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LR8-66HYD-670M vs LR7-72HTDR-615M 6 of 18 identical Swap Change panels

Longi Solar LR8-66HYD-670M vs Longi Solar LR7-72HTDR-615M

Longi Solar LR8-66HYD-670M
LR8-66HYD-670M
670 Wp 24.80 % Back Contact Bifacial Incomplete
VS
Longi Solar LR7-72HTDR-615M
LR7-72HTDR-615M
615 Wp 22.80 % N-type Bifacial
The verdict

LR8-66HYD-670M leads on the differences that matter

The largest is module efficiency: 2.00 pp more efficient. 6 of 18 comparable parameters are identical, with 1 more left out because at least one datasheet does not publish it.

See all 12 differences
How alike are they
6 of 18 comparable
parameters are identical
identical differs not published
01

What actually differs

12 of 18 parameters
Parameter LR8-66HYD-670M LR7-72HTDR-615M Difference
Module efficiency 24.80 % 22.80 % 2.00 pp more efficient
Rated power 670 Wp 615 Wp 55 W more power
Power density 248.0 Wp/m² 227.7 Wp/m² 20.4 Wp/m² higher
Temperature coefficient -0.260 %/°C -0.280 %/°C 0.020 %/°C better in heat
Product warranty 12 yrs 15 yrs 3 yrs longer
Short-circuit current 16.86 A 14.75 A 2.11 A apart
Weight per kWp 50.0 kg/kWp 54.5 kg/kWp 4.5 kg/kWp lighter
Open-circuit voltage 50.12 V 52.96 V 2.84 V apart
Cell technology Back Contact N-type Back Contact vs N-type
Current at max power 16.19 A 13.78 A 2.41 A apart
Cell count 132 144 12 cells apart
Voltage at max power 41.38 V 44.63 V 3.25 V 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
LR8-66HYD-670M
22,480 kWh
LR7-72HTDR-615M
20,634 kWh
Lifetime gap
1,846 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario LR8-66HYD-670M LR7-72HTDR-615M
Standard test conditions 25 °C 100.0% of rated power 670 W 615 W
Cool, bright day 40 °C 95.8% of rated power 644 W 589 W
Typical summer roof 55 °C 91.6% of rated power 618 W 563 W
Hot roof 70 °C 87.4% of rated power 592 W 538 W
03

Full specification

Parameter LR8-66HYD-670M LR7-72HTDR-615M Difference
Power and efficiency
Rated power 670 Wp 615 Wp +55 W for LR8-66HYD-670M
Module efficiency 24.80 % 22.80 % +2.00 pp for LR8-66HYD-670M
Power density 248.0 Wp/m² 227.7 Wp/m² +20.4 Wp/m² for LR8-66HYD-670M
Open-circuit voltage 50.12 V 52.96 V 2.84 V apart
Voltage at max power 41.38 V 44.63 V 3.25 V apart
Short-circuit current 16.86 A 14.75 A 2.11 A apart
Current at max power 16.19 A 13.78 A 2.41 A apart
Temperature
Temperature coefficient -0.260 %/°C -0.280 %/°C +0.020 %/°C for LR8-66HYD-670M
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 50.0 kg/kWp 54.5 kg/kWp -4.5 kg/kWp for LR8-66HYD-670M
Warranty and degradation
Product warranty 12 yrs 15 yrs +3 yrs for LR7-72HTDR-615M
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

Against the whole database

14,005 panels
Efficiency
#12 vs #2,714
LR8-66HYD-670M leads by 2,702 places
Power density
#14 vs #3,077
LR8-66HYD-670M leads by 3,063 places
Heat behaviour
#511 vs #1,309
LR8-66HYD-670M leads by 798 places
Weight
#3,317 vs #8,815
LR8-66HYD-670M leads by 5,498 places
Warranty
#21 vs #21
Tied - the same position in the database
Overall
#490 vs #2,350
LR8-66HYD-670M leads by 1,860 places
05

More useful comparisons

Open the full database
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
Same series, other bin
Longi Solar LR8-66HYD-670M vs Longi Solar LR8-66HYD-655M
3 differences, the largest is module efficiency
Same series, other bin
Longi Solar LR8-66HYD-670M vs Longi Solar LR7-72HYD-655M
9 differences, the largest is module efficiency
Same series, other bin
Longi Solar LR8-66HYD-670M vs Longi Solar LR8-66HYD-650M
3 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-670M or Longi Solar LR7-72HTDR-615M?
According to our database: Longi Solar LR8-66HYD-670M has higher module efficiency (24.80% vs 22.80%); Longi Solar LR8-66HYD-670M tolerates heat better (temp coeff -0.260%/°C vs -0.280%/°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-670M and Longi Solar LR7-72HTDR-615M?
Longi Solar LR8-66HYD-670M has a module efficiency of 24.80%, while Longi Solar LR7-72HTDR-615M is 22.80%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does Longi Solar LR8-66HYD-670M use vs Longi Solar LR7-72HTDR-615M?
Longi Solar LR8-66HYD-670M uses Back Contact cells; Longi Solar LR7-72HTDR-615M 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-670M and Longi Solar LR7-72HTDR-615M?
Longi Solar LR8-66HYD-670M has a 30 years power warranty; Longi Solar LR7-72HTDR-615M 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-670M and Longi Solar LR7-72HTDR-615M bifacial panels?
Both Longi Solar LR8-66HYD-670M and Longi Solar LR7-72HTDR-615M 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.

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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.