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Suntech STP660S-D66/Pmh+
Suntech Brand review

STP660S-D66/Pmh+

660 Wp TOPCon Bifacial 70%
ComparePV verdict

Middle of its segment, modest efficiency

Rank 2,643 of 14,129
Compare panels Datasheet PDF
Power (Wp)
660
Typical for its class
Efficiency (%)
21.20
Weak · bottom 4%
Density (Wp/m²)
212.5
Weak · bottom 5%
Temp (%/°C)
-0.340
Weak · bottom 6%
Weight (kg)
37.5
Weak · 2.9 kg above median
Warranty (yrs)
30
Typical · median 30 yrs

Ultra X Plus is a solar panel series built around 210mm monocrystalline silicon cells, designed for large-scale commercial and industrial installations where every square meter of roof or ground space counts. The use of PERC technology combined with half-cut and SMBB cell design helps reduce current losses and improve heat dissipation, allowing the modules to perform reliably even under high temperatures and partial shading. The series is available in both monofacial and bifacial configurations, giving investors the flexibility to choose the solution best suited to a specific site and their goal of maximizing energy yield from the rear side of the panel. The large cell format translates into high power density per module, which meaningfully lowers the per-watt cost of the installation (BoS) and shortens installation time for the same panel count. This makes it a solution aimed primarily at installers of solar farms and utility-scale projects seeking high efficiency and lower LCOE without compromising on mechanical durability, confirmed by resistance to heavy snow and wind loads. Ultra X Plus thus combines production scale, proven cell technology, and configuration flexibility in one market-mature series.

Ranking

254 panels in the segment TOPCon 650-700 W
Metric This panel Median Position in segment Overall rank
Module efficiency 21.20% 22.40% Weak · bottom 4% 9,145
Power density 212.5 223.7 Weak · bottom 5% 9,028
Temperature coefficient -0.340 -0.290 Weak · bottom 6% 8,846
Weight per kWp 56.8 53.1 Weak · bottom 12% 10,960
Performance warranty 30 yrs 30 yrs Typical 21
Colour key Strong - top 25% Typical - middle 50% Weak - bottom 25%

Signals from the data

0 positive · 3 caution
Best for

Utility-scale and shaded-installations.

Not ideal for

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

Watch-outs
21.20% module efficiency

Bottom 4% of the TOPCon 650-700 W segment, against a median of 22.40%. Ranked 9,145th in the whole database.

212.5 watts per square metre

Bottom 5% of the TOPCon 650-700 W segment, against a median of 223.7. Ranked 9,028th in the whole database.

-0.340 %/°C temperature coefficient

Bottom 6% of the TOPCon 650-700 W segment, against a median of -0.290. Ranked 8,846th in the whole database.

Notes from the database
  • At 21.2% efficiency, this panel is 1.2pp below the TOPCon 650-700W median of 22.4%
  • 212.5 W/m² power density is 11.2 W/m² below TOPCon 650-700W median (223.7 W/m²) - requires larger installation area
  • Temperature coefficient of -0.34%/°C is 0.05pp worse than TOPCon 650-700W median (-0.29%/°C) - higher losses in summer heat
  • Weight of 37.5 kg is 2.9 kg above TOPCon 650-700W median (34.6 kg) - verify structural support
  • 70% bifaciality enables rear-side power generation, boosting yield by 4-10% on reflective surfaces

Specifications

Open datasheet PDF
Nominal power (Pmax) 660 Wp Nameplate at 1000 W/m², 25 °C
Module efficiency 21.20 % Weak Segment median 22.40%
Vmpp · Impp 38.05 V · 17.35 A Operating point at max power
Voc · Isc 46.05 V · 18.35 A Sizes the string length
Max system voltage 1500 V Longer strings than 1000 V modules
Dimensions 2384×1303×35 mm · 3.11 m² of roof
Weight 37.5 kg Weak Weak · 2.9 kg above median
Cells 132 · TOPCon Monocrystalline
Bifaciality 70 % Rear output as a share of front
Coefficient Pmax -0.340 %/°C Weak bottom 6% of its segment
Coefficient Voc · Isc -0.260 · 0.050 %/°C
NOCT 42 °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 561 W guaranteed
Degradation 2.00 → 0.45 % First year, then annual

Datasheet charts

Open datasheet PDF

Measured curves published by Suntech in this model's datasheet. A chart carrying a wattage was measured on that variant alone - only the ones that describe 660 Wp appear here. The rest cover the whole series.

