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620W vs 640W 15 of 18 identical Swap Change panels

DAH Solar DHN-78X16/DG-620W vs DAH Solar DHN-78X16/DG-640W

DAH Solar
DHN-78X16/DG-620W
620 Wp 22.18 % TOPCon Bifacial Incomplete
Open panel page Datasheet PDF
VS
DAH Solar
DHN-78X16/DG-640W
640 Wp 22.90 % TOPCon Bifacial Incomplete
Open panel page Datasheet PDF
The verdict

640W leads on the differences that matter

The largest is module efficiency: 0.72 pp more efficient. 15 of 18 comparable parameters are identical, with 1 more left out because at least one datasheet does not publish it.

See all 3 differences
How alike are they
15 of 18 comparable
parameters are identical
identical differs not published
01

What actually differs

3 of 18 parameters
Parameter 620W 640W Difference
Module efficiency 22.18 % 22.90 % 0.72 pp more efficient
Power density 221.8 Wp/m² 229.0 Wp/m² 7.2 Wp/m² higher
Rated power 620 Wp 640 Wp 20 W more power
02

What it means on a roof

Thirty years of production
A 1.0% first-year loss then 0.40% a year, assumed for both panels, 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.
620W
20,802 kWh
640W
21,473 kWh
Lifetime gap
671 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario 620W 640W
Standard test conditions 25 °C 100.0% of rated power 620 W 640 W
Cool, bright day 40 °C 95.7% of rated power 593 W 612 W
Typical summer roof 55 °C 91.3% of rated power 566 W 584 W
Hot roof 70 °C 87.0% of rated power 539 W 556 W
03

Full specification

Parameter 620W 640W Difference
Power and efficiency
Rated power 620 Wp 640 Wp +20 W for 640W
Module efficiency 22.18 % 22.90 % +0.72 pp for 640W
Power density 221.8 Wp/m² 229.0 Wp/m² +7.2 Wp/m² for 640W
Open-circuit voltage 55.60 V 56.40 V Effectively the same
Voltage at max power 46.80 V 47.60 V Effectively the same
Short-circuit current 14.08 A 14.32 A Effectively the same
Current at max power 13.25 A 13.45 A Effectively the same
Temperature
Temperature coefficient -0.290 %/°C -0.290 %/°C Same
Mechanical
Dimensions 2465x1134x34 mm 2465x1134x34 mm Same
Module area 2.795 m² 2.795 m² Same
Weight 34.2 kg 34.2 kg Same
Weight per kWp 55.2 kg/kWp 53.4 kg/kWp Effectively the same
Warranty and degradation
Product warranty 15 yrs 15 yrs Same
Performance warranty 30 yrs 30 yrs Same
Annual degradation - - Neither datasheet publishes this
Technology
Cell technology TOPCon TOPCon Same
Cell type Monocrystalline Monocrystalline Same
Cell count 156 156 Same
Bifacial Yes Yes Same
04

Against the whole database

14,005 panels
Efficiency
#5,930 vs #2,359
640W leads by 3,571 places
Power density
#5,869 vs #2,389
640W leads by 3,480 places
Heat behaviour
#2,165 vs #2,165
Tied - the same position in the database
Weight
#9,586 vs #7,363
640W leads by 2,223 places
Warranty
#21 vs #21
Tied - the same position in the database
Overall
#2,865 vs #1,704
640W leads by 1,161 places
05

More useful comparisons

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06

Written summary

07

Questions about this pairing

Which panel is better: DAH Solar DHN-78X16/DG-620W or DAH Solar DHN-78X16/DG-640W?
According to our database: DAH Solar DHN-78X16/DG-640 W has higher module efficiency (22.90% vs 22.18%). See the full spec comparison and 30-year energy simulation above for a complete picture.
What is the efficiency of DAH Solar DHN-78X16/DG-620W and DAH Solar DHN-78X16/DG-640W?
DAH Solar DHN-78X16/DG-620 W has a module efficiency of 22.18%, while DAH Solar DHN-78X16/DG-640 W is 22.90%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does DAH Solar DHN-78X16/DG-620W use vs DAH Solar DHN-78X16/DG-640W?
DAH Solar DHN-78X16/DG-620 W uses TOPCon cells; DAH Solar DHN-78X16/DG-640 W 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 DAH Solar DHN-78X16/DG-620W and DAH Solar DHN-78X16/DG-640W?
DAH Solar DHN-78X16/DG-620 W has a 30 years power warranty; DAH Solar DHN-78X16/DG-640 W 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 DAH Solar DHN-78X16/DG-620W and DAH Solar DHN-78X16/DG-640W bifacial panels?
Both DAH Solar DHN-78X16/DG-620 W and DAH Solar DHN-78X16/DG-640 W 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.