--- title: "JA Solar JAM72S30-540/MR/1500V vs JA Solar JAM78D30-580/MB/1500V - Solar Panel Comparison | ComparePV" description: "Compare JA Solar JAM72S30-540/MR/1500V vs JA Solar JAM78D30-580/MB/1500V side by side: what actually differs, output when it is hot, thirty-year production, and the full specification." source: "https://comparepv.com/compare/shanghai-ja-solar-technology-co-ltd-jam72s30-540-mr-1500v/shanghai-ja-solar-technology-co-ltd-jam78d30-580-mb-1500v" image: "https://comparepv.com/og/compare/panels/shanghai-ja-solar-technology-co-ltd-jam72s30-540-mr-1500v/shanghai-ja-solar-technology-co-ltd-jam78d30-580-mb-1500v.png" updated: 2026-09-11 --- # JA Solar JAM72S30-540/MR/1500V vs JA Solar JAM78D30-580/MB/1500V 12 differences, and they point both ways The largest is rated power: 40 W more power. 7 of 19 comparable parameters are identical. ## The two panels | Attribute | A | B | | --- | --- | --- | | Panel | [JA Solar JAM72S30-540/MR/1500V](https://comparepv.com/panel/shanghai-ja-solar-technology-co-ltd-jam72s30-540-mr-1500v) | [JA Solar JAM78D30-580/MB/1500V](https://comparepv.com/panel/shanghai-ja-solar-technology-co-ltd-jam78d30-580-mb-1500v) | | Manufacturer | JA Solar | JA Solar | | Power | 540 Wp | 580 Wp | | Efficiency | 20.90 % | 20.70 % | | Technology | PERC | PERC | ## Where they differ Ranked by how much the difference matters, not by datasheet order. | Parameter | JAM72S30-540/MR/1500V | JAM78D30-580/MB/1500V | Difference | | --- | --- | --- | --- | | Rated power | 540 Wp | 580 Wp | +40 W for JAM78D30-580/MB/1500V | | Performance warranty | 25 yrs | 30 yrs | +5 yrs for JAM78D30-580/MB/1500V | | Weight | 27.3 kg | 33.4 kg | -6.1 kg for JAM72S30-540/MR/1500V | | Weight per kWp | 50.6 kg/kWp | 57.6 kg/kWp | -7.0 kg/kWp for JAM72S30-540/MR/1500V | | Annual degradation | 0.55 %/yr | 0.45 %/yr | -0.10 %/yr for JAM78D30-580/MB/1500V | | Module area | 2.583 m² | 2.795 m² | 0.212 m² apart | | Open-circuit voltage | 49.60 V | 53.11 V | 3.51 V apart | | Module efficiency | 20.90 % | 20.70 % | +0.20 pp for JAM72S30-540/MR/1500V | | Cell count | 144 | 156 | 12 cells apart | | Bifacial | No | Yes | No vs Yes | | Voltage at max power | 41.64 V | 44.35 V | 2.71 V apart | | Dimensions | 2278x1134x30 mm | 2465x1134x35 mm | 2278x1134x30 mm vs 2465x1134x35 mm | ## Every compared parameter | Parameter | JAM72S30-540/MR/1500V | JAM78D30-580/MB/1500V | | --- | --- | --- | | Rated power | 540 Wp | 580 Wp | | Module efficiency | 20.90 % | 20.70 % | | Power density | 209.0 Wp/m² | 207.5 Wp/m² | | Open-circuit voltage | 49.60 V | 53.11 V | | Voltage at max power | 41.64 V | 44.35 V | | Short-circuit current | 13.86 A | 13.84 A | | Current at max power | 12.97 A | 13.08 A | | Temperature coefficient | -0.350 %/°C | -0.350 %/°C | | Dimensions | 2278x1134x30 mm | 2465x1134x35 mm | | Module area | 2.583 m² | 2.795 m² | | Weight | 27.3 kg | 33.4 kg | | Weight per kWp | 50.6 kg/kWp | 57.6 kg/kWp | | Product warranty | 12 yrs | 12 yrs | | Performance warranty | 25 yrs | 30 yrs | | Annual degradation | 0.55 %/yr | 0.45 %/yr | | Cell technology | PERC | PERC | | Cell type | Monocrystalline | Monocrystalline | | Cell count | 144 | 156 | | 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 (-0.350 %/°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, JAM72S30-540/MR/1500V:** 17,501 kWh - **Cumulative output, JAM78D30-580/MB/1500V:** 19,100 kWh - **Gap:** 1,599 kWh ## Output when hot | Condition | Cell temperature | JAM72S30-540/MR/1500V | JAM78D30-580/MB/1500V | Retained | | --- | --- | --- | --- | --- | | Standard test conditions | 25 °C | 540 W | 580 W | 100.0% of rated power | | Cool, bright day | 40 °C | 512 W | 550 W | 94.8% of rated power | | Typical summer roof | 55 °C | 483 W | 519 W | 89.5% of rated power | | Hot roof | 70 °C | 455 W | 489 W | 84.2% of rated power | ## Against