Longi Solar LR8-66HVD-645M vs Longi Solar LR7-54HJD-510M
VS
The verdict
LR7-54HJD-510M leads on the differences that matter
The largest is module efficiency: 1.12 pp more efficient. 5 of 19 comparable parameters are identical.
See all 14 differencesHow alike are they
5
of 19 comparable
parameters are identical
parameters are identical
identical
differs
01
14 of 19 parameters
What actually differs
Parameter
LR8-66HVD-645M
LR7-54HJD-510M
Difference
Module efficiency
23.88 %
25.00 %
1.12 pp more efficient
Rated power
645 Wp
510 Wp
135 W more power
Power density
238.8 Wp/m²
249.9 Wp/m²
11.1 Wp/m² higher
Weight
33.5 kg
23.5 kg
10.0 kg lighter
Product warranty
15 yrs
30 yrs
15 yrs longer
Temperature coefficient
-0.260 %/°C
-0.240 %/°C
0.020 %/°C better in heat
Weight per kWp
51.9 kg/kWp
46.1 kg/kWp
5.9 kg/kWp lighter
Open-circuit voltage
49.62 V
41.55 V
8.07 V apart
Module area
2.701 m²
2.041 m²
0.660 m² apart
Voltage at max power
40.88 V
34.37 V
6.51 V apart
Cell count
132
108
24 cells apart
Short-circuit current
16.46 A
15.52 A
0.94 A apart
Dimensions
2382x1134x30 mm
1800x1134x30 mm
2382x1134x30 mm vs 1800x1134x30 mm
Current at max power
15.78 A
14.84 A
0.94 A apart
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
LR8-66HVD-645M
21,809 kWh
LR7-54HJD-510M
17,245 kWh
Lifetime gap
4,564 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario
LR8-66HVD-645M
LR7-54HJD-510M
Standard test conditions
25 °C
100.0% of rated power
645 W
510 W
Cool, bright day
40 °C
96.1% of rated power
620 W
492 W
Typical summer roof
55 °C
92.2% of rated power
595 W
473 W
Hot roof
70 °C
88.3% of rated power
570 W
455 W
03
Full specification
Parameter
LR8-66HVD-645M
LR7-54HJD-510M
Difference
Power and efficiency
Rated power
645 Wp
510 Wp
+135 W for LR8-66HVD-645M
Module efficiency
23.88 %
25.00 %
+1.12 pp for LR7-54HJD-510M
Power density
238.8 Wp/m²
249.9 Wp/m²
+11.1 Wp/m² for LR7-54HJD-510M
Open-circuit voltage
49.62 V
41.55 V
8.07 V apart
Voltage at max power
40.88 V
34.37 V
6.51 V apart
Short-circuit current
16.46 A
15.52 A
0.94 A apart
Current at max power
15.78 A
14.84 A
0.94 A apart
Temperature
Temperature coefficient
-0.260 %/°C
-0.240 %/°C
+0.020 %/°C for LR7-54HJD-510M
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-510M
Weight per kWp
51.9 kg/kWp
46.1 kg/kWp
-5.9 kg/kWp for LR7-54HJD-510M
Warranty and degradation
Product warranty
15 yrs
30 yrs
+15 yrs for LR7-54HJD-510M
Performance warranty
30 yrs
30 yrs
Same
Annual degradation
0.35 %/yr
0.35 %/yr
Same
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
#394
vs
#4
LR7-54HJD-510M leads by 390 places
Power density
#356
vs
#7
LR7-54HJD-510M leads by 349 places
Heat behaviour
#511
vs
#13
LR7-54HJD-510M leads by 498 places
Weight
#5,361
vs
#979
LR7-54HJD-510M leads by 4,382 places
Warranty
#21
vs
#21
Tied - the same position in the database
Overall
#1,084
vs
#1,144
LR8-66HVD-645M leads by 60 places
05
Open the full database
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The same specification on paper
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Longi Solar LR8-66HVD-645M vs Longi Solar LR8-66HVD-640M
The same specification on paper
Same series, other bin
Longi Solar LR7-54HJD-510M vs Longi Solar LR7-54HJD-505M
One difference: module efficiency
06
Written summary
Checking cache...
07
Questions about this pairing
Which panel is better: Longi Solar LR8-66HVD-645M or Longi Solar LR7-54HJD-510M?
According to our database: Longi Solar LR7-54HJD-510M has higher module efficiency (25.00% vs 23.88%); Longi Solar LR7-54HJD-510M 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 LR8-66HVD-645M and Longi Solar LR7-54HJD-510M?
Longi Solar LR8-66HVD-645M has a module efficiency of 23.88%, while Longi Solar LR7-54HJD-510M is 25.00%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does Longi Solar LR8-66HVD-645M use vs Longi Solar LR7-54HJD-510M?
Longi Solar LR8-66HVD-645M uses Back Contact cells; Longi Solar LR7-54HJD-510M 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 LR8-66HVD-645M and Longi Solar LR7-54HJD-510M?
Longi Solar LR8-66HVD-645M has a 30 years power warranty; Longi Solar LR7-54HJD-510M 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 LR8-66HVD-645M and Longi Solar LR7-54HJD-510M bifacial panels?
Both Longi Solar LR8-66HVD-645M and Longi Solar LR7-54HJD-510M 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.