Suntech STP705S-D66-Nsh+ vs Suntech STP665S-D66/Wmh
VS
The verdict
STP705S-D66-Nsh+ leads on the differences that matter
The largest is module efficiency: 1.30 pp more efficient. 7 of 19 comparable parameters are identical.
See all 12 differencesHow alike are they
7
of 19 comparable
parameters are identical
parameters are identical
identical
differs
01
12 of 19 parameters
What actually differs
Parameter
STP705S-D66-Nsh+
STP665S-D66/Wmh
Difference
Module efficiency
22.70 %
21.40 %
1.30 pp more efficient
Temperature coefficient
-0.290 %/°C
-0.340 %/°C
0.050 %/°C better in heat
Rated power
705 Wp
665 Wp
40 W more power
Power density
227.0 Wp/m²
214.1 Wp/m²
12.9 Wp/m² higher
Performance warranty
30 yrs
25 yrs
5 yrs longer
Annual degradation
0.40 %/yr
0.55 %/yr
0.15 %/yr slower
Weight
38.5 kg
33.5 kg
5.0 kg lighter
Weight per kWp
54.6 kg/kWp
50.4 kg/kWp
4.2 kg/kWp lighter
Open-circuit voltage
48.57 V
46.25 V
2.32 V apart
Bifacial
Yes
No
Yes vs No
Voltage at max power
40.31 V
38.25 V
2.06 V apart
Dimensions
2384x1303x33 mm
2384x1303x35 mm
2384x1303x33 mm vs 2384x1303x35 mm
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
STP705S-D66-Nsh+
23,654 kWh
STP665S-D66/Wmh
21,552 kWh
Lifetime gap
2,102 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario
STP705S-D66-Nsh+
STP665S-D66/Wmh
Standard test conditions
25 °C
100.0% of rated power
705 W
665 W
Cool, bright day
40 °C
94.9% of rated power
674 W
631 W
Typical summer roof
55 °C
89.8% of rated power
644 W
597 W
Hot roof
70 °C
84.7% of rated power
613 W
563 W
03
Full specification
Parameter
STP705S-D66-Nsh+
STP665S-D66/Wmh
Difference
Power and efficiency
Rated power
705 Wp
665 Wp
+40 W for STP705S-D66-Nsh+
Module efficiency
22.70 %
21.40 %
+1.30 pp for STP705S-D66-Nsh+
Power density
227.0 Wp/m²
214.1 Wp/m²
+12.9 Wp/m² for STP705S-D66-Nsh+
Open-circuit voltage
48.57 V
46.25 V
2.32 V apart
Voltage at max power
40.31 V
38.25 V
2.06 V apart
Short-circuit current
18.43 A
18.39 A
Effectively the same
Current at max power
17.49 A
17.39 A
Effectively the same
Temperature
Temperature coefficient
-0.290 %/°C
-0.340 %/°C
+0.050 %/°C for STP705S-D66-Nsh+
Mechanical
Dimensions
2384x1303x33 mm
2384x1303x35 mm
2384x1303x33 mm vs 2384x1303x35 mm
Module area
3.106 m²
3.106 m²
Same
Weight
38.5 kg
33.5 kg
-5.0 kg for STP665S-D66/Wmh
Weight per kWp
54.6 kg/kWp
50.4 kg/kWp
-4.2 kg/kWp for STP665S-D66/Wmh
Warranty and degradation
Product warranty
12 yrs
12 yrs
Same
Performance warranty
30 yrs
25 yrs
+5 yrs for STP705S-D66-Nsh+
Annual degradation
0.40 %/yr
0.55 %/yr
-0.15 %/yr for STP705S-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
14,005 panels
Against the whole database
Efficiency
#3,307
vs
#8,323
STP705S-D66-Nsh+ leads by 5,016 places
Power density
#3,361
vs
#8,250
STP705S-D66-Nsh+ leads by 4,889 places
Heat behaviour
#2,165
vs
#8,778
STP705S-D66-Nsh+ leads by 6,613 places
Weight
#8,959
vs
#3,742
STP665S-D66/Wmh leads by 5,217 places
Warranty
#21
vs
#9,798
STP705S-D66-Nsh+ leads by 9,777 places
Overall
#1,037
vs
#3,792
STP705S-D66-Nsh+ leads by 2,755 places
05
Open the full database
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The same specification on paper
06
Written summary
Checking cache...
07
Questions about this pairing
Which panel is better: Suntech STP705S-D66-Nsh+ or Suntech STP665S-D66/Wmh?
According to our database: Suntech STP705S-D66-Nsh+ has higher module efficiency (22.70% vs 21.40%); Suntech STP705S-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 STP705S-D66-Nsh+ and Suntech STP665S-D66/Wmh?
Suntech STP705S-D66-Nsh+ has a module efficiency of 22.70%, 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 STP705S-D66-Nsh+ use vs Suntech STP665S-D66/Wmh?
Suntech STP705S-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 STP705S-D66-Nsh+ and Suntech STP665S-D66/Wmh?
Suntech STP705S-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 STP705S-D66-Nsh+ and Suntech STP665S-D66/Wmh bifacial panels?
Suntech STP705S-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 31 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.