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Longi Solar LR8-66HYD-655M
Longi Solar Brand review

LR8-66HYD-655M

655 Wp Back Contact Bifacial 70%
ComparePV verdict

Middle of its segment, heavy for its output

Rank 1,007 of 14,005
Compare panels Datasheet PDF
Power (Wp)
655
Typical for its class
Efficiency (%)
24.20
Typical · median 24.40%
Density (Wp/m²)
242.5
Typical · median 244.3
Temp (%/°C)
-0.260
Typical · median -0.260
Weight (kg)
33.5
Weak · 1.0 kg above median
Warranty (yrs)
30
Typical · median 30 yrs

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.

Ranking

80 panels in the segment Back Contact 650-700 W
Metric This panel Median Position in segment Overall rank
Module efficiency 24.20% 24.40% Typical 184
Power density 242.5 244.3 Typical 172
Temperature coefficient -0.260 -0.260 Typical 511
Weight per kWp 51.1 49.7 Weak · bottom 18% 4,503
Performance warranty 30 yrs 30 yrs Typical 21
Colour key Strong - top 25% Typical - middle 50% Weak - bottom 25%

Signals from the data

5 positive · 3 caution
Best for

Residential, utility-scale and hot-climate.

Not ideal for

Weight-limited structures.

Watch-outs
51.1 kg per kWp

Bottom 18% of the Back Contact 650-700 W segment, against a median of 49.7.

What owners get
Record 24.8% efficiency via HPBC 2.0

HPBC 2.0 back-contact cell technology eliminates front-side busbar shading, reaching up to 24.8% efficiency and 670 Wp. That is roughly 3.2 percentage points higher than comparable modules — Hiwatt HW-M12/132H (21.6%) and Techwise Summit Series / Resun RS9H-M (21.57% each) — at the same 670 Wp max power, yielding about 6.4% more installed capacity per equivalent roof area.

Very low power degradation

First-year degradation is capped at 1%, with no more than 0.35% annual degradation thereafter, retaining about 88.85% of original power output after 30 years. This clearly outperforms typical PERC modules with annual degradation around 0.5-0.6%.

30-year linear power warranty

The manufacturer covers the modules with a 30-year linear power warranty, longer than the industry-standard 25 years offered by most tier-1 manufacturers. Combined with the low degradation rate, this delivers a genuinely higher lifetime energy yield.

Strong temperature coefficient

The power temperature coefficient is -0.26%/°C, better than the typical -0.35% to -0.40%/°C for standard silicon modules. This means smaller power losses during summer heat, especially relevant in warmer climates.

Bankable Tier-1 manufacturer

LONGi Solar is a BNEF Tier-1 manufacturer, operating since 2000 and among the world's largest PV module suppliers. This bankability status eases project financing for large-scale installations and boosts confidence in warranty servicing.

Trade-offs
Shorter product warranty than some peers

The product warranty is 12 years, while some tier-1 competitors (e.g., other N-type TOPCon modules) offer 15-25 years of product warranty alongside the same 30-year power warranty. This gap is worth noting when comparing servicing terms.

Back-contact technology price premium

Back-contact (HPBC) modules typically carry a 5-10% price premium over comparable TOPCon modules due to the more complex cell manufacturing process without front-side busbars. This can raise project LCOE relative to cheaper TOPCon alternatives of similar power class.

Notes from the database
  • At 24.2% efficiency, this panel is on par with typical Back Contact 650-700W modules
  • At 242.5 W/m² power density, roof space requirements are typical for Back Contact 650-700W panels
  • At -0.26%/°C, hot weather performance is typical for Back Contact 650-700W panels
  • Weight of 33.5 kg is typical for Back Contact 650-700W panels
  • Bifacial design (70% factor) captures reflected light - adds 4-10% yield on ground-mount or white roof

Specifications

Open datasheet PDF
Nominal power (Pmax) 655 Wp Nameplate at 1000 W/m², 25 °C
Module efficiency 24.20 % Typical Segment median 24.40%
Vmpp · Impp 41.30 V · 15.87 A Operating point at max power
Voc · Isc 50.11 V · 16.57 A Sizes the string length
Max system voltage 1500 V Longer strings than 1000 V modules
Dimensions 2382×1134×30 mm · 2.70 m² of roof
Weight 33.5 kg Weak Weak · 1.0 kg above median
Cells 132 · Back Contact Monocrystalline
Bifaciality 70 % Rear output as a share of front
Coefficient Pmax -0.260 %/°C Typical median -0.260 of its segment
Coefficient Voc · Isc -0.200 · 0.050 %/°C
NOCT 45 °C At 800 W/m², 20 °C ambient
Product warranty 12 years Hardware defects only
Performance warranty 30 years Typical median 30 yrs · median 30 yrs
End-of-warranty output 88.8 % Equals 582 W guaranteed
Degradation 1.00 → 0.35 % First year, then annual

Datasheet charts

Open datasheet PDF

Measured curves published by Longi Solar in this model's datasheet. A chart carrying a wattage was measured on that variant alone - only the ones that describe 655 Wp appear here. The rest cover the whole series.

