--- title: "JA Solar JAM54S30-420/MR vs JA Solar JAM66D46-720/LB - Solar Panel Comparison | ComparePV" description: "Compare JA Solar JAM54S30-420/MR vs JA Solar JAM66D46-720/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-jam54s30-420-mr/ja-solar-jam66d46-720-lb" updated: 2026-09-11 --- # JA Solar JAM54S30-420/MR vs JA Solar JAM66D46-720/LB JAM66D46-720/LB leads on the differences that matter The largest is module efficiency: 1.70 pp more efficient. 2 of 19 comparable parameters are identical. ## The two panels | Attribute | A | B | | --- | --- | --- | | Panel | [JA Solar JAM54S30-420/MR](https://comparepv.com/panel/ja-solar-jam54s30-420-mr) | [JA Solar JAM66D46-720/LB](https://comparepv.com/panel/ja-solar-jam66d46-720-lb) | | Manufacturer | JA Solar | JA Solar | | Power | 420 Wp | 720 Wp | | Efficiency | 21.50 % | 23.20 % | | Technology | PERC | TOPCon | ## Where they differ Ranked by how much the difference matters, not by datasheet order. | Parameter | JAM54S30-420/MR | JAM66D46-720/LB | Difference | | --- | --- | --- | --- | | Module efficiency | 21.50 % | 23.20 % | +1.70 pp for JAM66D46-720/LB | | Temperature coefficient | -0.350 %/°C | -0.290 %/°C | +0.060 %/°C for JAM66D46-720/LB | | Rated power | 420 Wp | 720 Wp | +300 W for JAM66D46-720/LB | | Power density | 215.1 Wp/m² | 231.8 Wp/m² | +16.7 Wp/m² for JAM66D46-720/LB | | Performance warranty | 25 yrs | 30 yrs | +5 yrs for JAM66D46-720/LB | | Annual degradation | 0.55 %/yr | 0.40 %/yr | -0.15 %/yr for JAM66D46-720/LB | | Weight | 19.5 kg | 38.2 kg | -18.7 kg for JAM54S30-420/MR | | Weight per kWp | 46.4 kg/kWp | 53.1 kg/kWp | -6.6 kg/kWp for JAM54S30-420/MR | | Open-circuit voltage | 37.58 V | 49.00 V | 11.42 V apart | | Short-circuit current | 14.10 A | 18.59 A | 4.49 A apart | | Module area | 1.953 m² | 3.106 m² | 1.154 m² apart | | Cell technology | PERC | TOPCon | PERC vs TOPCon | | Voltage at max power | 31.80 V | 41.19 V | 9.39 V apart | | Current at max power | 13.21 A | 17.48 A | 4.27 A apart | | Cell count | 108 | 132 | 24 cells apart | | Bifacial | No | Yes | No vs Yes | | Dimensions | 1722x1134x30 mm | 2384x1303x33 mm | 1722x1134x30 mm vs 2384x1303x33 mm | ## Every compared parameter | Parameter | JAM54S30-420/MR | JAM66D46-720/LB | | --- | --- | --- | | Rated power | 420 Wp | 720 Wp | | Module efficiency | 21.50 % | 23.20 % | | Power density | 215.1 Wp/m² | 231.8 Wp/m² | | Open-circuit voltage | 37.58 V | 49.00 V | | Voltage at max power | 31.80 V | 41.19 V | | Short-circuit current | 14.10 A | 18.59 A | | Current at max power | 13.21 A | 17.48 A | | Temperature coefficient | -0.350 %/°C | -0.290 %/°C | | Dimensions | 1722x1134x30 mm | 2384x1303x33 mm | | Module area | 1.953 m² | 3.106 m² | | Weight | 19.5 kg | 38.2 kg | | Weight per kWp | 46.4 kg/kWp | 53.1 kg/kWp | | Product warranty | 12 yrs | 12 yrs | | Performance warranty | 25 yrs | 30 yrs | | Annual degradation | 0.55 %/yr | 0.40 %/yr | | Cell technology | PERC | 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 - **Cumulative output, JAM54S30-420/MR:** 13,612 kWh - **Cumulative output, JAM66D46-720/LB:** 24,157 kWh - **Gap:** 10,545 kWh ## Output when hot | Condition | Cell temperature | JAM54S30-420/MR | JAM66D46-720/LB | Retained | | --- | --- | --- | --- | --- | | Standard test conditions | 25 °C | 420 W | 720 W | 100.0% of