Tongwei TWMNH-66HD625 vs Tongwei TWMNH-66HD645
VS
The verdict
66HD645 leads on the differences that matter
The largest is module efficiency: 0.80 pp more efficient. 14 of 19 comparable parameters are identical.
See all 5 differencesHow alike are they
14
of 19 comparable
parameters are identical
parameters are identical
identical
differs
01
5 of 19 parameters
What actually differs
Parameter
66HD625
66HD645
Difference
Module efficiency
23.10 %
23.90 %
0.80 pp more efficient
Power density
231.4 Wp/m²
238.8 Wp/m²
7.4 Wp/m² higher
Rated power
625 Wp
645 Wp
20 W more power
Cell technology
TOPCon
N-type
TOPCon vs N-type
Weight per kWp
52.0 kg/kWp
49.9 kg/kWp
2.1 kg/kWp lighter
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
Same temp coeff. for both panels (-0.280 %/°C), so a warmer roof scales both curves by the same factor: the totals fall together and neither panel gains on the other.
66HD625
20,970 kWh
66HD645
21,641 kWh
Lifetime gap
671 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario
66HD625
66HD645
Standard test conditions
25 °C
100.0% of rated power
625 W
645 W
Cool, bright day
40 °C
95.8% of rated power
599 W
618 W
Typical summer roof
55 °C
91.6% of rated power
573 W
591 W
Hot roof
70 °C
87.4% of rated power
546 W
564 W
03
Full specification
Parameter
66HD625
66HD645
Difference
Power and efficiency
Rated power
625 Wp
645 Wp
+20 W for 66HD645
Module efficiency
23.10 %
23.90 %
+0.80 pp for 66HD645
Power density
231.4 Wp/m²
238.8 Wp/m²
+7.4 Wp/m² for 66HD645
Open-circuit voltage
49.30 V
49.85 V
Effectively the same
Voltage at max power
40.96 V
41.51 V
Effectively the same
Short-circuit current
16.12 A
16.39 A
Effectively the same
Current at max power
15.26 A
15.54 A
Effectively the same
Temperature
Temperature coefficient
-0.280 %/°C
-0.280 %/°C
Same
Mechanical
Dimensions
2382x1134x30 mm
2382x1134x30 mm
Same
Module area
2.701 m²
2.701 m²
Same
Weight
32.5 kg
32.2 kg
Effectively the same
Weight per kWp
52.0 kg/kWp
49.9 kg/kWp
-2.1 kg/kWp for 66HD645
Warranty and degradation
Product warranty
12 yrs
12 yrs
Same
Performance warranty
30 yrs
30 yrs
Same
Annual degradation
0.40 %/yr
0.40 %/yr
Same
Technology
Cell technology
TOPCon
N-type
TOPCon vs N-type
Cell type
Monocrystalline
Monocrystalline
Same
Cell count
132
132
Same
Bifacial
Yes
Yes
Same
04
14,269 panels
Against the whole database
Efficiency
#1,660
vs
#414
66HD645 leads by 1,246 places
Power density
#1,600
vs
#419
66HD645 leads by 1,181 places
Heat behaviour
#1,387
vs
#1,387
Tied - the same position in the database
Weight
#5,488
vs
#3,329
66HD645 leads by 2,159 places
Warranty
#31
vs
#31
Tied - the same position in the database
Overall
#2,340
vs
#1,371
66HD645 leads by 969 places
05
Open the full database
More useful comparisons
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Tongwei TWMNH-66HD625 vs Tongwei TWMNF-66HD750
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Tongwei TWMNH-66HD625 vs Tongwei TWMNF-66HD745
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Tongwei TWMNH-66HD625 vs Tongwei TWMNF-66HD740
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Same series, other bin
Tongwei TWMNH-66HD625 vs Tongwei TWMHF-66HD740X
14 differences, the largest is temperature coefficient
Same series, other bin
Tongwei TWMNH-66HD625 vs Tongwei TWMNF-66HD735
8 differences, the largest is rated power
Same series, other bin
Tongwei TWMNH-66HD625 vs Tongwei TWMHF-66HD735X
13 differences, the largest is temperature coefficient
06
Written summary
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07
Questions about this pairing
Which panel is better: Tongwei TWMNH-66HD625 or Tongwei TWMNH-66HD645?
According to our database: Tongwei TWMNH-66HD645 has higher module efficiency (23.90% vs 23.10%). See the full spec comparison and 30-year energy simulation above for a complete picture.
What is the efficiency of Tongwei TWMNH-66HD625 and Tongwei TWMNH-66HD645?
Tongwei TWMNH-66HD625 has a module efficiency of 23.10%, while Tongwei TWMNH-66HD645 is 23.90%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does Tongwei TWMNH-66HD625 use vs Tongwei TWMNH-66HD645?
Tongwei TWMNH-66HD625 uses TOPCon cells; Tongwei TWMNH-66HD645 uses N-type. 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 Tongwei TWMNH-66HD625 and Tongwei TWMNH-66HD645?
Tongwei TWMNH-66HD625 has a 30 years power warranty; Tongwei TWMNH-66HD645 has a 30 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 Tongwei TWMNH-66HD625 and Tongwei TWMNH-66HD645 bifacial panels?
Both Tongwei TWMNH-66HD625 and Tongwei TWMNH-66HD645 are bifacial - they capture reflected light from the ground, which can add 5-15% more annual energy on ground-mount or elevated rooftop installations with a light surface beneath.
Shop prices: See 56 Tongwei 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.