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Solarspace SS9-66HD-645M
Solarspace Brand review

SS9-66HD-645M

645 Wp PERC Bifacial 70%
ComparePV verdict

Strong in heat, modest efficiency

Rank 3,638 of 14,005
Compare panels Datasheet PDF
Power (Wp)
645
Strong · top 7%
Efficiency (%)
20.76
Weak · bottom 11%
Density (Wp/m²)
207.6
Weak · bottom 12%
Temp (%/°C)
-0.330
Strong · top 6%
Weight (kg)
37.5
Typical · median 34.0 kg
Warranty (yrs)
30
Typical · median 30 yrs

The Solarspace SS9-66HD 645-670M series are large-format modules designed to maximize energy yield from a limited surface area and ensure stable operation in demanding conditions. The use of bifacial construction allows for a real increase in energy production by utilizing reflected light from the ground - which works particularly well on roofs with light-colored membranes, carports, and ground-mounted installations.

The half-cut architecture also deserves attention, as it reduces losses at connections and improves the module's performance under partial shading - a common scenario, for example, along the edges of roofs, chimneys, or rows of structures. Another distinguishing feature is the anti-reflective glass coating, which supports efficient radiation collection in less favorable lighting conditions.

This is a good choice for investors who value not only high yield but also predictability - this is facilitated by the long linear power warranty and a robust, weather-resistant construction with a sealed connection box. The SS9-66HD series is aimed at C&I and PV farm projects, where performance from each module and ease of scalability are key.

Ranking

217 panels in the segment PERC 600-650 W
Metric This panel Median Position in segment Overall rank
Module efficiency 20.76% 21.38% Weak · bottom 11% 10,612
Power density 207.6 213.8 Weak · bottom 12% 10,562
Temperature coefficient -0.330 -0.340 Strong · top 6% 8,545
Weight per kWp 58.1 55.7 Typical 11,573
Performance warranty 30 yrs 30 yrs Typical 21
Colour key Strong - top 25% Typical - middle 50% Weak - bottom 25%

Signals from the data

1 positive · 2 caution
Best for

Commercial, utility-scale and shaded-installations.

Not ideal for

Tight roof space and roofs where every square metre has to count.

Strengths
-0.330 %/°C temperature coefficient

Top 6% of the PERC 600-650 W segment, against a median of -0.340. Ranked 8,545th in the whole database.

Watch-outs
20.76% module efficiency

Bottom 11% of the PERC 600-650 W segment, against a median of 21.38%.

207.6 watts per square metre

Bottom 12% of the PERC 600-650 W segment, against a median of 213.8.

Notes from the database
  • At 20.8% efficiency, this panel is 0.6pp below the PERC 600-650W median of 21.4%
  • 207.6 W/m² power density is 6.2 W/m² below PERC 600-650W median (213.8 W/m²) - requires larger installation area
  • Temperature coefficient of -0.33%/°C matches the PERC 600-650W median
  • At 37.5 kg, this panel is 3.5 kg heavier than the PERC 600-650W median (34.0 kg) - more demanding for installation crews
  • 70% bifaciality enables rear-side power generation, boosting yield by 4-10% on reflective surfaces

Specifications

Open datasheet PDF
Nominal power (Pmax) 645 Wp Nameplate at 1000 W/m², 25 °C
Module efficiency 20.76 % Weak Segment median 21.38%
Vmpp · Impp 37.71 V · 17.11 A Operating point at max power
Voc · Isc 45.31 V · 18.11 A Sizes the string length
Max system voltage 1500 V Longer strings than 1000 V modules
Dimensions 2384×1303×33 mm · 3.11 m² of roof
Weight 37.5 kg Typical Typical · median 34.0 kg
Cells 132 · PERC Monocrystalline
Bifaciality 70 % Rear output as a share of front
Coefficient Pmax -0.330 %/°C Strong top 6% of its segment
Coefficient Voc · Isc -0.260 · 0.046 %/°C
NOCT 45 °C At 800 W/m², 20 °C ambient
Product warranty 15 years Hardware defects only
Performance warranty 30 years Typical median 30 yrs · median 30 yrs
End-of-warranty output 85.0 % Equals 548 W guaranteed
Degradation 2.00 → 0.45 % First year, then annual