30-Year Power Warranty 30-Year Power Warranty Whole series

Simulations

Live - change any input
Lifetime output & value
30 years at 1200 kWh/kWp/year and €0.50 per kWh
Power in year 30
-
Lifetime energy
-
Energy value
-
With bifacial gain
-

Degradation from this panel's own datasheet figures. No inverter, soiling or shading losses.

Heat losses
-0.260 %/°C against a segment median of -0.260
-
Bifacial gain
Rear gain over light concrete: -
-

Model: bifaciality × albedo × 0.6 view factor. A first-order estimate, not a yield simulation.

Filter these
Size
Panel Power Eff. Temp. Weight Difference
Longi Solar LR8-66HYD-655M 655 W 24.20% -0.260 33.5 kg You are here
AIKO-A650-MAE72Mw 650 W 25.20% -0.260 27.0 kg Lighter, +1.0 pp
AIKO-A680-MDE72Mw 680 W 25.20% -0.260 29.0 kg +25 W, lighter, +1.0 pp
AIKO-A675-MDE72Mw 675 W 25.00% -0.260 29.0 kg +20 W, lighter, +0.8 pp
AIKO-A645-MAE72Mw 645 W 25.00% -0.260 27.0 kg -10 W, lighter, +0.8 pp
AIKO-A700-MAE78Dw 700 W 25.00% -0.260 34.5 kg +45 W, heavier, +0.8 pp
AIKO-A695-MAE78Dw 695 W 24.90% -0.260 34.5 kg +40 W, heavier, +0.7 pp
AIKO-G670-MCH72Mw 670 W 24.80% -0.260 28.2 kg +15 W, lighter, +0.6 pp
LR8-66HGD-595M 595 W 22.00% -0.280 32.5 kg -60 W, hotter, -2.2 pp
LR7-72HGD-600M 600 W 22.20% -0.280 33.5 kg -55 W, hotter, -2.0 pp
600M 600 W 22.40% -0.280 31.0 kg -55 W, -1.8 pp, -5 yr warranty
LR7-72HTH-605M 605 W 22.40% -0.280 28.5 kg -50 W, lighter, -1.8 pp
LR7-72HVHF-670M 670 W 24.80% -0.260 28.5 kg +15 W, lighter, +0.6 pp
JKM650-670N-66QL6-BDV (670W class) 670 W 24.80% -0.260 32.5 kg +15 W, lighter, +0.6 pp

Found 1119 panels of the same or similar size to this one, within ±10 mm. See them here Found 1125 panels of the same or similar size to this one, within ±25 mm. See them here Found 1236 panels of the same or similar size to this one, within ±50 mm. See them here Found 1917 panels of the same or similar size to this one, within ±100 mm. See them here

Common questions

6 answered
What is HPBC 2.0 technology in the Longi Hi-MO 9 and how does it differ from standard TOPCon cells?
HPBC 2.0 is a Back Contact cell technology in which all electrodes are moved to the rear side of the cell. With no busbars shading the front surface, the entire active area captures sunlight. As a result, the Hi-MO 9 achieves a module efficiency of 24.8% and a peak power of 670 Wp, outperforming typical TOPCon modules by approximately 40W in mass production. This translates directly into more energy per square meter of roof space.
What warranty does the Longi Solar Hi-MO 9 come with and what exactly does it cover?
Longi Solar provides a 12-year product warranty covering materials and workmanship, plus a 30-year linear power warranty. After 30 years, the module retains at least 87.4% of its rated power output. Annual degradation is 0.05 percentage points lower than conventional N-type products. As a Tier 1 manufacturer, Longi's financial stability supports the long-term enforceability of warranty claims.
Does the bifacial design of the Hi-MO 9 offer real benefits on a pitched residential roof?
Yes, though the rear-side gain depends on ground albedo and mounting clearance. The Hi-MO 9 achieves a bifaciality factor above 80%, which can add 5–10% extra energy output on light-colored roofing or above a white membrane. For roof-close installations the gain is smaller, but even a 10 cm air gap makes a measurable difference, especially in winter when snow-reflected irradiance can be significant.
How does the Hi-MO 9 perform in high summer temperatures and in low-light conditions?
The Back Contact architecture gives the Hi-MO 9 a temperature coefficient of approximately -0.26%/°C, one of the best figures in the 670 Wp class. Standard PERC modules typically rate at -0.35%/°C. On a hot day with the module at 45°C, the Hi-MO 9 loses roughly 5% less power than a PERC panel. Full-area passivation also improves low-irradiance response, maintaining stable generation on overcast days.
How many Longi Hi-MO 9 670 Wp panels do I need for a 10 kWp residential system?
At 670 Wp per panel, only 15 modules are needed to reach 10.05 kWp. Thanks to the 24.8% efficiency, each panel occupies significantly less roof area than conventional options — a standard 400 Wp module would require 25 panels for the same capacity. Fewer panels also means fewer mechanical and electrical connections, which can reduce installation labor costs.
Are Longi Hi-MO 9 panels compatible with popular inverters on the market?
Yes, the Hi-MO 9 670 Wp operates within the standard voltage and current ranges supported by inverters from Fronius, SMA, Huawei, Growatt, and SolarEdge. The higher short-circuit current (Isc approx. 18–19 A) means the inverter's MPPT input should be rated for at least 20 A. A qualified system designer will configure the correct stringing for Back Contact modules without any compatibility issues.
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