--- title: "JA Solar JAM72S42-630/LR vs JA Solar JAM72S42-645/LR - Solar Panel Comparison | ComparePV" description: "Compare JA Solar JAM72S42-630/LR vs JA Solar JAM72S42-645/LR 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-jam72s42-630-lr/ja-solar-jam72s42-645-lr" updated: 2026-09-11 --- # JA Solar JAM72S42-630/LR vs JA Solar JAM72S42-645/LR 645/LR leads on the differences that matter The largest is module efficiency: 0.60 pp more efficient. 16 of 19 comparable parameters are identical. ## The two panels | Attribute | A | B | | --- | --- | --- | | Panel | [JA Solar JAM72S42-630/LR](https://comparepv.com/panel/ja-solar-jam72s42-630-lr) | [JA Solar JAM72S42-645/LR](https://comparepv.com/panel/ja-solar-jam72s42-645-lr) | | Manufacturer | JA Solar | JA Solar | | Power | 630 Wp | 645 Wp | | Efficiency | 22.50 % | 23.10 % | | Technology | TOPCon | TOPCon | ## Where they differ Ranked by how much the difference matters, not by datasheet order. | Parameter | 630/LR | 645/LR | Difference | | --- | --- | --- | --- | | Module efficiency | 22.50 % | 23.10 % | +0.60 pp for 645/LR | | Power density | 225.4 Wp/m² | 230.7 Wp/m² | +5.4 Wp/m² for 645/LR | | Rated power | 630 Wp | 645 Wp | +15 W for 645/LR | ## Every compared parameter | Parameter | 630/LR | 645/LR | | --- | --- | --- | | Rated power | 630 Wp | 645 Wp | | Module efficiency | 22.50 % | 23.10 % | | Power density | 225.4 Wp/m² | 230.7 Wp/m² | | Open-circuit voltage | 52.47 V | 53.07 V | | Voltage at max power | 43.90 V | 44.49 V | | Short-circuit current | 15.21 A | 15.36 A | | Current at max power | 14.35 A | 14.50 A | | Temperature coefficient | -0.290 %/°C | -0.290 %/°C | | Dimensions | 2465x1134x30 mm | 2465x1134x30 mm | | Module area | 2.795 m² | 2.795 m² | | Weight | 29.6 kg | 29.6 kg | | Weight per kWp | 47.0 kg/kWp | 45.9 kg/kWp | | Product warranty | 12 yrs | 12 yrs | | Performance warranty | 25 yrs | 25 yrs | | Annual degradation | 0.40 %/yr | 0.40 %/yr | | Cell technology | TOPCon | TOPCon | | Cell type | Monocrystalline | Monocrystalline | | Cell count | 144 | 144 | | Bifacial | No | No | ## 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, 630/LR:** 21,138 kWh - **Cumulative output, 645/LR:** 21,641 kWh - **Gap:** 503 kWh ## Output when hot | Condition | Cell temperature | 630/LR | 645/LR | Retained | | --- | --- | --- | --- | --- | | Standard test conditions | 25 °C | 630 W | 645 W | 100.0% of rated power | | Cool, bright day | 40 °C | 603 W | 617 W | 95.7% of rated power | | Typical summer roof | 55 °C | 575 W | 589 W | 91.3% of rated power | | Hot roof | 70 °C | 548 W | 561 W | 87.0% of rated power | ## Against the whole database | Measure | 630/LR | 645/LR | Out of | Note | | --- | --- | --- | --- | --- | | Efficiency | #4,222 | #1,570 | 14,005 | 645/LR leads by 2,652 places | | Power density | #3,907 | #1,654 | 14,005 | 645/LR leads by 2,253 places | | Heat behaviour | #2,165 | #2,165 | 14,005 | Tied - the same position in the database | | Weight | #1,445 | #910 | 14,005 | 645/LR leads by 535 places | | Warranty | #9,798 | #9,798 | 14,005 | Tied - the same position in the database | | Overall | #3,657 | #2,495 | 14,005 | 645/LR leads by 1,162 places | ## Questions ### Which panel is better: JA Solar JAM72S42-630/LR or JA Solar JAM72S42-645/LR? According to our database: **JA Solar JAM72S42-645/LR** 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 JAM72S42-630/LR and JA Solar JAM72S42-645/LR? **JA Solar JAM72S42-630/LR** has a module efficiency of **22.50%**, while **JA Solar JAM72S42-645/LR** is **23.10%**. Higher efficiency means more electricity from the same roof area - useful when space is limited. ### What cell technology does JA Solar JAM72S42-630/LR use vs JA Solar JAM72S42-645/LR? **JA Solar JAM72S42-630/LR** uses **TOPCon** cells; **JA Solar JAM72S42-645/LR** 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 JAM72S42-630/LR and JA Solar JAM72S42-645/LR? **JA Solar JAM72S42-630/LR** has a **25 years** power warranty; **JA Solar JAM72S42-645/LR** 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. ## Related comparisons - [JA Solar JAM72S42-630/LR vs JA Solar JAM72S42-650/LR](https://comparepv.com/compare/ja-solar-jam72s42-630-lr/ja-solar-jam72s42-650-lr) - 3 differences, the largest is module efficiency - [JA Solar JAM72S42-630/LR vs JA Solar JAM72S42-640/LR](https://comparepv.com/compare/ja-solar-jam72s42-630-lr/ja-solar-jam72s42-640-lr) - 3 differences, the largest is module efficiency - [JA Solar JAM72S42-630/LR vs JA Solar JAM72S42-635/LR](https://comparepv.com/compare/ja-solar-jam72s42-630-lr/ja-solar-jam72s42-635-lr) - One difference: module efficiency - [JA Solar JAM72S42-630/LR vs JA Solar JAM72S42-625/LR](https://comparepv.com/compare/ja-solar-jam72s42-630-lr/ja-solar-jam72s42-625-lr) - The same specification on paper - [JA Solar JAM72S42-630/LR vs JA Solar JAM72S40-605/LR](https://comparepv.com/compare/ja-solar-jam72s42-630-lr/ja-solar-jam72s40-605-lr) - 9 differences, the largest is weight - [JA Solar JAM72S42-630/LR vs JA Solar JAM72S40-600/LR](https://comparepv.com/compare/ja-solar-jam72s42-630-lr/ja-solar-jam72s40-600-lr) - 8 differences, the largest is rated power --- Source: https://comparepv.com/compare/ja-solar-jam72s42-630-lr/ja-solar-jam72s42-645-lr 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.