Longi Solar LR8-66HYD-665M vs Longi Solar LR7-72HYD-655M
VS
The verdict
LR8-66HYD-665M leads on the differences that matter
The largest is module efficiency: 0.40 pp more efficient. 9 of 18 comparable parameters are identical, with 1 more left out because at least one datasheet does not publish it.
See all 9 differencesHow alike are they
9
of 18 comparable
parameters are identical
parameters are identical
identical
differs
not published
01
9 of 18 parameters
What actually differs
Parameter
LR8-66HYD-665M
LR7-72HYD-655M
Difference
Module efficiency
24.60 %
24.20 %
0.40 pp more efficient
Open-circuit voltage
50.02 V
54.32 V
4.30 V apart
Short-circuit current
16.78 A
15.22 A
1.56 A apart
Cell technology
Back Contact
N-type
Back Contact vs N-type
Power density
246.2 Wp/m²
242.5 Wp/m²
3.7 Wp/m² higher
Rated power
665 Wp
655 Wp
10 W more power
Cell count
132
144
12 cells apart
Voltage at max power
41.28 V
44.97 V
3.69 V apart
Current at max power
16.11 A
14.57 A
1.54 A apart
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
Same temp coeff. for both panels (-0.260 %/°C), so a warmer roof scales both curves by the same factor: the totals fall together and neither panel gains on the other.
LR8-66HYD-665M
22,312 kWh
LR7-72HYD-655M
21,977 kWh
Lifetime gap
335 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario
LR8-66HYD-665M
LR7-72HYD-655M
Standard test conditions
25 °C
100.0% of rated power
665 W
655 W
Cool, bright day
40 °C
96.1% of rated power
639 W
629 W
Typical summer roof
55 °C
92.2% of rated power
613 W
604 W
Hot roof
70 °C
88.3% of rated power
587 W
578 W
03
Full specification
Parameter
LR8-66HYD-665M
LR7-72HYD-655M
Difference
Power and efficiency
Rated power
665 Wp
655 Wp
+10 W for LR8-66HYD-665M
Module efficiency
24.60 %
24.20 %
+0.40 pp for LR8-66HYD-665M
Power density
246.2 Wp/m²
242.5 Wp/m²
+3.7 Wp/m² for LR8-66HYD-665M
Open-circuit voltage
50.02 V
54.32 V
4.30 V apart
Voltage at max power
41.28 V
44.97 V
3.69 V apart
Short-circuit current
16.78 A
15.22 A
1.56 A apart
Current at max power
16.11 A
14.57 A
1.54 A apart
Temperature
Temperature coefficient
-0.260 %/°C
-0.260 %/°C
Same
Mechanical
Dimensions
2382x1134x30 mm
2382x1134x30 mm
Same
Module area
2.701 m²
2.701 m²
Same
Weight
33.5 kg
33.5 kg
Same
Weight per kWp
50.4 kg/kWp
51.1 kg/kWp
Effectively the same
Warranty and degradation
Product warranty
12 yrs
12 yrs
Same
Performance warranty
30 yrs
30 yrs
Same
Annual degradation
-
0.35 %/yr
Not published by Longi Solar
Technology
Cell technology
Back Contact
N-type
Back Contact vs N-type
Cell type
Monocrystalline
Monocrystalline
Same
Cell count
132
144
12 cells apart
Bifacial
Yes
Yes
Same
04
14,005 panels
Against the whole database
Efficiency
#51
vs
#184
LR8-66HYD-665M leads by 133 places
Power density
#42
vs
#172
LR8-66HYD-665M leads by 130 places
Heat behaviour
#511
vs
#511
Tied - the same position in the database
Weight
#3,742
vs
#4,503
LR8-66HYD-665M leads by 761 places
Warranty
#21
vs
#21
Tied - the same position in the database
Overall
#643
vs
#1,007
LR8-66HYD-665M leads by 364 places
05
Open the full database
More useful comparisons
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Longi Solar LR8-66HYD-665M vs Longi Solar LR8-66HYD-660M
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Longi Solar LR8-66HYD-665M vs Longi Solar LR7-72HYD-660M
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Longi Solar LR8-66HYD-665M vs Longi Solar LR7-72HYD-650M
9 differences, the largest is module efficiency
06
Written summary
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07
Questions about this pairing
Which panel is better: Longi Solar LR8-66HYD-665M or Longi Solar LR7-72HYD-655M?
According to our database: Longi Solar LR8-66HYD-665M has higher module efficiency (24.60% vs 24.20%). 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 LR7-72HYD-655M?
Longi Solar LR8-66HYD-665M has a module efficiency of 24.60%, while Longi Solar LR7-72HYD-655M is 24.20%. 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 LR7-72HYD-655M?
Longi Solar LR8-66HYD-665M uses Back Contact cells; Longi Solar LR7-72HYD-655M uses N-type. 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 LR7-72HYD-655M?
Longi Solar LR8-66HYD-665M has a 30 years power warranty; Longi Solar LR7-72HYD-655M 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 LR7-72HYD-655M bifacial panels?
Both Longi Solar LR8-66HYD-665M and Longi Solar LR7-72HYD-655M 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.