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
-0.330 %/°C against a segment median of -0.340
-
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
Solarspace SS9-66HD-645M 645 W 20.76% -0.330 37.5 kg You are here
AIKO-A650-MAE72Mw 650 W 25.20% -0.260 27.0 kg Cooler, lighter, +4.4 pp
AIKO-A680-MDE72Mw 680 W 25.20% -0.260 29.0 kg Cooler, lighter, +4.4 pp
AIKO-A675-MDE72Mw 675 W 25.00% -0.260 29.0 kg Cooler, lighter, +4.2 pp
AIKO-A645-MAE72Mw 645 W 25.00% -0.260 27.0 kg Cooler, lighter, +4.2 pp
AIKO-A695-MAE78Dw 695 W 24.90% -0.260 34.5 kg +50 W, cooler, +4.1 pp
AIKO-G670-MCH72Mw 670 W 24.80% -0.260 28.2 kg Cooler, lighter, +4.0 pp
LR7-72HVHF-670M 670 W 24.80% -0.260 28.5 kg Cooler, lighter, +4.0 pp
SS9-66HD-650M 650 W 20.92% -0.330 37.5 kg Very close match
SS9-66HD-655M 655 W 21.09% -0.330 37.5 kg +10 W, +0.3 pp
SS9-66HD-660M 660 W 21.25% -0.330 37.5 kg +15 W, +0.5 pp
SS9-66HD-665M 665 W 21.41% -0.330 37.5 kg +20 W, +0.6 pp
SS9-66HD-670M 670 W 21.57% -0.330 37.5 kg +25 W, +0.8 pp
SS9-66HD-675N 675 W 21.73% -0.290 37.5 kg +30 W, cooler, +1.0 pp
SS9-66HD-680N 680 W 21.89% -0.290 37.5 kg +35 W, cooler, +1.1 pp
SS9-66HD-685N 685 W 22.05% -0.290 37.5 kg +40 W, cooler, +1.3 pp
AIKO-A805-GRH78Dw 805 W 25.10% -0.260 39.8 kg +160 W, cooler, +4.3 pp

Found 1390 panels of the same or similar size to this one, within ±10 mm. See them here Found 1400 panels of the same or similar size to this one, within ±25 mm. See them here Found 1400 panels of the same or similar size to this one, within ±50 mm. See them here Found 1432 panels of the same or similar size to this one, within ±100 mm. See them here

Common questions

6 answered
What warranties come with the Solarspace SS9-66HD 645-670M modules?
The SS9-66HD 645-670M series carries a 15-year product warranty covering material defects and workmanship, plus a 30-year linear power warranty. A linear power warranty means degradation is spread evenly over time, so the module retains a significant portion of its rated output after three decades. This is one of the longer warranty standards available in the commercial PERC module segment.
What does bifacial mean for the SS9-66HD 645-670M and where does it make sense?
Bifacial means the module generates power from both sides — the front absorbs direct irradiance, while the rear captures light reflected off the ground or surface below. In the SS9-66HD 645-670M, this translates to measurable energy gains wherever ground albedo is high: white roofing membranes, gravel, concrete, or grass on ground-mount farms. On typical dark bituminous roofs, the rear-side gain is negligible.
Are the Solarspace SS9-66HD 645-670M panels suitable for ground-mount utility or C&I farms?
Yes, the SS9-66HD 645-670M series is designed primarily for C&I and utility-scale PV projects. High peak power up to 670 Wp reduces the total module count and shortens installation time. The bifacial design pairs well with high-albedo ground surfaces, and the large format is well suited to tracker or fixed-tilt ground-mount structures where scaling efficiency matters.
How do the SS9-66HD 645-670M modules handle partial shading?
The half-cut cell architecture splits each PERC cell into two halves, reducing resistive losses and limiting the impact of localized shading — from roof edges, chimneys, or inter-row shading on farms. It does not eliminate shading losses entirely, but ensures that a shaded portion of the module has less effect on the performance of the remaining cells in the string.
How heavy are the SS9-66HD 645-670M modules and are they difficult to install?
Modules in the SS9-66HD 645-670M series fall into the large-format category — estimated weight is approximately 37–38 kg with dimensions close to 2384×1303 mm. These are standard dimensions for the 660–670 Wp commercial class. Rooftop installation requires at least two technicians; for ground-mount farms these parameters are completely typical and pose no logistical challenge.
Is PERC technology in the SS9-66HD 645-670M outdated compared to TOPCon or HJT?
Bifacial half-cut PERC still delivers a strong price-to-yield ratio in the commercial segment. TOPCon and HJT achieve higher efficiency and a better temperature coefficient, but at a higher upfront cost. For PV farms and C&I projects where LCOE is the primary metric, 645–670 Wp PERC modules remain a competitive choice — especially from a Tier 1 manufacturer like Solarspace.
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