the whole database | Measure | JAM72S30-540/MR/1500V | JAM78D30-580/MB/1500V | Out of | Note | | --- | --- | --- | --- | --- | | Efficiency | #10,148 | #10,842 | 14,129 | JAM72S30-540/MR/1500V leads by 694 places | | Power density | #10,176 | #10,672 | 14,129 | JAM72S30-540/MR/1500V leads by 496 places | | Heat behaviour | #10,489 | #10,489 | 14,129 | Tied - the same position in the database | | Weight | #3,965 | #11,388 | 14,129 | JAM72S30-540/MR/1500V leads by 7,423 places | | Warranty | #9,912 | #21 | 14,129 | JAM78D30-580/MB/1500V leads by 9,891 places | | Overall | #8,957 | #6,690 | 14,129 | JAM78D30-580/MB/1500V leads by 2,267 places | ## Questions ### Which panel is better: JA Solar JAM72S30-540/MR/1500V or JA Solar JAM78D30-580/MB/1500V? According to our database: **JA Solar JAM72S30-540/MR/1500V** has higher module efficiency (**20.90%** vs **20.70%**). See the full spec comparison and 30-year energy simulation above for a complete picture. ### What is the efficiency of JA Solar JAM72S30-540/MR/1500V and JA Solar JAM78D30-580/MB/1500V? **JA Solar JAM72S30-540/MR/1500V** has a module efficiency of **20.90%**, while **JA Solar JAM78D30-580/MB/1500V** is **20.70%**. Higher efficiency means more electricity from the same roof area - useful when space is limited. ### What cell technology does JA Solar JAM72S30-540/MR/1500V use vs JA Solar JAM78D30-580/MB/1500V? **JA Solar JAM72S30-540/MR/1500V** uses **PERC** cells; **JA Solar JAM78D30-580/MB/1500V** 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 JAM72S30-540/MR/1500V and JA Solar JAM78D30-580/MB/1500V? **JA Solar JAM72S30-540/MR/1500V** has a **25 years** power warranty; **JA Solar JAM78D30-580/MB/1500V** 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 JAM72S30-540/MR/1500V and JA Solar JAM78D30-580/MB/1500V bifacial panels? **JA Solar JAM78D30-580/MB/1500V** is bifacial (captures light from both faces); **JA Solar JAM72S30-540/MR/1500V** is monofacial. Bifacial panels work best on ground mounts or raised structures with a light-coloured surface underneath. ## Related comparisons - [JA Solar JAM72S30-540/MR/1500V vs JA Solar JAM78D30-605/MB/1500V](https://comparepv.com/compare/shanghai-ja-solar-technology-co-ltd-jam72s30-540-mr-1500v/shanghai-ja-solar-technology-co-ltd-jam78d30-605-mb-1500v) - 13 differences, the largest is module efficiency - [JA Solar JAM72S30-540/MR/1500V vs JA Solar JAM78D30-600/MB/1500V](https://comparepv.com/compare/shanghai-ja-solar-technology-co-ltd-jam72s30-540-mr-1500v/shanghai-ja-solar-technology-co-ltd-jam78d30-600-mb-1500v) - 13 differences, the largest is rated power - [JA Solar JAM72S30-540/MR/1500V vs JA Solar JAM78D30-595/MB/1500V](https://comparepv.com/compare/shanghai-ja-solar-technology-co-ltd-jam72s30-540-mr-1500v/shanghai-ja-solar-technology-co-ltd-jam78d30-595-mb-1500v) - 13 differences, the largest is rated power - [JA Solar JAM72S30-540/MR/1500V vs JA Solar JAM78D30-590/MB/1500V](https://comparepv.com/compare/shanghai-ja-solar-technology-co-ltd-jam72s30-540-mr-1500v/shanghai-ja-solar-technology-co-ltd-jam78d30-590-mb-1500v) - 12 differences, the largest is rated power - [JA Solar JAM72S30-540/MR/1500V vs JA Solar JAM78D30-585/MB/1500V](https://comparepv.com/compare/shanghai-ja-solar-technology-co-ltd-jam72s30-540-mr-1500v/shanghai-ja-solar-technology-co-ltd-jam78d30-585-mb-1500v) - 11 differences, the largest is rated power - [JA Solar JAM72S30-540/MR/1500V vs JA Solar JAM72D30-580/LB/1500V](https://comparepv.com/compare/shanghai-ja-solar-technology-co-ltd-jam72s30-540-mr-1500v/ja-solar-jam72d30-580-lb-1500v) - 13 differences, the largest is module efficiency --- Source: https://comparepv.com/compare/shanghai-ja-solar-technology-co-ltd-jam72s30-540-mr-1500v/shanghai-ja-solar-technology-co-ltd-jam78d30-580-mb-1500v 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.