---
title: "JA Solar JAM66D46-720/LB vs Longi Solar LR7-72HVHF-670M - Solar Panel Comparison | ComparePV"
description: "Compare JA Solar JAM66D46-720/LB vs Longi Solar LR7-72HVHF-670M 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-jam66d46-720-lb/longi-lr7-72hvhf-670m"
updated: 2026-09-11
---

# JA Solar JAM66D46-720/LB vs Longi Solar LR7-72HVHF-670M

LR7-72HVHF-670M leads on the differences that matter

The largest is module efficiency: 1.60 pp more efficient. 2 of 19 comparable parameters are identical.


## The two panels


| Attribute | A | B |
| --- | --- | --- |
| Panel | [JA Solar JAM66D46-720/LB](https://comparepv.com/panel/ja-solar-jam66d46-720-lb) | [Longi Solar LR7-72HVHF-670M](https://comparepv.com/panel/longi-lr7-72hvhf-670m) |
| Manufacturer | JA Solar | Longi Solar |
| Power | 720 Wp | 670 Wp |
| Efficiency | 23.20 % | 24.80 % |
| Technology | TOPCon | N-type |


## Where they differ

Ranked by how much the difference matters, not by datasheet order.


| Parameter | JAM66D46-720/LB | LR7-72HVHF-670M | Difference |
| --- | --- | --- | --- |
| Module efficiency | 23.20 % | 24.80 % | +1.60 pp for LR7-72HVHF-670M |
| Rated power | 720 Wp | 670 Wp | +50 W for JAM66D46-720/LB |
| Power density | 231.8 Wp/m² | 248.0 Wp/m² | +16.3 Wp/m² for LR7-72HVHF-670M |
| Temperature coefficient | -0.290 %/°C | -0.260 %/°C | +0.030 %/°C for LR7-72HVHF-670M |
| Weight | 38.2 kg | 28.5 kg | -9.7 kg for LR7-72HVHF-670M |
| Weight per kWp | 53.1 kg/kWp | 42.5 kg/kWp | -10.5 kg/kWp for LR7-72HVHF-670M |
| Product warranty | 12 yrs | 15 yrs | +3 yrs for LR7-72HVHF-670M |
| Open-circuit voltage | 49.00 V | 54.30 V | 5.30 V apart |
| Short-circuit current | 18.59 A | 15.60 A | 2.99 A apart |
| Module area | 3.106 m² | 2.701 m² | 0.405 m² apart |
| Cell technology | TOPCon | N-type | TOPCon vs N-type |
| Annual degradation | 0.40 %/yr | 0.35 %/yr | -0.05 %/yr for LR7-72HVHF-670M |
| Current at max power | 17.48 A | 14.91 A | 2.57 A apart |
| Cell count | 132 | 144 | 12 cells apart |
| Voltage at max power | 41.19 V | 44.96 V | 3.77 V apart |
| Bifacial | Yes | No | Yes vs No |
| Dimensions | 2384x1303x33 mm | 2382x1134x30 mm | 2384x1303x33 mm vs 2382x1134x30 mm |


## Every compared parameter


| Parameter | JAM66D46-720/LB | LR7-72HVHF-670M |
| --- | --- | --- |
| Rated power | 720 Wp | 670 Wp |
| Module efficiency | 23.20 % | 24.80 % |
| Power density | 231.8 Wp/m² | 248.0 Wp/m² |
| Open-circuit voltage | 49.00 V | 54.30 V |
| Voltage at max power | 41.19 V | 44.96 V |
| Short-circuit current | 18.59 A | 15.60 A |
| Current at max power | 17.48 A | 14.91 A |
| Temperature coefficient | -0.290 %/°C | -0.260 %/°C |
| Dimensions | 2384x1303x33 mm | 2382x1134x30 mm |
| Module area | 3.106 m² | 2.701 m² |
| Weight | 38.2 kg | 28.5 kg |
| Weight per kWp | 53.1 kg/kWp | 42.5 kg/kWp |
| Product warranty | 12 yrs | 15 yrs |
| Performance warranty | 30 yrs | 30 yrs |
| Annual degradation | 0.40 %/yr | 0.35 %/yr |
| Cell technology | TOPCon | N-type |
| 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, JAM66D46-720/LB:** 24,157 kWh
- **Cumulative output, LR7-72HVHF-670M:** 22,655 kWh
- **Gap:** 1,502 kWh


## Output when hot


| Condition | Cell temperature | JAM66D46-720/LB | LR7-72HVHF-670M | Retained |
| --- | --- | --- | --- | --- |
| Standard test conditions | 25 °C | 720 W | 670 W | 100.0% of rated power |
| Cool, bright day | 40 °C | 689 W | 644 W | 95.7% of rated power |
| Typical summer roof | 55 °C | 657 W | 618 W | 91.3% of rated power |
| Hot roof | 70 °C | 626 W | 592 W | 87.0% of rated power |


## Against the whole database


| Measure | JAM66D46-720/LB | LR7-72HVHF-670M | Out of | Note |
| --- | --- | --- | --- | --- |
| Efficiency | #1,306 | #12 | 14,005 | LR7-72HVHF-670M leads by 1,294 places |
| Power density | #1,347 | #14 | 14,005 | LR7-72HVHF-670M leads by 1,333 places |
| Heat behaviour | #2,165 | #511 | 14,005 | LR7-72HVHF-670M leads by 1,654 places |
| Weight | #6,810 | #226 | 14,005 | LR7-72HVHF-670M leads by 6,584 places |
| Warranty | #21 | #21 | 14,005 | Tied - the same position in the database |
| Overall | #516 | #284 | 14,005 | LR7-72HVHF-670M leads by 232 places |


## Questions


### Which panel is better: JA Solar JAM66D46-720/LB or Longi Solar LR7-72HVHF-670M?

According to our database: **Longi Solar LR7-72HVHF-670M** has higher module efficiency (**24.80%** vs **23.20%**); **Longi Solar LR7-72HVHF-670M** tolerates heat better (temp coeff **-0.260%/°C** vs **-0.290%/°C**). See the full spec comparison and 30-year energy simulation above for a complete picture.


### What is the efficiency of JA Solar JAM66D46-720/LB and Longi Solar LR7-72HVHF-670M?

**JA Solar JAM66D46-720/LB** has a module efficiency of **23.20%**, while **Longi Solar LR7-72HVHF-670M** is **24.80%**. Higher efficiency means more electricity from the same roof area - useful when space is limited.


### What cell technology does JA Solar JAM66D46-720/LB use vs Longi Solar LR7-72HVHF-670M?

**JA Solar JAM66D46-720/LB** uses **TOPCon** cells; **Longi Solar LR7-72HVHF-670M** uses **N-type**. 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 JAM66D46-720/LB and Longi Solar LR7-72HVHF-670M?

**JA Solar JAM66D46-720/LB** has a **30 years** power warranty; **Longi Solar LR7-72HVHF-670M** 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 JAM66D46-720/LB and Longi Solar LR7-72HVHF-670M bifacial panels?

**JA Solar JAM66D46-720/LB** is bifacial (captures light from both faces); **Longi Solar LR7-72HVHF-670M** is monofacial. Bifacial panels work best on ground mounts or raised structures with a light-coloured surface underneath.


## Related comparisons

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- [JA Solar JAM66D46-720/LB vs JA Solar JAM66D46-715/LB](https://comparepv.com/compare/ja-solar-jam66d46-720-lb/ja-solar-jam66d46-715-lb) - One difference: module efficiency
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Source: https://comparepv.com/compare/ja-solar-jam66d46-720-lb/longi-lr7-72hvhf-670m

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.