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66HPH-510M vs 54HPH-425M 10 of 18 identical Swap Change panels

Longi Solar LR5-66HPH-510M vs Longi Solar LR5-54HPH-425M

Longi Solar LR5-66HPH-510M
LR5-66HPH-510M
510 Wp 21.50 %
Open panel page Datasheet PDF
VS
Longi Solar LR5-54HPH-425M
LR5-54HPH-425M
425 Wp 21.80 % PERC
Open panel page Datasheet PDF
The verdict

8 differences, and they point both ways

The largest is rated power: 85 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-510M 54HPH-425M Difference
Rated power 510 Wp 425 Wp 85 W more power
Weight 25.3 kg 20.8 kg 4.5 kg lighter
Open-circuit voltage 45.85 V 37.96 V 7.89 V apart
Module area 2.373 m² 1.953 m² 0.421 m² apart
Module efficiency 21.50 % 21.80 % 0.30 pp more efficient
Voltage at max power 38.68 V 31.94 V 6.74 V apart
Cell count 132 108 24 cells apart
Dimensions 2093x1134x35 mm 1722x1134x30 mm 2093x1134x35 mm vs 1722x1134x30 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-510M
16,529 kWh
54HPH-425M
13,774 kWh
Lifetime gap
2,755 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario 66HPH-510M 54HPH-425M
Standard test conditions 25 °C 100.0% of rated power 510 W 425 W
Cool, bright day 40 °C 94.9% of rated power 484 W 403 W
Typical summer roof 55 °C 89.8% of rated power 458 W 382 W
Hot roof 70 °C 84.7% of rated power 432 W 360 W
03

Full specification

Parameter 66HPH-510M 54HPH-425M Difference
Power and efficiency
Rated power 510 Wp 425 Wp +85 W for 66HPH-510M
Module efficiency 21.50 % 21.80 % +0.30 pp for 54HPH-425M
Power density 214.9 Wp/m² 217.6 Wp/m² Effectively the same
Open-circuit voltage 45.85 V 37.96 V 7.89 V apart
Voltage at max power 38.68 V 31.94 V 6.74 V apart
Short-circuit current 14.05 A 14.08 A Effectively the same
Current at max power 13.19 A 13.31 A Effectively the same
Temperature
Temperature coefficient -0.340 %/°C -0.340 %/°C Same
Mechanical
Dimensions 2093x1134x35 mm 1722x1134x30 mm 2093x1134x35 mm vs 1722x1134x30 mm
Module area 2.373 m² 1.953 m² 0.421 m² apart
Weight 25.3 kg 20.8 kg -4.5 kg for 54HPH-425M
Weight per kWp 49.6 kg/kWp 48.9 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 132 108 24 cells apart
Bifacial No No Same
04

Against the whole database

14,005 panels
Efficiency
#7,958 vs #7,022
54HPH-425M leads by 936 places
Power density
#8,033 vs #7,172
54HPH-425M leads by 861 places
Heat behaviour
#8,778 vs #8,778
Tied - the same position in the database
Weight
#3,154 vs #2,624
54HPH-425M leads by 530 places
Warranty
#9,798 vs #9,798
Tied - the same position in the database
Overall
#9,133 vs #10,867
66HPH-510M leads by 1,734 places
05

More useful comparisons

Open the full database
Same series, other bin
Longi Solar LR5-66HPH-510M vs Longi Solar LR5-72HPH-565M
9 differences, the largest is rated power
Same series, other bin
Longi Solar LR5-66HPH-510M vs Longi Solar LR5-72HPH-560M
8 differences, the largest is rated power
Same series, other bin
Longi Solar LR5-66HPH-510M vs Longi Solar LR5-72HPH-555M
7 differences, the largest is rated power
Same series, other bin
Longi Solar LR5-66HPH-510M vs Longi Solar LR5-72HPH-550M
8 differences, the largest is rated power
Same series, other bin
Longi Solar LR5-66HPH-510M vs Longi Solar LR5-72HPH-545M
9 differences, the largest is rated power
Same series, other bin
Longi Solar LR5-66HPH-510M vs Longi Solar LR5-66HPH-515M
One difference: module efficiency
06

Written summary

07

Questions about this pairing

Which panel is better: Longi Solar LR5-66HPH-510M or Longi Solar LR5-54HPH-425M?
According to our database: Longi Solar LR5-54HPH-425M has higher module efficiency (21.80% 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-510M and Longi Solar LR5-54HPH-425M?
Longi Solar LR5-66HPH-510M has a module efficiency of 21.50%, while Longi Solar LR5-54HPH-425M is 21.80%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does Longi Solar LR5-66HPH-510M use vs Longi Solar LR5-54HPH-425M?
Longi Solar LR5-66HPH-510M uses Monocrystalline cells; Longi Solar LR5-54HPH-425M 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-510M and Longi Solar LR5-54HPH-425M?
Longi Solar LR5-66HPH-510M has a 25 years power warranty; Longi Solar LR5-54HPH-425M 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.