--- title: "JA Solar JAM66D46-735/LB vs JA Solar JAM72S20-455/MR - Solar Panel Comparison | ComparePV" description: "Compare JA Solar JAM66D46-735/LB vs JA Solar JAM72S20-455/MR 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-jam66d46-735-lb/ja-solar-jam72s20-455-mr-1" updated: 2026-09-11 --- # JA Solar JAM66D46-735/LB vs JA Solar JAM72S20-455/MR JAM66D46-735/LB leads on the differences that matter The largest is module efficiency: 3.20 pp more efficient. 5 of 19 comparable parameters are identical. ## The two panels | Attribute | A | B | | --- | --- | --- | | Panel | [JA Solar JAM66D46-735/LB](https://comparepv.com/panel/ja-solar-jam66d46-735-lb) | [JA Solar JAM72S20-455/MR](https://comparepv.com/panel/ja-solar-jam72s20-455-mr-1) | | Manufacturer | JA Solar | JA Solar | | Power | 735 Wp | 455 Wp | | Efficiency | 23.70 % | 20.50 % | | Technology | TOPCon | PERC | ## Where they differ Ranked by how much the difference matters, not by datasheet order. | Parameter | JAM66D46-735/LB | JAM72S20-455/MR | Difference | | --- | --- | --- | --- | | Module efficiency | 23.70 % | 20.50 % | +3.20 pp for JAM66D46-735/LB | | Temperature coefficient | -0.290 %/°C | -0.350 %/°C | +0.060 %/°C for JAM66D46-735/LB | | Rated power | 735 Wp | 455 Wp | +280 W for JAM66D46-735/LB | | Power density | 236.6 Wp/m² | 204.8 Wp/m² | +31.8 Wp/m² for JAM66D46-735/LB | | Performance warranty | 30 yrs | 25 yrs | +5 yrs for JAM66D46-735/LB | | Annual degradation | 0.40 %/yr | 0.55 %/yr | -0.15 %/yr for JAM66D46-735/LB | | Weight | 38.2 kg | 24.5 kg | -13.7 kg for JAM72S20-455/MR | | Short-circuit current | 18.70 A | 11.41 A | 7.29 A apart | | Module area | 3.106 m² | 2.222 m² | 0.885 m² apart | | Cell technology | TOPCon | PERC | TOPCon vs PERC | | Current at max power | 17.60 A | 10.88 A | 6.72 A apart | | Cell count | 132 | 144 | 12 cells apart | | Bifacial | Yes | No | Yes vs No | | Dimensions | 2384x1303x33 mm | 2112x1052x35 mm | 2384x1303x33 mm vs 2112x1052x35 mm | ## Every compared parameter | Parameter | JAM66D46-735/LB | JAM72S20-455/MR | | --- | --- | --- | | Rated power | 735 Wp | 455 Wp | | Module efficiency | 23.70 % | 20.50 % | | Power density | 236.6 Wp/m² | 204.8 Wp/m² | | Open-circuit voltage | 49.60 V | 49.85 V | | Voltage at max power | 41.77 V | 41.82 V | | Short-circuit current | 18.70 A | 11.41 A | | Current at max power | 17.60 A | 10.88 A | | Temperature coefficient | -0.290 %/°C | -0.350 %/°C | | Dimensions | 2384x1303x33 mm | 2112x1052x35 mm | | Module area | 3.106 m² | 2.222 m² | | Weight | 38.2 kg | 24.5 kg | | Weight per kWp | 52.0 kg/kWp | 53.8 kg/kWp | | Product warranty | 12 yrs | 12 yrs | | Performance warranty | 30 yrs | 25 yrs | | Annual degradation | 0.40 %/yr | 0.55 %/yr | | Cell technology | TOPCon | PERC | | Cell type | Monocrystalline | Monocrystalline | | Cell count | 132 | 144 | | Bifacial | Yes | No | ## Thirty-year yield Each panel's own declared degradation curve, at 1,200 kWh/kWp a year - **Cumulative output, JAM66D46-735/LB:** 24,661 kWh - **Cumulative output, JAM72S20-455/MR:** 14,746 kWh - **Gap:** 9,915 kWh ## Output when hot | Condition | Cell temperature | JAM66D46-735/LB | JAM72S20-455/MR | Retained | | --- | --- | --- | --- | --- | | Standard test conditions | 25 °C | 735 W | 455 W | 100.0% of rated power | | Cool, bright day | 40 °C | 703 W | 431 W | 94.8% of rated power | | Typical summer roof | 55 °C | 671 W | 407 W | 89.5% of rated power | | Hot roof | 70 °C | 639 W | 383 W | 84.2% of rated power | ## Against the whole database | Measure | JAM66D46-735/LB | JAM72S20-455/MR | Out of | Note | | --- | --- | --- | --- | --- | | Efficiency | #517 | #11,308 | 14,005 | JAM66D46-735/LB leads by 10,791 places | | Power density | #582 | #11,472 | 14,005 | JAM66D46-735/LB leads by 10,890 places | | Heat behaviour | #2,165 | #10,419 | 14,005 | JAM66D46-735/LB leads by 8,254 places | | Weight | #5,413 | #7,897 | 14,005 | JAM66D46-735/LB leads by 2,484 places | | Warranty | #21 | #9,798 | 14,005 | JAM66D46-735/LB leads by 9,777 places | | Overall | #233 | #11,208 | 14,005 | JAM66D46-735/LB leads by 10,975 places | ## Questions ### Which panel is better: JA Solar JAM66D46-735/LB or JA Solar JAM72S20-455/MR? According to our database: **JA Solar JAM66D46-735/LB** has higher module efficiency (**23.70%** vs **20.50%**); **JA Solar JAM66D46-735/LB** tolerates heat better (temp coeff **-0.290%/°C** vs **-0.350%/°C**). See the full spec comparison and 30-year energy simulation above for a complete picture. ### What is the efficiency of JA Solar JAM66D46-735/LB and JA Solar JAM72S20-455/MR? **JA Solar JAM66D46-735/LB** has a module efficiency of **23.70%**, while **JA Solar JAM72S20-455/MR** is **20.50%**. Higher efficiency means more electricity from the same roof area - useful when space is limited. ### What cell technology does JA Solar JAM66D46-735/LB use vs JA Solar JAM72S20-455/MR? **JA Solar JAM66D46-735/LB** uses **TOPCon** cells; **JA Solar JAM72S20-455/MR** uses **PERC**. 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 JAM66D46-735/LB and JA Solar JAM72S20-455/MR? **JA Solar JAM66D46-735/LB** has a **30 years** power warranty; **JA Solar JAM72S20-455/MR** has a **25 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 JAM66D46-735/LB and JA Solar JAM72S20-455/MR bifacial panels? **JA Solar JAM66D46-735/LB** is bifacial (captures light from both faces); **JA Solar JAM72S20-455/MR** is monofacial. Bifacial panels work best on ground mounts or raised structures with a light-coloured surface underneath. ## Related comparisons - [JA Solar JAM66D46-735/LB vs JA Solar JAM66D46-740/LB](https://comparepv.com/compare/ja-solar-jam66d46-735-lb/ja-solar-jam66d46-740-lb) - The same specification on paper - [JA Solar JAM66D46-735/LB vs JA Solar JAM66D46-730/LB](https://comparepv.com/compare/ja-solar-jam66d46-735-lb/ja-solar-jam66d46-730-lb) - One difference: module efficiency - [JA Solar JAM66D46-735/LB vs JA Solar JAM66D46-725/LB](https://comparepv.com/compare/ja-solar-jam66d46-735-lb/ja-solar-jam66d46-725-lb) - 3 differences, the largest is module efficiency - [JA Solar JAM66D46-735/LB vs JA Solar JAM66D46-720/LB](https://comparepv.com/compare/ja-solar-jam66d46-735-lb/ja-solar-jam66d46-720-lb) - 3 differences, the largest is module efficiency - [JA Solar JAM66D46-735/LB vs JA Solar JAM66D46-715/LB](https://comparepv.com/compare/ja-solar-jam66d46-735-lb/ja-solar-jam66d46-715-lb) - 3 differences, the largest is module efficiency - [JA Solar JAM66D46-735/LB vs JA Solar JAM66D46-710/LB](https://comparepv.com/compare/ja-solar-jam66d46-735-lb/ja-solar-jam66d46-710-lb) - 5 differences, the largest is module efficiency --- Source: https://comparepv.com/compare/ja-solar-jam66d46-735-lb/ja-solar-jam72s20-455-mr-1 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.