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66HPH-515M vs 72HPH-555M 10 of 18 identical Swap Change panels

Longi Solar LR5-66HPH-515M vs Longi Solar LR5-72HPH-555M

Longi Solar LR5-66HPH-515M
LR5-66HPH-515M
515 Wp 21.70 %
Open panel page Datasheet PDF
VS
Longi Solar LR5-72HPH-555M
LR5-72HPH-555M
555 Wp 21.50 % PERC
Open panel page Datasheet PDF
The verdict

8 differences, and they point both ways

The largest is rated power: 40 W more power. 10 of 18 comparable parameters are identical, with 1 more left out because at least one datasheet does not publish it.

See all 8 differences
How alike are they
10 of 18 comparable
parameters are identical
identical differs not published
01

What actually differs

8 of 18 parameters
Parameter 66HPH-515M 72HPH-555M Difference
Rated power 515 Wp 555 Wp 40 W more power
Module area 2.373 m² 2.583 m² 0.210 m² apart
Open-circuit voltage 46.00 V 49.95 V 3.95 V apart
Weight 25.3 kg 27.5 kg 2.2 kg lighter
Module efficiency 21.70 % 21.50 % 0.20 pp more efficient
Cell count 132 144 12 cells apart
Voltage at max power 38.83 V 42.10 V 3.27 V apart
Dimensions 2093x1134x35 mm 2278x1134x35 mm 2093x1134x35 mm vs 2278x1134x35 mm
02

What it means on a roof

Thirty years of production
Each panel's own declared degradation curve, at 1,200 kWh/kWp a year
Same temp coeff. for both panels (-0.340 %/°C), so a warmer roof scales both curves by the same factor: the totals fall together and neither panel gains on the other.
66HPH-515M
16,691 kWh
72HPH-555M
17,987 kWh
Lifetime gap
1,296 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario 66HPH-515M 72HPH-555M
Standard test conditions 25 °C 100.0% of rated power 515 W 555 W
Cool, bright day 40 °C 94.9% of rated power 489 W 527 W
Typical summer roof 55 °C 89.8% of rated power 462 W 498 W
Hot roof 70 °C 84.7% of rated power 436 W 470 W
03

Full specification

Parameter 66HPH-515M 72HPH-555M Difference
Power and efficiency
Rated power 515 Wp 555 Wp +40 W for 72HPH-555M
Module efficiency 21.70 % 21.50 % +0.20 pp for 66HPH-515M
Power density 217.0 Wp/m² 214.8 Wp/m² Effectively the same
Open-circuit voltage 46.00 V 49.95 V 3.95 V apart
Voltage at max power 38.83 V 42.10 V 3.27 V apart
Short-circuit current 14.13 A 14.04 A Effectively the same
Current at max power 13.27 A 13.19 A Effectively the same
Temperature
Temperature coefficient -0.340 %/°C -0.340 %/°C Same
Mechanical
Dimensions 2093x1134x35 mm 2278x1134x35 mm 2093x1134x35 mm vs 2278x1134x35 mm
Module area 2.373 m² 2.583 m² 0.210 m² apart
Weight 25.3 kg 27.5 kg -2.2 kg for 66HPH-515M
Weight per kWp 49.1 kg/kWp 49.5 kg/kWp Effectively the same
Warranty and degradation
Product warranty 12 yrs 12 yrs Same
Performance warranty 25 yrs 25 yrs Same
Annual degradation 0.55 %/yr 0.55 %/yr Same
Technology
Cell technology - PERC Not published by Longi Solar
Cell type Monocrystalline Monocrystalline Same
Cell count 132 144 12 cells apart
Bifacial No No Same
04

Against the whole database

14,005 panels
Efficiency
#7,421 vs #7,958
66HPH-515M leads by 537 places
Power density
#7,426 vs #8,034
66HPH-515M leads by 608 places
Heat behaviour
#8,778 vs #8,778
Tied - the same position in the database
Weight
#2,764 vs #3,116
66HPH-515M leads by 352 places
Warranty
#9,798 vs #9,798
Tied - the same position in the database
Overall
#8,762 vs #7,542
72HPH-555M leads by 1,220 places
05

More useful comparisons

Open the full database
Same series, other bin
Longi Solar LR5-66HPH-515M vs Longi Solar LR5-72HPH-565M
8 differences, the largest is rated power
Same series, other bin
Longi Solar LR5-66HPH-515M vs Longi Solar LR5-72HPH-560M
7 differences, the largest is rated power
Same series, other bin
Longi Solar LR5-66HPH-515M vs Longi Solar LR5-72HPH-550M
9 differences, the largest is rated power
Same series, other bin
Longi Solar LR5-66HPH-515M vs Longi Solar LR5-72HPH-545M
9 differences, the largest is module efficiency
Same series, other bin
Longi Solar LR5-66HPH-515M vs Longi Solar LR5-66HPH-510M
One difference: module efficiency
Same series, other bin
Longi Solar LR5-66HPH-515M vs Longi Solar LR5-54HPH-425M
7 differences, the largest is rated power
06

Written summary

07

Questions about this pairing

Which panel is better: Longi Solar LR5-66HPH-515M or Longi Solar LR5-72HPH-555M?
According to our database: Longi Solar LR5-66HPH-515M has higher module efficiency (21.70% vs 21.50%). See the full spec comparison and 30-year energy simulation above for a complete picture.
What is the efficiency of Longi Solar LR5-66HPH-515M and Longi Solar LR5-72HPH-555M?
Longi Solar LR5-66HPH-515M has a module efficiency of 21.70%, while Longi Solar LR5-72HPH-555M is 21.50%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does Longi Solar LR5-66HPH-515M use vs Longi Solar LR5-72HPH-555M?
Longi Solar LR5-66HPH-515M uses Monocrystalline cells; Longi Solar LR5-72HPH-555M 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 Longi Solar LR5-66HPH-515M and Longi Solar LR5-72HPH-555M?
Longi Solar LR5-66HPH-515M has a 25 years power warranty; Longi Solar LR5-72HPH-555M 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.

Shop prices: See 147 Longi 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.