JAM72S20-470/MR vs JAM66D46-740/LB 5 of 19 identical Swap Change panels

JA Solar JAM72S20-470/MR vs JA Solar JAM66D46-740/LB

Q: Which panel is better: JA Solar JAM72S20-470/MR or JA Solar JAM66D46-740/LB?

According to our database: JA Solar JAM66D46-740/LB has higher module efficiency (23.80% vs 21.20%); JA Solar JAM66D46-740/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.

Q: What is the efficiency of JA Solar JAM72S20-470/MR and JA Solar JAM66D46-740/LB?

JA Solar JAM72S20-470/MR has a module efficiency of 21.20%, while JA Solar JAM66D46-740/LB is 23.80%. Higher efficiency means more electricity from the same roof area - useful when space is limited.

Q: What cell technology does JA Solar JAM72S20-470/MR use vs JA Solar JAM66D46-740/LB?

JA Solar JAM72S20-470/MR uses PERC cells; JA Solar JAM66D46-740/LB uses TOPCon. Modern n-type technologies (TOPCon, HJT, BC) typically deliver higher efficiency and lower degradation compared to older PERC (p-type) cells.

Q: What is the warranty on JA Solar JAM72S20-470/MR and JA Solar JAM66D46-740/LB?

JA Solar JAM72S20-470/MR has a 25 years power warranty; JA Solar JAM66D46-740/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.

Q: Are JA Solar JAM72S20-470/MR and JA Solar JAM66D46-740/LB bifacial panels?

JA Solar JAM66D46-740/LB is bifacial (captures light from both faces); JA Solar JAM72S20-470/MR is monofacial. Bifacial panels work best on ground mounts or raised structures with a light-coloured surface underneath.

JAM72S20-470/MR

470 Wp 21.20 % PERC

Open panel page Datasheet PDF

JAM66D46-740/LB

740 Wp 23.80 % TOPCon Bifacial

Open panel page Datasheet PDF

The verdict

JAM66D46-740/LB leads on the differences that matter

The largest is module efficiency: 2.60 pp more efficient. 5 of 19 comparable parameters are identical.

