Longi Solar LR8-66HYD-665M vs Longi Solar LR7-54HJD-505M
VS
The verdict
LR7-54HJD-505M leads on the differences that matter
The largest is rated power: 160 W more power. 6 of 18 comparable parameters are identical, with 1 more left out because at least one datasheet does not publish it.
See all 12 differencesHow alike are they
6
of 18 comparable
parameters are identical
parameters are identical
identical
differs
not published
01
12 of 18 parameters
What actually differs
Parameter
LR8-66HYD-665M
LR7-54HJD-505M
Difference
Rated power
665 Wp
505 Wp
160 W more power
Weight
33.5 kg
23.5 kg
10.0 kg lighter
Product warranty
12 yrs
30 yrs
18 yrs longer
Temperature coefficient
-0.260 %/°C
-0.240 %/°C
0.020 %/°C better in heat
Open-circuit voltage
50.02 V
41.45 V
8.57 V apart
Module area
2.701 m²
2.041 m²
0.660 m² apart
Weight per kWp
50.4 kg/kWp
46.5 kg/kWp
3.8 kg/kWp lighter
Short-circuit current
16.78 A
15.41 A
1.37 A apart
Voltage at max power
41.28 V
34.27 V
7.01 V apart
Cell count
132
108
24 cells apart
Current at max power
16.11 A
14.74 A
1.37 A apart
Dimensions
2382x1134x30 mm
1800x1134x30 mm
2382x1134x30 mm vs 1800x1134x30 mm
02
What it means on a roof
Thirty years of production
A 1.0% first-year loss then 0.40% a year, assumed for both panels, at 1,200 kWh/kWp a year
LR8-66HYD-665M
22,312 kWh
LR7-54HJD-505M
16,944 kWh
Lifetime gap
5,368 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario
LR8-66HYD-665M
LR7-54HJD-505M
Standard test conditions
25 °C
100.0% of rated power
665 W
505 W
Cool, bright day
40 °C
96.1% of rated power
639 W
487 W
Typical summer roof
55 °C
92.2% of rated power
613 W
469 W
Hot roof
70 °C
88.3% of rated power
587 W
450 W
03
Full specification
Parameter
LR8-66HYD-665M
LR7-54HJD-505M
Difference
Power and efficiency
Rated power
665 Wp
505 Wp
+160 W for LR8-66HYD-665M
Module efficiency
24.60 %
24.70 %
Effectively the same
Power density
246.2 Wp/m²
247.4 Wp/m²
Effectively the same
Open-circuit voltage
50.02 V
41.45 V
8.57 V apart
Voltage at max power
41.28 V
34.27 V
7.01 V apart
Short-circuit current
16.78 A
15.41 A
1.37 A apart
Current at max power
16.11 A
14.74 A
1.37 A apart
Temperature
Temperature coefficient
-0.260 %/°C
-0.240 %/°C
+0.020 %/°C for LR7-54HJD-505M
Mechanical
Dimensions
2382x1134x30 mm
1800x1134x30 mm
2382x1134x30 mm vs 1800x1134x30 mm
Module area
2.701 m²
2.041 m²
0.660 m² apart
Weight
33.5 kg
23.5 kg
-10.0 kg for LR7-54HJD-505M
Weight per kWp
50.4 kg/kWp
46.5 kg/kWp
-3.8 kg/kWp for LR7-54HJD-505M
Warranty and degradation
Product warranty
12 yrs
30 yrs
+18 yrs for LR7-54HJD-505M
Performance warranty
30 yrs
30 yrs
Same
Annual degradation
-
0.35 %/yr
Not published by Longi Solar
Technology
Cell technology
Back Contact
Back Contact
Same
Cell type
Monocrystalline
Monocrystalline
Same
Cell count
132
108
24 cells apart
Bifacial
Yes
Yes
Same
04
14,005 panels
Against the whole database
Efficiency
#51
vs
#39
LR7-54HJD-505M leads by 12 places
Power density
#42
vs
#39
LR7-54HJD-505M leads by 3 places
Heat behaviour
#511
vs
#13
LR7-54HJD-505M leads by 498 places
Weight
#3,742
vs
#1,199
LR7-54HJD-505M leads by 2,543 places
Warranty
#21
vs
#21
Tied - the same position in the database
Overall
#643
vs
#1,425
LR8-66HYD-665M leads by 782 places
05
Open the full database
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06
Written summary
Checking cache...
07
Questions about this pairing
Which panel is better: Longi Solar LR8-66HYD-665M or Longi Solar LR7-54HJD-505M?
According to our database: Longi Solar LR7-54HJD-505M has higher module efficiency (24.70% vs 24.60%); Longi Solar LR7-54HJD-505M tolerates heat better (temp coeff -0.240%/°C vs -0.260%/°C). See the full spec comparison and 30-year energy simulation above for a complete picture.
What is the efficiency of Longi Solar LR8-66HYD-665M and Longi Solar LR7-54HJD-505M?
Longi Solar LR8-66HYD-665M has a module efficiency of 24.60%, while Longi Solar LR7-54HJD-505M is 24.70%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does Longi Solar LR8-66HYD-665M use vs Longi Solar LR7-54HJD-505M?
Longi Solar LR8-66HYD-665M uses Back Contact cells; Longi Solar LR7-54HJD-505M uses Back Contact. 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 LR8-66HYD-665M and Longi Solar LR7-54HJD-505M?
Longi Solar LR8-66HYD-665M has a 30 years power warranty; Longi Solar LR7-54HJD-505M 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 Longi Solar LR8-66HYD-665M and Longi Solar LR7-54HJD-505M bifacial panels?
Both Longi Solar LR8-66HYD-665M and Longi Solar LR7-54HJD-505M are bifacial - they capture reflected light from the ground, which can add 5-15% more annual energy on ground-mount or elevated rooftop installations with a light surface beneath.
Shop prices: See 174 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.