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STP700S-D66-Nsh+ vs STP665S-D66/Wmh 7 of 19 identical Swap Change panels

Suntech STP700S-D66-Nsh+ vs Suntech STP665S-D66/Wmh

Suntech STP700S-D66-Nsh+
STP700S-D66-Nsh+
700 Wp 22.50 % TOPCon Bifacial
VS
Suntech STP665S-D66/Wmh
STP665S-D66/Wmh
665 Wp 21.40 % TOPCon
The verdict

STP700S-D66-Nsh+ leads on the differences that matter

The largest is module efficiency: 1.10 pp more efficient. 7 of 19 comparable parameters are identical.

See all 12 differences
How alike are they
7 of 19 comparable
parameters are identical
identical differs
01

What actually differs

12 of 19 parameters
Parameter STP700S-D66-Nsh+ STP665S-D66/Wmh Difference
Module efficiency 22.50 % 21.40 % 1.10 pp more efficient
Temperature coefficient -0.290 %/°C -0.340 %/°C 0.050 %/°C better in heat
Performance warranty 30 yrs 25 yrs 5 yrs longer
Power density 225.3 Wp/m² 214.1 Wp/m² 11.3 Wp/m² higher
Rated power 700 Wp 665 Wp 35 W more power
Annual degradation 0.40 %/yr 0.55 %/yr 0.15 %/yr slower
Weight 37.5 kg 33.5 kg 4.0 kg lighter
Product warranty 15 yrs 12 yrs 3 yrs longer
Weight per kWp 53.6 kg/kWp 50.4 kg/kWp 3.2 kg/kWp lighter
Bifacial Yes No Yes vs No
Open-circuit voltage 47.65 V 46.25 V 1.40 V apart
Voltage at max power 39.65 V 38.25 V 1.40 V apart
02

What it means on a roof

Thirty years of production
Each panel's own declared degradation curve, at 1,200 kWh/kWp a year
STP700S-D66-Nsh+
23,486 kWh
STP665S-D66/Wmh
21,552 kWh
Lifetime gap
1,934 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario STP700S-D66-Nsh+ STP665S-D66/Wmh
Standard test conditions 25 °C 100.0% of rated power 700 W 665 W
Cool, bright day 40 °C 94.9% of rated power 670 W 631 W
Typical summer roof 55 °C 89.8% of rated power 639 W 597 W
Hot roof 70 °C 84.7% of rated power 609 W 563 W
03

Full specification

Parameter STP700S-D66-Nsh+ STP665S-D66/Wmh Difference
Power and efficiency
Rated power 700 Wp 665 Wp +35 W for STP700S-D66-Nsh+
Module efficiency 22.50 % 21.40 % +1.10 pp for STP700S-D66-Nsh+
Power density 225.3 Wp/m² 214.1 Wp/m² +11.3 Wp/m² for STP700S-D66-Nsh+
Open-circuit voltage 47.65 V 46.25 V 1.40 V apart
Voltage at max power 39.65 V 38.25 V 1.40 V apart
Short-circuit current 18.67 A 18.39 A Effectively the same
Current at max power 17.66 A 17.39 A Effectively the same
Temperature
Temperature coefficient -0.290 %/°C -0.340 %/°C +0.050 %/°C for STP700S-D66-Nsh+
Mechanical
Dimensions 2384x1303x35 mm 2384x1303x35 mm Same
Module area 3.106 m² 3.106 m² Same
Weight 37.5 kg 33.5 kg -4.0 kg for STP665S-D66/Wmh
Weight per kWp 53.6 kg/kWp 50.4 kg/kWp -3.2 kg/kWp for STP665S-D66/Wmh
Warranty and degradation
Product warranty 15 yrs 12 yrs +3 yrs for STP700S-D66-Nsh+
Performance warranty 30 yrs 25 yrs +5 yrs for STP700S-D66-Nsh+
Annual degradation 0.40 %/yr 0.55 %/yr -0.15 %/yr for STP700S-D66-Nsh+
Technology
Cell technology TOPCon TOPCon Same
Cell type Monocrystalline Monocrystalline Same
Cell count 132 132 Same
Bifacial Yes No Yes vs No
04

Against the whole database

14,005 panels
Efficiency
#4,222 vs #8,323
STP700S-D66-Nsh+ leads by 4,101 places
Power density
#3,989 vs #8,250
STP700S-D66-Nsh+ leads by 4,261 places
Heat behaviour
#2,165 vs #8,778
STP700S-D66-Nsh+ leads by 6,613 places
Weight
#7,586 vs #3,742
STP665S-D66/Wmh leads by 3,844 places
Warranty
#21 vs #9,798
STP700S-D66-Nsh+ leads by 9,777 places
Overall
#936 vs #3,792
STP700S-D66-Nsh+ leads by 2,856 places
05

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06

Written summary

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07

Questions about this pairing

Which panel is better: Suntech STP700S-D66-Nsh+ or Suntech STP665S-D66/Wmh?
According to our database: Suntech STP700S-D66-Nsh+ has higher module efficiency (22.50% vs 21.40%); Suntech STP700S-D66-Nsh+ tolerates heat better (temp coeff -0.290%/°C vs -0.340%/°C). See the full spec comparison and 30-year energy simulation above for a complete picture.
What is the efficiency of Suntech STP700S-D66-Nsh+ and Suntech STP665S-D66/Wmh?
Suntech STP700S-D66-Nsh+ has a module efficiency of 22.50%, while Suntech STP665S-D66/Wmh is 21.40%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does Suntech STP700S-D66-Nsh+ use vs Suntech STP665S-D66/Wmh?
Suntech STP700S-D66-Nsh+ uses TOPCon cells; Suntech STP665S-D66/Wmh uses TOPCon. Modern n-type technologies (TOPCon, HJT, BC) typically deliver higher efficiency and lower degradation compared to older PERC (p-type) cells.
What is the warranty on Suntech STP700S-D66-Nsh+ and Suntech STP665S-D66/Wmh?
Suntech STP700S-D66-Nsh+ has a 30 years power warranty; Suntech STP665S-D66/Wmh has a 25 years power warranty. The power warranty guarantees a minimum percentage of rated output at the end of the warranty period (typically 80-87%). Product (materials) warranties are usually shorter.
Are Suntech STP700S-D66-Nsh+ and Suntech STP665S-D66/Wmh bifacial panels?
Suntech STP700S-D66-Nsh+ is bifacial (captures light from both faces); Suntech STP665S-D66/Wmh is monofacial. Bifacial panels work best on ground mounts or raised structures with a light-coloured surface underneath.

Shop prices: See 22 Suntech offers

Every figure here is from the manufacturers' own datasheets - a dash means the value is not published, never an estimate. The thirty-year projection and the temperature scenarios are calculations from those figures, and each states its assumption above.