See all 14 differences

How alike are they

5 of 19 comparable
parameters are identical

identical differs

What actually differs

14 of 19 parameters

Parameter JAM72S20-470/MR JAM66D46-740/LB Difference

Module efficiency 21.20 % 23.80 % 2.60 pp more efficient

Temperature coefficient -0.350 %/°C -0.290 %/°C 0.060 %/°C better in heat

Rated power 470 Wp 740 Wp 270 W more power

Power density 211.5 Wp/m² 238.2 Wp/m² 26.7 Wp/m² higher

Performance warranty 25 yrs 30 yrs 5 yrs longer

Annual degradation 0.55 %/yr 0.40 %/yr 0.15 %/yr slower

Weight 24.5 kg 38.2 kg 13.7 kg lighter

Short-circuit current 11.53 A 18.73 A 7.20 A apart

Module area 2.222 m² 3.106 m² 0.885 m² apart

Cell technology PERC TOPCon PERC vs TOPCon

Current at max power 11.01 A 17.64 A 6.63 A apart

Cell count 144 132 12 cells apart

Bifacial No Yes No vs Yes

Dimensions 2112x1052x35 mm 2384x1303x33 mm 2112x1052x35 mm vs 2384x1303x33 mm

What it means on a roof

Thirty years of production

Each panel's own declared degradation curve, at 1,200 kWh/kWp a year

Cell temperature

JAM72S20-470/MR

15,232 kWh

JAM66D46-740/LB

24,828 kWh

Lifetime gap

9,596 kWh

Output when it is hot

Rated power carried across the range a module actually sees

Scenario JAM72S20-470/MR JAM66D46-740/LB

Standard test conditions 25 °C 100.0% of rated power 470 W 740 W

Cool, bright day 40 °C 94.8% of rated power 445 W 708 W

Typical summer roof 55 °C 89.5% of rated power 421 W 676 W

Hot roof 70 °C 84.2% of rated power 396 W 643 W

Full specification

Parameter JAM72S20-470/MR JAM66D46-740/LB Difference

Power and efficiency

Rated power 470 Wp 740 Wp +270 W for JAM66D46-740/LB

Module efficiency 21.20 % 23.80 % +2.60 pp for JAM66D46-740/LB

Power density 211.5 Wp/m² 238.2 Wp/m² +26.7 Wp/m² for JAM66D46-740/LB

Open-circuit voltage 50.31 V 49.80 V Effectively the same

Voltage at max power 42.69 V 41.96 V Effectively the same

Short-circuit current 11.53 A 18.73 A 7.20 A apart

Current at max power 11.01 A 17.64 A 6.63 A apart

Temperature

Temperature coefficient -0.350 %/°C -0.290 %/°C +0.060 %/°C for JAM66D46-740/LB

Mechanical

Dimensions 2112x1052x35 mm 2384x1303x33 mm 2112x1052x35 mm vs 2384x1303x33 mm

Module area 2.222 m² 3.106 m² 0.885 m² apart

Weight 24.5 kg 38.2 kg -13.7 kg for JAM72S20-470/MR

Weight per kWp 52.1 kg/kWp 51.6 kg/kWp Effectively the same

Warranty and degradation

Product warranty 12 yrs 12 yrs Same

Performance warranty 25 yrs 30 yrs +5 yrs for JAM66D46-740/LB

Annual degradation 0.55 %/yr 0.40 %/yr -0.15 %/yr for JAM66D46-740/LB

Technology

Cell technology PERC TOPCon PERC vs TOPCon

Cell type Monocrystalline Monocrystalline Same

Cell count 144 132 12 cells apart

Bifacial No Yes No vs Yes

Against the whole database

14,005 panels

Efficiency

#9,076 vs #433

JAM66D46-740/LB leads by 8,643 places

Power density

#9,193 vs #431

JAM66D46-740/LB leads by 8,762 places

Heat behaviour

#10,419 vs #2,165

JAM66D46-740/LB leads by 8,254 places

Weight

#5,602 vs #4,997

JAM66D46-740/LB leads by 605 places

Warranty

#9,798 vs #21

JAM66D46-740/LB leads by 9,777 places

Overall

#10,418 vs #185

JAM66D46-740/LB leads by 10,233 places

More useful comparisons

Open the full database

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JA Solar JAM72S20-470/MR vs JA Solar JAM72S20-455/MR

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JA Solar JAM72S20-470/MR vs JA Solar JAM72S20-450/MR

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JA Solar JAM72S20-470/MR vs JA Solar JAM72S20-445/MR

5 differences, the largest is module efficiency

Same series, other bin

JA Solar JAM66D46-740/LB vs JA Solar JAM66D46-735/LB

The same specification on paper

Written summary

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Questions about this pairing

Which panel is better: JA Solar JAM72S20-470/MR or JA Solar JAM66D46-740/LB?

According to our database: JA Solar JAM66D46-740/LB has higher module efficiency (23.80% vs 21.20%); JA Solar JAM66D46-740/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 JAM72S20-470/MR and JA Solar JAM66D46-740/LB?

JA Solar JAM72S20-470/MR has a module efficiency of 21.20%, while JA Solar JAM66D46-740/LB is 23.80%. Higher efficiency means more electricity from the same roof area - useful when space is limited.

What cell technology does JA Solar JAM72S20-470/MR use vs JA Solar JAM66D46-740/LB?

JA Solar JAM72S20-470/MR uses PERC cells; JA Solar JAM66D46-740/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 JAM72S20-470/MR and JA Solar JAM66D46-740/LB?

JA Solar JAM72S20-470/MR has a 25 years power warranty; JA Solar JAM66D46-740/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 JAM72S20-470/MR and JA Solar JAM66D46-740/LB bifacial panels?

JA Solar JAM66D46-740/LB is bifacial (captures light from both faces); JA Solar JAM72S20-470/MR is monofacial. Bifacial panels work best on ground mounts or raised structures with a light-coloured surface underneath.

Shop prices: See 391 JA Solar offers

Every figure here is from the manufacturers' own datasheets - a dash means the value is not published, never an estimate. The thirty-year projection and the temperature scenarios are calculations from those figures, and each states its assumption above.