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LR7-54HJD-500M vs LR8-66HYD-670M 4 of 18 identical Swap Change panels

Longi Solar LR7-54HJD-500M vs Longi Solar LR8-66HYD-670M

Longi Solar LR7-54HJD-500M
LR7-54HJD-500M
500 Wp 24.50 % Back Contact Bifacial
Open panel page Datasheet PDF
VS
Longi Solar LR8-66HYD-670M
LR8-66HYD-670M
670 Wp 24.80 % Back Contact Bifacial Incomplete
Open panel page Datasheet PDF
The verdict

14 differences, and they point both ways

The largest is rated power: 170 W more power. 4 of 18 comparable parameters are identical, with 1 more left out because at least one datasheet does not publish it.

See all 14 differences
How alike are they
4 of 18 comparable
parameters are identical
identical differs not published
01

What actually differs

14 of 18 parameters
Parameter LR7-54HJD-500M LR8-66HYD-670M Difference
Rated power 500 Wp 670 Wp 170 W more power
Weight 23.5 kg 33.5 kg 10.0 kg lighter
Product warranty 30 yrs 12 yrs 18 yrs longer
Temperature coefficient -0.240 %/°C -0.260 %/°C 0.020 %/°C better in heat
Open-circuit voltage 41.35 V 50.12 V 8.77 V apart
Module area 2.041 m² 2.701 m² 0.660 m² apart
Module efficiency 24.50 % 24.80 % 0.30 pp more efficient
Short-circuit current 15.30 A 16.86 A 1.56 A apart
Weight per kWp 47.0 kg/kWp 50.0 kg/kWp 3.0 kg/kWp lighter
Power density 245.0 Wp/m² 248.0 Wp/m² 3.1 Wp/m² higher
Voltage at max power 34.17 V 41.38 V 7.21 V apart
Cell count 108 132 24 cells apart
Current at max power 14.63 A 16.19 A 1.56 A apart
Dimensions 1800x1134x30 mm 2382x1134x30 mm 1800x1134x30 mm vs 2382x1134x30 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
LR7-54HJD-500M
16,776 kWh
LR8-66HYD-670M
22,480 kWh
Lifetime gap
5,704 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario LR7-54HJD-500M LR8-66HYD-670M
Standard test conditions 25 °C 100.0% of rated power 500 W 670 W
Cool, bright day 40 °C 96.1% of rated power 482 W 644 W
Typical summer roof 55 °C 92.2% of rated power 464 W 618 W
Hot roof 70 °C 88.3% of rated power 446 W 592 W
03

Full specification

Parameter LR7-54HJD-500M LR8-66HYD-670M Difference
Power and efficiency
Rated power 500 Wp 670 Wp +170 W for LR8-66HYD-670M
Module efficiency 24.50 % 24.80 % +0.30 pp for LR8-66HYD-670M
Power density 245.0 Wp/m² 248.0 Wp/m² +3.1 Wp/m² for LR8-66HYD-670M
Open-circuit voltage 41.35 V 50.12 V 8.77 V apart
Voltage at max power 34.17 V 41.38 V 7.21 V apart
Short-circuit current 15.30 A 16.86 A 1.56 A apart
Current at max power 14.63 A 16.19 A 1.56 A apart
Temperature
Temperature coefficient -0.240 %/°C -0.260 %/°C +0.020 %/°C for LR7-54HJD-500M
Mechanical
Dimensions 1800x1134x30 mm 2382x1134x30 mm 1800x1134x30 mm vs 2382x1134x30 mm
Module area 2.041 m² 2.701 m² 0.660 m² apart
Weight 23.5 kg 33.5 kg -10.0 kg for LR7-54HJD-500M
Weight per kWp 47.0 kg/kWp 50.0 kg/kWp -3.0 kg/kWp for LR7-54HJD-500M
Warranty and degradation
Product warranty 30 yrs 12 yrs +18 yrs for LR7-54HJD-500M
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 108 132 24 cells apart
Bifacial Yes Yes Same
04

Against the whole database

14,005 panels
Efficiency
#74 vs #12
LR8-66HYD-670M leads by 62 places
Power density
#77 vs #14
LR8-66HYD-670M leads by 63 places
Heat behaviour
#13 vs #511
LR7-54HJD-500M leads by 498 places
Weight
#1,450 vs #3,317
LR7-54HJD-500M leads by 1,867 places
Warranty
#21 vs #21
Tied - the same position in the database
Overall
#1,611 vs #490
LR8-66HYD-670M leads by 1,121 places
05

More useful comparisons

Open the full database
Same series, other bin
Longi Solar LR7-54HJD-500M vs Longi Solar LR7-54HJD-510M
3 differences, the largest is module efficiency
Same series, other bin
Longi Solar LR7-54HJD-500M vs Longi Solar LR7-54HJD-505M
One difference: module efficiency
Same series, other bin
Longi Solar LR7-54HJD-500M vs Longi Solar LR7-54HJD-495M
One difference: module efficiency
Same series, other bin
Longi Solar LR8-66HYD-670M vs Longi Solar LR8-66HYD-665M
One difference: module efficiency
Same series, other bin
Longi Solar LR8-66HYD-670M vs Longi Solar LR8-66HYD-660M
3 differences, the largest is module efficiency
Same series, other bin
Longi Solar LR8-66HYD-670M vs Longi Solar LR7-72HYD-660M
9 differences, the largest is module efficiency
06

Written summary

07

Questions about this pairing

Which panel is better: Longi Solar LR7-54HJD-500M or Longi Solar LR8-66HYD-670M?
According to our database: Longi Solar LR8-66HYD-670M has higher module efficiency (24.80% vs 24.50%); Longi Solar LR7-54HJD-500M 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 LR7-54HJD-500M and Longi Solar LR8-66HYD-670M?
Longi Solar LR7-54HJD-500M has a module efficiency of 24.50%, while Longi Solar LR8-66HYD-670M is 24.80%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does Longi Solar LR7-54HJD-500M use vs Longi Solar LR8-66HYD-670M?
Longi Solar LR7-54HJD-500M uses Back Contact cells; Longi Solar LR8-66HYD-670M 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 LR7-54HJD-500M and Longi Solar LR8-66HYD-670M?
Longi Solar LR7-54HJD-500M has a 30 years power warranty; Longi Solar LR8-66HYD-670M 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 LR7-54HJD-500M and Longi Solar LR8-66HYD-670M bifacial panels?
Both Longi Solar LR7-54HJD-500M and Longi Solar LR8-66HYD-670M 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 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.