rated power | | Cool, bright day | 40 °C | 398 W | 689 W | 94.8% of rated power | | Typical summer roof | 55 °C | 376 W | 657 W | 89.5% of rated power | | Hot roof | 70 °C | 354 W | 626 W | 84.2% of rated power | ## Against the whole database | Measure | JAM54S30-420/MR | JAM66D46-720/LB | Out of | Note | | --- | --- | --- | --- | --- | | Efficiency | #7,958 | #1,306 | 14,005 | JAM66D46-720/LB leads by 6,652 places | | Power density | #7,882 | #1,347 | 14,005 | JAM66D46-720/LB leads by 6,535 places | | Heat behaviour | #10,419 | #2,165 | 14,005 | JAM66D46-720/LB leads by 8,254 places | | Weight | #1,155 | #6,810 | 14,005 | JAM54S30-420/MR leads by 5,655 places | | Warranty | #9,798 | #21 | 14,005 | JAM66D46-720/LB leads by 9,777 places | | Overall | #11,103 | #516 | 14,005 | JAM66D46-720/LB leads by 10,587 places | ## Questions ### Which panel is better: JA Solar JAM54S30-420/MR or JA Solar JAM66D46-720/LB? According to our database: **JA Solar JAM66D46-720/LB** has higher module efficiency (**23.20%** vs **21.50%**); **JA Solar JAM66D46-720/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 JAM54S30-420/MR and JA Solar JAM66D46-720/LB? **JA Solar JAM54S30-420/MR** has a module efficiency of **21.50%**, while **JA Solar JAM66D46-720/LB** is **23.20%**. Higher efficiency means more electricity from the same roof area - useful when space is limited. ### What cell technology does JA Solar JAM54S30-420/MR use vs JA Solar JAM66D46-720/LB? **JA Solar JAM54S30-420/MR** uses **PERC** cells; **JA Solar JAM66D46-720/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 JAM54S30-420/MR and JA Solar JAM66D46-720/LB? **JA Solar JAM54S30-420/MR** has a **25 years** power warranty; **JA Solar JAM66D46-720/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 JAM54S30-420/MR and JA Solar JAM66D46-720/LB bifacial panels? **JA Solar JAM66D46-720/LB** is bifacial (captures light from both faces); **JA Solar JAM54S30-420/MR** is monofacial. Bifacial panels work best on ground mounts or raised structures with a light-coloured surface underneath. ## Related comparisons - [JA Solar JAM54S30-420/MR vs JA Solar JAM54S30-425/MR](https://comparepv.com/compare/ja-solar-jam54s30-420-mr/ja-solar-jam54s30-425-mr) - One difference: module efficiency - [JA Solar JAM54S30-420/MR vs JA Solar JAM54S30-415/MR](https://comparepv.com/compare/ja-solar-jam54s30-420-mr/ja-solar-jam54s30-415-mr) - One difference: module efficiency - [JA Solar JAM54S30-420/MR vs JA Solar JAM54S30-410/MR](https://comparepv.com/compare/ja-solar-jam54s30-420-mr/ja-solar-jam54s30-410-mr) - 3 differences, the largest is module efficiency - [JA Solar JAM54S30-420/MR vs JA Solar JAM54S30-405/MR](https://comparepv.com/compare/ja-solar-jam54s30-420-mr/ja-solar-jam54s30-405-mr) - 3 differences, the largest is module efficiency - [JA Solar JAM54S30-420/MR vs JA Solar JAM54S31-405/MR](https://comparepv.com/compare/ja-solar-jam54s30-420-mr/ja-solar-jam54s31-405-mr) - 3 differences, the largest is module efficiency - [JA Solar JAM54S30-420/MR vs JA Solar JAM54S30-400/MR](https://comparepv.com/compare/ja-solar-jam54s30-420-mr/ja-solar-jam54s30-400-mr) - 4 differences, the largest is module efficiency --- Source: https://comparepv.com/compare/ja-solar-jam54s30-420-mr/ja-solar-jam66d46-720-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.