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645Wp
Longi Solar LR8-66HVD-645M
Longi Solar Review

LR8-66HVD-645M

MonocrystallineBifacial
Datasheet
23.88%
Efficiency
238.8 Wp/m²
Power Density
-0.260%/°C
Temp. Coeff. Pmax chart
573W from 645W
Power after 30 years
Smart Insights (data-driven)
  • Efficiency of 23.9% matches the Back Contact 600-650W median
  • Power density of 238.8 W/m² matches the Back Contact 600-650W median
  • At -0.26%/°C, hot weather performance is typical for Back Contact 600-650W panels
  • 33.5 kg weight exceeds %!s(float64=1.1000000000000014) median by %!f(string=B) kg (32.4 kg) - heavier for installation crews
  • Bifaciality factor of 75% can add 4-11% extra yield with reflective mounting surface
Performance Profile
Price Offers 0
Shop Country Price Price/kWp
Series Hi-MO X10 Scientist / LR8-66HVD 640~665M 6 variants
Efficiency Range 23.7% - 24.6%
Avg. Efficiency 24.16%
Technology Back Contact
Dimensions 2382 × 1134 mm
Show series description

This Longi Solar Hi-MO X10 Scientist LR8-66HVD 640-665M series is designed for investors seeking maximum energy production from limited roof space and reliable performance in real-world conditions. The application of N-TaiRay cells and HPBC 2.0 architecture enables better light utilization and minimizes typical losses associated with conventional modules featuring visible front grids. The result is not only high efficiency but also more predictable energy generation under variable sunlight conditions.

A practical advantage of this series is A+ Anti-Shading – a solution that supports energy gains when the module is partially shaded by a chimney, tree, or structural elements. Furthermore, the construction is engineered for safety by reducing the risk of hotspots and offering lower susceptibility to micro-cracks.

This is an excellent choice for modern residential installations and premium projects where yield, aesthetics (lack of visible front gridlines), and durability are prioritized over the compromises typical of less expensive solutions.

Panels from the same series differ mainly in power output while having identical dimensions. Learn why →
Electrical Parameters (STC)
Nominal Power (Pmax)645 Wp
Module Efficiency23.88%
Voltage at Max Power (Vmpp)40.88 V
Current at Max Power (Impp)15.78 A
Open Circuit Voltage (Voc)49.62 V
Short Circuit Current (Isc)16.46 A
Max System Voltage1500 V
Temperature Coefficients
Temp. Coeff. Pmax-0.260%/°C
Temp. Coeff. Voc-0.200%/°C
Temp. Coeff. Isc0.050%/°C
NOCT45°C
Cell Technology
Cell TypeMonocrystalline
Cell Count132
BifacialYes
Bifaciality Factor75%
Dimensions & Weight
Length2382 mm
Width1134 mm
Height30 mm
Weight33.5 kg
Area2.70 m²
Power Density238.8 Wp/m²
Warranty
Product Warranty15 years
Performance Warranty30 years
End-of-Warranty Output88.8%
First Year Degradation1.00%
Annual Degradation0.35%/year
Key Specifications
23.88%
Efficiency
645 Wp
Power
-0.26%/°C
Temp Coeff
30 yrs
Warranty
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