--- title: "JA Solar JAM66D45-610/LB vs JA Solar JAM72D40-600/MB - Solar Panel Comparison | ComparePV" description: "Compare JA Solar JAM66D45-610/LB vs JA Solar JAM72D40-600/MB 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-jam66d45-610-lb/ja-solar-jam72d40-600-mb" image: "https://comparepv.com/og/compare/panels/ja-solar-jam66d45-610-lb/ja-solar-jam72d40-600-mb.png" updated: 2026-09-11 --- # JA Solar JAM66D45-610/LB vs JA Solar JAM72D40-600/MB JAM72D40-600/MB leads on the differences that matter The largest is module efficiency: 0.60 pp more efficient. 8 of 19 comparable parameters are identical. ## The two panels | Attribute | A | B | | --- | --- | --- | | Panel | [JA Solar JAM66D45-610/LB](https://comparepv.com/panel/ja-solar-jam66d45-610-lb) | [JA Solar JAM72D40-600/MB](https://comparepv.com/panel/ja-solar-jam72d40-600-mb) | | Manufacturer | JA Solar | JA Solar | | Power | 610 Wp | 600 Wp | | Efficiency | 22.60 % | 23.20 % | | Technology | TOPCon | TOPCon | ## Where they differ Ranked by how much the difference matters, not by datasheet order. | Parameter | JAM66D45-610/LB | JAM72D40-600/MB | Difference | | --- | --- | --- | --- | | Module efficiency | 22.60 % | 23.20 % | +0.60 pp for JAM72D40-600/MB | | Power density | 225.8 Wp/m² | 232.3 Wp/m² | +6.4 Wp/m² for JAM72D40-600/MB | | Open-circuit voltage | 48.10 V | 52.79 V | 4.69 V apart | | Short-circuit current | 16.05 A | 14.04 A | 2.01 A apart | | Module area | 2.701 m² | 2.583 m² | 0.118 m² apart | | Rated power | 610 Wp | 600 Wp | +10 W for JAM66D45-610/LB | | Voltage at max power | 39.77 V | 44.85 V | 5.08 V apart | | Cell count | 132 | 144 | 12 cells apart | | Current at max power | 15.34 A | 13.38 A | 1.96 A apart | | Weight | 33.1 kg | 31.8 kg | -1.3 kg for JAM72D40-600/MB | | Dimensions | 2382x1134x30 mm | 2278x1134x30 mm | 2382x1134x30 mm vs 2278x1134x30 mm | ## Every compared parameter | Parameter | JAM66D45-610/LB | JAM72D40-600/MB | | --- | --- | --- | | Rated power | 610 Wp | 600 Wp | | Module efficiency | 22.60 % | 23.20 % | | Power density | 225.8 Wp/m² | 232.3 Wp/m² | | Open-circuit voltage | 48.10 V | 52.79 V | | Voltage at max power | 39.77 V | 44.85 V | | Short-circuit current | 16.05 A | 14.04 A | | Current at max power | 15.34 A | 13.38 A | | Temperature coefficient | -0.290 %/°C | -0.290 %/°C | | Dimensions | 2382x1134x30 mm | 2278x1134x30 mm | | Module area | 2.701 m² | 2.583 m² | | Weight | 33.1 kg | 31.8 kg | | Weight per kWp | 54.3 kg/kWp | 53.0 kg/kWp | | Product warranty | 12 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 | 132 | 144 | | Bifacial | Yes | 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, JAM66D45-610/LB:** 20,467 kWh - **Cumulative output, JAM72D40-600/MB:** 20,131 kWh - **Gap:** 336 kWh ## Output when hot | Condition | Cell temperature | JAM66D45-610/LB | JAM72D40-600/MB | Retained | | --- | --- | --- | --- | --- | | Standard test conditions | 25 °C | 610 W | 600 W | 100.0% of rated power | | Cool, bright day | 40 °C | 583 W | 574 W | 95.7% of rated power | | Typical summer roof | 55 °C | 557 W | 548 W | 91.3% of rated power | | Hot roof | 70 °C | 530 W | 522 W | 87.0% of rated power | ## Against the whole database | Measure | JAM66D45-610/LB | JAM72D40-600/MB | Out of | Note | | --- | --- | --- | --- | --- | | Efficiency | #3,785 | #1,390 | 14,269 | JAM72D40-600/MB leads by 2,395 places | | Power density | #3,857 | #1,336 | 14,269 | JAM72D40-600/MB leads by 2,521 places | | Heat behaviour | #2,260 | #2,260 | 14,269 | Tied - the same position in the database | | Weight | #8,656 | #6,832 | 14,269 | JAM72D40-600/MB leads by 1,824 places | | Warranty | #31 | #31 | 14,269 | Tied - the same position in the database | | Overall | #3,380 | #3,054 | 14,269 | JAM72D40-600/MB leads by 326 places | ## Questions ### Which panel is better: JA Solar JAM66D45-610/LB or JA Solar JAM72D40-600/MB? According to our database: **JA Solar JAM72D40-600/MB** has higher module efficiency (**23.20%** vs **22.60%**). See the full spec comparison and 30-year energy simulation above for a complete picture. ### What is the efficiency of JA Solar JAM66D45-610/LB and JA Solar JAM72D40-600/MB? **JA Solar JAM66D45-610/LB** has a module efficiency of **22.60%**, while **JA Solar JAM72D40-600/MB** is **23.20%**. Higher efficiency means more electricity from the same roof area - useful when space is limited. ### What cell technology does JA Solar JAM66D45-610/LB use vs JA Solar JAM72D40-600/MB? **JA Solar JAM66D45-610/LB** uses **TOPCon** cells; **JA Solar JAM72D40-600/MB** 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 JAM66D45-610/LB and JA Solar JAM72D40-600/MB? **JA Solar JAM66D45-610/LB** has a **30 years** power warranty; **JA Solar JAM72D40-600/MB** 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 JAM66D45-610/LB and JA Solar JAM72D40-600/MB bifacial panels? Both **JA Solar JAM66D45-610/LB** and **JA Solar JAM72D40-600/MB** are bifacial - they capture reflected light from the ground, which can add 5**-15%** more annual energy on ground-mount or elevated rooftop installations with a light surface beneath. ## Related comparisons - [JA Solar JAM66D45-610/LB vs JA Solar JAM66D45-630/LB](https://comparepv.com/compare/ja-solar-jam66d45-610-lb/ja-solar-jam66d45-630-lb) - 3 differences, the largest is module efficiency - [JA Solar JAM66D45-610/LB vs JA Solar JAM66D45-625/LB](https://comparepv.com/compare/ja-solar-jam66d45-610-lb/ja-solar-jam66d45-625-lb) - 3 differences, the largest is module efficiency - [JA Solar JAM66D45-610/LB vs JA Solar JAM66D45-620/LB](https://comparepv.com/compare/ja-solar-jam66d45-610-lb/ja-solar-jam66d45-620-lb) - 3 differences, the largest is module efficiency - [JA Solar JAM66D45-610/LB vs JA Solar JAM66D45-615/LB](https://comparepv.com/compare/ja-solar-jam66d45-610-lb/ja-solar-jam66d45-615-lb) - One difference: module efficiency - [JA Solar JAM66D45-610/LB vs JA Solar JAM66D45-605/LB](https://comparepv.com/compare/ja-solar-jam66d45-610-lb/ja-solar-jam66d45-605-lb) - One difference: module efficiency - [JA Solar JAM66D45-610/LB vs JA Solar JAM72D30-580/LB/1500V](https://comparepv.com/compare/ja-solar-jam66d45-610-lb/ja-solar-jam72d30-580-lb-1500v) - 13 differences, the largest is temperature coefficient --- Source: https://comparepv.com/compare/ja-solar-jam66d45-610-lb/ja-solar-jam72d40-600-mb 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.