--- title: "JA Solar JAM54D41-450/LR vs JA Solar JAM66D45-625/LB - Solar Panel Comparison | ComparePV" description: "Compare JA Solar JAM54D41-450/LR vs JA Solar JAM66D45-625/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-jam54d41-450-lr/ja-solar-jam66d45-625-lb" updated: 2026-09-11 --- # JA Solar JAM54D41-450/LR vs JA Solar JAM66D45-625/LB 14 differences, and they point both ways The largest is rated power: 175 W more power. 5 of 19 comparable parameters are identical. ## The two panels | Attribute | A | B | | --- | --- | --- | | Panel | [JA Solar JAM54D41-450/LR](https://comparepv.com/panel/ja-solar-jam54d41-450-lr) | [JA Solar JAM66D45-625/LB](https://comparepv.com/panel/ja-solar-jam66d45-625-lb) | | Manufacturer | JA Solar | JA Solar | | Power | 450 Wp | 625 Wp | | Efficiency | 22.50 % | 23.10 % | | Technology | TOPCon | TOPCon | ## Where they differ Ranked by how much the difference matters, not by datasheet order. | Parameter | JAM54D41-450/LR | JAM66D45-625/LB | Difference | | --- | --- | --- | --- | | Rated power | 450 Wp | 625 Wp | +175 W for JAM66D45-625/LB | | Module efficiency | 22.50 % | 23.10 % | +0.60 pp for JAM66D45-625/LB | | Weight | 22.0 kg | 33.1 kg | -11.1 kg for JAM54D41-450/LR | | Product warranty | 15 yrs | 12 yrs | +3 yrs for JAM54D41-450/LR | | Power density | 225.2 Wp/m² | 231.4 Wp/m² | +6.2 Wp/m² for JAM66D45-625/LB | | Open-circuit voltage | 40.30 V | 48.70 V | 8.40 V apart | | Module area | 1.998 m² | 2.701 m² | 0.703 m² apart | | Short-circuit current | 14.41 A | 16.15 A | 1.74 A apart | | Weight per kWp | 48.9 kg/kWp | 53.0 kg/kWp | -4.1 kg/kWp for JAM54D41-450/LR | | Voltage at max power | 32.99 V | 40.45 V | 7.46 V apart | | Cell count | 108 | 132 | 24 cells apart | | Current at max power | 13.64 A | 15.45 A | 1.81 A apart | | Bifacial | No | Yes | No vs Yes | | Dimensions | 1762x1134x30 mm | 2382x1134x30 mm | 1762x1134x30 mm vs 2382x1134x30 mm | ## Every compared parameter | Parameter | JAM54D41-450/LR | JAM66D45-625/LB | | --- | --- | --- | | Rated power | 450 Wp | 625 Wp | | Module efficiency | 22.50 % | 23.10 % | | Power density | 225.2 Wp/m² | 231.4 Wp/m² | | Open-circuit voltage | 40.30 V | 48.70 V | | Voltage at max power | 32.99 V | 40.45 V | | Short-circuit current | 14.41 A | 16.15 A | | Current at max power | 13.64 A | 15.45 A | | Temperature coefficient | -0.290 %/°C | -0.290 %/°C | | Dimensions | 1762x1134x30 mm | 2382x1134x30 mm | | Module area | 1.998 m² | 2.701 m² | | Weight | 22.0 kg | 33.1 kg | | Weight per kWp | 48.9 kg/kWp | 53.0 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, JAM54D41-450/LR:** 15,098 kWh - **Cumulative output, JAM66D45-625/LB:** 20,970 kWh - **Gap:** 5,872 kWh ## Output when hot | Condition | Cell temperature | JAM54D41-450/LR | JAM66D45-625/LB | Retained | | --- | --- | --- | --- | --- | | Standard test conditions | 25 °C | 450 W | 625 W | 100.0% of rated power | | Cool, bright day | 40 °C | 430 W | 598 W | 95.7% of rated power | | Typical summer roof | 55 °C | 411 W | 571 W | 91.3% of rated power | | Hot roof | 70 °C | 391 W | 543 W | 87.0% of rated power | ## Against the whole database | Measure | JAM54D41-450/LR | JAM66D45-625/LB | Out of | Note | | --- | --- | --- | --- | --- | | Efficiency | #4,222 | #1,570 | 14,005 | JAM66D45-625/LB leads by 2,652 places | | Power density | #4,225 | #1,513 | 14,005 | JAM66D45-625/LB leads by 2,712 places | | Heat behaviour | #2,165 | #2,165 | 14,005 | Tied - the same position in the database | | Weight | #2,563 | #6,680 | 14,005 | JAM54D41-450/LR leads by 4,117 places | | Warranty | #21 | #21 | 14,005 | Tied - the same position in the database | | Overall | #8,397 | #2,270 | 14,005 | JAM66D45-625/LB leads by 6,127 places | ## Questions ### Which panel is better: JA Solar JAM54D41-450/LR or JA Solar JAM66D45-625/LB? According to our database: **JA Solar JAM66D45-625/LB** has higher module efficiency (**23.10%** vs **22.50%**). See the full spec comparison and 30-year energy simulation above for a complete picture. ### What is the efficiency of JA Solar JAM54D41-450/LR and JA Solar JAM66D45-625/LB? **JA Solar JAM54D41-450/LR** has a module efficiency of **22.50%**, while **JA Solar JAM66D45-625/LB** is **23.10%**. Higher efficiency means more electricity from the same roof area - useful when space is limited. ### What cell technology does JA Solar JAM54D41-450/LR use vs JA Solar JAM66D45-625/LB? **JA Solar JAM54D41-450/LR** uses **TOPCon** cells; **JA Solar JAM66D45-625/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 JAM54D41-450/LR and JA Solar JAM66D45-625/LB? **JA Solar JAM54D41-450/LR** has a **30 years** power warranty; **JA Solar JAM66D45-625/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 JAM54D41-450/LR and JA Solar JAM66D45-625/LB bifacial panels? **JA Solar JAM66D45-625/LB** is bifacial (captures light from both faces); **JA Solar JAM54D41-450/LR** is monofacial. Bifacial panels work best on ground mounts or raised structures with a light-coloured surface underneath. ## Related comparisons - [JA Solar JAM54D41-450/LR vs JA Solar JAM54D41-455/LR](https://comparepv.com/compare/ja-solar-jam54d41-450-lr/ja-solar-jam54d41-455-lr) - One difference: module efficiency - [JA Solar JAM54D41-450/LR vs JA Solar JAM54D41-445/LR](https://comparepv.com/compare/ja-solar-jam54d41-450-lr/ja-solar-jam54d41-445-lr) - 2 differences, the largest is module efficiency - [JA Solar JAM54D41-450/LR vs JA Solar JAM54D41-440/LR](https://comparepv.com/compare/ja-solar-jam54d41-450-lr/ja-solar-jam54d41-440-lr) - 4 differences, the largest is module efficiency - [JA Solar JAM66D45-625/LB vs JA Solar JAM66D45-630/LB](https://comparepv.com/compare/ja-solar-jam66d45-625-lb/ja-solar-jam66d45-630-lb) - One difference: module efficiency - [JA Solar JAM66D45-625/LB vs JA Solar JAM66D45-620/LB](https://comparepv.com/compare/ja-solar-jam66d45-625-lb/ja-solar-jam66d45-620-lb) - The same specification on paper - [JA Solar JAM66D45-625/LB vs JA Solar JAM66D45-615/LB](https://comparepv.com/compare/ja-solar-jam66d45-625-lb/ja-solar-jam66d45-615-lb) - 3 differences, the largest is module efficiency --- Source: https://comparepv.com/compare/ja-solar-jam54d41-450-lr/ja-solar-jam66d45-625-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.