summer roof | 55 °C | 406 W | 676 W | 91.3% of rated power | | Hot roof | 70 °C | 387 W | 643 W | 87.0% of rated power | ## Against the whole database | Measure | JAM54D41-445/LR | JAM66D46-740/LB | Out of | Note | | --- | --- | --- | --- | --- | | Efficiency | #5,100 | #433 | 14,005 | JAM66D46-740/LB leads by 4,667 places | | Power density | #5,302 | #431 | 14,005 | JAM66D46-740/LB leads by 4,871 places | | Heat behaviour | #2,165 | #2,165 | 14,005 | Tied - the same position in the database | | Weight | #2,959 | #4,997 | 14,005 | JAM54D41-445/LR leads by 2,038 places | | Warranty | #21 | #21 | 14,005 | Tied - the same position in the database | | Overall | #8,801 | #185 | 14,005 | JAM66D46-740/LB leads by 8,616 places | ## Questions ### Which panel is better: JA Solar JAM54D41-445/LR or JA Solar JAM66D46-740/LB? According to our database: **JA Solar JAM66D46-740/LB** has higher module efficiency (**23.80%** vs **22.30%**). See the full spec comparison and 30-year energy simulation above for a complete picture. ### What is the efficiency of JA Solar JAM54D41-445/LR and JA Solar JAM66D46-740/LB? **JA Solar JAM54D41-445/LR** has a module efficiency of **22.30%**, while **JA Solar JAM66D46-740/LB** is **23.80%**. Higher efficiency means more electricity from the same roof area - useful when space is limited. ### What cell technology does JA Solar JAM54D41-445/LR use vs JA Solar JAM66D46-740/LB? **JA Solar JAM54D41-445/LR** uses **TOPCon** cells; **JA Solar JAM66D46-740/LB** uses **TOPCon**. Modern **n-type** technologies (**TOPCon**, **HJT**, BC) typically deliver higher efficiency and lower degradation compared to older **PERC** (p-type) cells. ### What is the warranty on JA Solar JAM54D41-445/LR and JA Solar JAM66D46-740/LB? **JA Solar JAM54D41-445/LR** has a **30 years** power warranty; **JA Solar JAM66D46-740/LB** has a **30 years** power warranty. The power warranty guarantees a minimum percentage of rated output at the end of the warranty period (typically 80**-87%**). Product (materials) warranties are usually shorter. ### Are JA Solar JAM54D41-445/LR and JA Solar JAM66D46-740/LB bifacial panels? **JA Solar JAM66D46-740/LB** is bifacial (captures light from both faces); **JA Solar JAM54D41-445/LR** is monofacial. Bifacial panels work best on ground mounts or raised structures with a light-coloured surface underneath. ## Related comparisons - [JA Solar JAM54D41-445/LR vs JA Solar JAM54D41-455/LR](https://comparepv.com/compare/ja-solar-jam54d41-445-lr/ja-solar-jam54d41-455-lr) - 4 differences, the largest is module efficiency - [JA Solar JAM54D41-445/LR vs JA Solar JAM54D41-450/LR](https://comparepv.com/compare/ja-solar-jam54d41-445-lr/ja-solar-jam54d41-450-lr) - 2 differences, the largest is module efficiency - [JA Solar JAM54D41-445/LR vs JA Solar JAM54D41-440/LR](https://comparepv.com/compare/ja-solar-jam54d41-445-lr/ja-solar-jam54d41-440-lr) - One difference: module efficiency - [JA Solar JAM66D46-740/LB vs JA Solar JAM66D46-735/LB](https://comparepv.com/compare/ja-solar-jam66d46-740-lb/ja-solar-jam66d46-735-lb) - The same specification on paper - [JA Solar JAM66D46-740/LB vs JA Solar JAM66D46-730/LB](https://comparepv.com/compare/ja-solar-jam66d46-740-lb/ja-solar-jam66d46-730-lb) - 3 differences, the largest is module efficiency - [JA Solar JAM66D46-740/LB vs JA Solar JAM66D46-725/LB](https://comparepv.com/compare/ja-solar-jam66d46-740-lb/ja-solar-jam66d46-725-lb) - 3 differences, the largest is module efficiency --- Source: https://comparepv.com/compare/ja-solar-jam54d41-445-lr/ja-solar-jam66d46-740-lb Not in this file, on the page: the thirty-year yield curve year by year at a cell temperature you pick and a written summary generated on request.