30-Year Linear Power Warranty (Degradation Curve) 30-Year Linear Power Warranty (Degradation Curve) 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
-0.340 %/°C against a segment median of -0.290
-
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
Suntech STP660S-D66/Pmh+ 660 W 21.20% -0.340 37.5 kg You are here
AIKO-A650-MAE72Mw 650 W 25.20% -0.260 27.0 kg Cooler, lighter, +4.0 pp
AIKO-A680-MDE72Mw 680 W 25.20% -0.260 29.0 kg Cooler, lighter, +4.0 pp
AIKO-A675-MDE72Mw 675 W 25.00% -0.260 29.0 kg Cooler, lighter, +3.8 pp
AIKO-A645-MAE72Mw 645 W 25.00% -0.260 27.0 kg Cooler, lighter, +3.8 pp
AIKO-A700-MAE78Dw 700 W 25.00% -0.260 34.5 kg +40 W, cooler, +3.8 pp
WST-675BKX72-A2 675 W 25.00% -0.260 32.1 kg Cooler, lighter, +3.8 pp
AIKO-A695-MAE78Dw 695 W 24.90% -0.260 34.5 kg +35 W, cooler, +3.7 pp
AIKO-G670-MCH72Mw 670 W 24.80% -0.260 28.2 kg Cooler, lighter, +3.6 pp
STP650S-D66/Pmh+ 650 W 20.90% -0.340 37.5 kg -10 W, -0.3 pp
STP655S-D66/Wmh 655 W 21.10% -0.340 33.5 kg Lighter, -5 yr warranty
STP665S-D66/Wmh 665 W 21.40% -0.340 33.5 kg Lighter, -5 yr warranty
STP670S-D66/Wmh 670 W 21.60% -0.340 33.5 kg Lighter, +0.4 pp, -5 yr warranty
STP675S-D66/Wmh 675 W 21.70% -0.340 33.5 kg Lighter, +0.5 pp, -5 yr warranty
AIKO-A805-GRH78Dw 805 W 25.10% -0.260 39.8 kg +145 W, cooler, +3.9 pp
AIKO-A800-GRH78Dw 800 W 24.90% -0.260 39.8 kg +140 W, cooler, +3.7 pp
AIKO-A795-GRH78Dw 795 W 24.80% -0.260 39.8 kg +135 W, cooler, +3.6 pp

Found 1393 panels of the same or similar size to this one, within ±10 mm. See them here Found 1403 panels of the same or similar size to this one, within ±25 mm. See them here Found 1403 panels of the same or similar size to this one, within ±50 mm. See them here Found 1435 panels of the same or similar size to this one, within ±100 mm. See them here

About the Ultra X Plus series

6 answered

These answers cover the whole series. Where a figure differs, the specification above is this module's own.

What is the maximum power output of the Suntech Ultra X Plus panel?
Panels in the Ultra X Plus series reach a maximum power output of up to 675 Wp. This is achieved through large 210 mm silicon cells combined with half-cut and SMBB technology, which increase power density within the module. As a result, fewer panels are needed to reach the same installed capacity, shortening installation time and reducing mounting structure costs.
What is TOPCon technology used in the Ultra X Plus, and how does it differ from PERC?
TOPCon (Tunnel Oxide Passivated Contact) is a newer-generation cell technology than PERC, used in the Ultra X Plus series. An additional passivation layer on the rear side of the cell reduces carrier recombination, resulting in higher module efficiency and a smaller power loss at high temperatures compared to standard PERC panels. In practice, this means higher energy yield, especially during summer and under high irradiance.
What warranty comes with Suntech Ultra X Plus panels?
The manufacturer provides a 15-year product warranty covering material and workmanship defects, along with a 30-year linear power output warranty. This means the panel must maintain a guaranteed percentage of its initial power throughout its service life, and as a Tier 1 manufacturer, Suntech offers reliable after-sales support for the entire warranty period.
Is the Suntech Ultra X Plus a bifacial panel?
No, this specific variant of the Ultra X Plus series is a monofacial module, generating energy only from the front side. The manufacturer also offers this series in a bifacial version, but choosing between the two depends on the mounting type and site conditions - the monofacial version is best suited for rooftops and installations without reflective ground surfaces.
Is Suntech a reliable manufacturer, and what does Tier 1 status mean?
Suntech is a Chinese manufacturer with Tier 1 status according to BloombergNEF's classification, indicating financial stability, in-house production lines, and a proven track record of supplying modules to large-scale energy projects worldwide. For investors, Tier 1 status matters for bank financing, as lenders and insurers often require Tier 1 panels as a condition for approving project loans.
Are Ultra X Plus panels suitable for large-scale solar farms?
Yes, the Ultra X Plus series was designed for commercial, industrial, and utility-scale installations. The large cell format and power output of up to 675 Wp reduce the number of panels, support structures, and cabling needed for a given installed capacity, directly lowering Balance of System (BoS) costs and the levelized cost of electricity (LCOE).
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