DMEGC DM635M10T-B78HSW vs DMEGC DM645M10T-B78HSW
VS
The verdict
DM645M10T-B78HSW leads on the differences that matter
The largest is module efficiency: 0.40 pp more efficient. 16 of 19 comparable parameters are identical.
See all 3 differencesHow alike are they
16
of 19 comparable
parameters are identical
parameters are identical
identical
differs
01
3 of 19 parameters
What actually differs
Parameter
DM635M10T-B78HSW
DM645M10T-B78HSW
Difference
Module efficiency
22.70 %
23.10 %
0.40 pp more efficient
Power density
227.2 Wp/m²
230.7 Wp/m²
3.6 Wp/m² higher
Rated power
635 Wp
645 Wp
10 W more power
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 (-0.290 %/°C), so a warmer roof scales both curves by the same factor: the totals fall together and neither panel gains on the other.
DM635M10T-B78HSW
21,306 kWh
DM645M10T-B78HSW
21,641 kWh
Lifetime gap
335 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario
DM635M10T-B78HSW
DM645M10T-B78HSW
Standard test conditions
25 °C
100.0% of rated power
635 W
645 W
Cool, bright day
40 °C
95.7% of rated power
607 W
617 W
Typical summer roof
55 °C
91.3% of rated power
580 W
589 W
Hot roof
70 °C
87.0% of rated power
552 W
561 W
03
Full specification
Parameter
DM635M10T-B78HSW
DM645M10T-B78HSW
Difference
Power and efficiency
Rated power
635 Wp
645 Wp
+10 W for DM645M10T-B78HSW
Module efficiency
22.70 %
23.10 %
+0.40 pp for DM645M10T-B78HSW
Power density
227.2 Wp/m²
230.7 Wp/m²
+3.6 Wp/m² for DM645M10T-B78HSW
Open-circuit voltage
57.50 V
57.90 V
Effectively the same
Voltage at max power
47.67 V
48.05 V
Effectively the same
Short-circuit current
14.09 A
14.19 A
Effectively the same
Current at max power
13.34 A
13.44 A
Effectively the same
Temperature
Temperature coefficient
-0.290 %/°C
-0.290 %/°C
Same
Mechanical
Dimensions
2465x1134x30 mm
2465x1134x30 mm
Same
Module area
2.795 m²
2.795 m²
Same
Weight
33.5 kg
33.5 kg
Same
Weight per kWp
52.8 kg/kWp
51.9 kg/kWp
Effectively the same
Warranty and degradation
Product warranty
15 yrs
15 yrs
Same
Performance warranty
30 yrs
30 yrs
Same
Annual degradation
0.40 %/yr
0.40 %/yr
Same
Technology
Cell technology
TOPCon
TOPCon
Same
Cell type
Monocrystalline
Monocrystalline
Same
Cell count
156
156
Same
Bifacial
Yes
Yes
Same
04
14,005 panels
Against the whole database
Efficiency
#3,307
vs
#1,570
DM645M10T-B78HSW leads by 1,737 places
Power density
#3,252
vs
#1,654
DM645M10T-B78HSW leads by 1,598 places
Heat behaviour
#2,165
vs
#2,165
Tied - the same position in the database
Weight
#6,429
vs
#5,361
DM645M10T-B78HSW leads by 1,068 places
Warranty
#21
vs
#21
Tied - the same position in the database
Overall
#1,913
vs
#1,491
DM645M10T-B78HSW leads by 422 places
05
Open the full database
More useful comparisons
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DMEGC DM635M10T-B78HSW vs DMEGC DM600M10T-B72HSW
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DMEGC DM635M10T-B78HSW vs DMEGC DM595M10T-B72HSW
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DMEGC DM635M10T-B78HSW vs DMEGC DM590M10T-B72HSW
7 differences, the largest is rated power
06
Written summary
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07
Questions about this pairing
Which panel is better: DMEGC DM635M10T-B78HSW or DMEGC DM645M10T-B78HSW?
According to our database: DMEGC DM645M10T-B78HSW has higher module efficiency (23.10% vs 22.70%). See the full spec comparison and 30-year energy simulation above for a complete picture.
What is the efficiency of DMEGC DM635M10T-B78HSW and DMEGC DM645M10T-B78HSW?
DMEGC DM635M10T-B78HSW has a module efficiency of 22.70%, while DMEGC DM645M10T-B78HSW is 23.10%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does DMEGC DM635M10T-B78HSW use vs DMEGC DM645M10T-B78HSW?
DMEGC DM635M10T-B78HSW uses TOPCon cells; DMEGC DM645M10T-B78HSW 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 DMEGC DM635M10T-B78HSW and DMEGC DM645M10T-B78HSW?
DMEGC DM635M10T-B78HSW has a 30 years power warranty; DMEGC DM645M10T-B78HSW 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 DMEGC DM635M10T-B78HSW and DMEGC DM645M10T-B78HSW bifacial panels?
Both DMEGC DM635M10T-B78HSW and DMEGC DM645M10T-B78HSW 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.
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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.