640Wp

Longi Solar Review

LR8-66HYD-640M

Name: Longi Solar LR8-66HYD-640M
Brand: Longi Solar

MonocrystallineBifacial

Datasheet

23.70%

Efficiency

236.9 Wp/m²

Power Density

-0.260%/°C

Temp. Coeff. Pmax chart

569W from 640W

Power after 30 years

Smart Insights (data-driven)

Efficiency of 23.7% matches the Back Contact 600-650W median
Power density of 236.9 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
Bifacial design (70% factor) captures reflected light - adds 4-10% yield on ground-mount or white roof

Price Offers 0

Shop	Country	Price	Price/kWp

Series Hi-MO 9 10 variants

All variants in this series

640W

23.7%

This panel

Show series details

Efficiency Range 23.1% - 24.8%

Avg. Efficiency 23.96%

Technology Back Contact

Dimensions 2382 × 1134 mm

Show series description

Longi Solar Hi-MO 9 is a breakthrough series of modules that redefines performance standards through the use of advanced HPBC 2.0 cell technology. This solution eliminates losses resulting from shading the front part of the cell by busbars, which directly translates into record efficiency and modern aesthetics. These panels are the ideal choice for investors seeking maximum energy yield from limited roof area, effectively solving the problem of space shortages in ambitious projects. Thanks to its optimized internal structure, Hi-MO 9 demonstrates exceptional resistance to degradation and stable operation even in low-light conditions, guaranteeing real gains on cloudy days. The innovative design also ensures an excellent temperature coefficient, limiting power drops during summer heat. This series is dedicated to both demanding households and large-scale solar farms, where the lowest levelized cost of energy is key. Compared to the competition, Hi-MO 9 stands out with a unique hybrid structure that combines the highest efficiency with long-term mechanical reliability. It is a safe and future-proof choice for anyone focusing on the highest quality of workmanship and the most modern technological thought in the photovoltaic industry.

Panels from the same series differ mainly in power output while having identical dimensions. Learn why →

Electrical Parameters (STC)

Nominal Power (Pmax)	640 Wp
Module Efficiency	23.70%
Voltage at Max Power (Vmpp)	41.00 V
Current at Max Power (Impp)	15.62 A
Open Circuit Voltage (Voc)	49.81 V
Short Circuit Current (Isc)	16.33 A
Max System Voltage	1500 V

Temperature Coefficients

Temp. Coeff. Pmax	-0.260%/°C
Temp. Coeff. Voc	-0.200%/°C
Temp. Coeff. Isc	0.050%/°C
NOCT	45°C

Cell Technology

Cell Type	Monocrystalline
Cell Count	132
Bifacial	Yes
Bifaciality Factor	70%

Dimensions & Weight

Length	2382 mm
Width	1134 mm
Height	30 mm
Weight	33.5 kg
Area	2.70 m²
Power Density	236.9 Wp/m²

Warranty

Product Warranty	12 years
Performance Warranty	30 years
End-of-Warranty Output	88.8%
First Year Degradation	1.00%
Annual Degradation	0.35%/year

Key Specifications

23.70%

Efficiency

640 Wp

Power

-0.26%/°C

Temp Coeff

30 yrs

Warranty

30-Year Degradation & Energy Production Simulation

Quick Presets

Irradiance (kWh/kWp/year) US avg: 1200-1800

Energy Price ($/kWh) Inflation: 0%

Energy Price Inflation (%/year)

Power after 30 years

Total Energy (30 yrs)

Energy Value

Efficiency & Power Over Time

Annual Energy Production

About the simulation: Calculations based on declared annual degradation (-%/year). Default irradiance (1200 kWh/kWp/year) is an average - check your exact value using PVGIS. Actual production depends on location, orientation, shading, and installation quality.

Power vs Cell Temperature Simulation (-0.260%/°C)

At 75°C (hot roof in summer):

Power: -

Power Loss: -

At Different Temperatures:

25°C (STC)	-
45°C	-
55°C	-
65°C	-
75°C	-

Your Temperature:

°C

Cell temperature of 75°C is typical for rooftop panels on a hot summer day at full irradiance. Temperature coefficient -0.260%/°C means power drops by this percentage for each degree above 25°C.

Bifacial Profit Calculator 70%

Select Surface Below Panel

What is albedo? Albedo is the fraction of sunlight reflected by a surface. Higher albedo (lighter surfaces) means more light reaches the back of bifacial panels, increasing total energy production.

Estimated Rear Gain

Front Power: -

Rear Gain: -

Total Effective Power: -

Calculation: Bifaciality (-) × Albedo × 0.6 (view factor)

This calculator uses a simplified model with default albedo values and a ground coverage factor of 0.6. Actual gain depends on installation conditions, tilt angle, mounting height, and season. For accurate calculations, we recommend measuring albedo on-site.

Sources: Sandia PVPMC (Albedo) · Bifacial Solar Guide · IEA PVPS

Similar Panels

Same series and power range as this panel

AIKO 650W

LR8-66HYD-640M

Price Offers 0

Series Hi-MO 9 10 variants

Electrical Parameters (STC)

Temperature Coefficients

Cell Technology

Dimensions & Weight

Warranty

Key Specifications

30-Year Degradation & Energy Production Simulation

Efficiency & Power Over Time

Annual Energy Production

Power vs Cell Temperature Simulation (-0.260%/°C)

At 75°C (hot roof in summer):

At Different Temperatures:

Your Temperature:

Bifacial Profit Calculator 70%

Select Surface Below Panel

Estimated Rear Gain

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