66Y18/DG-725 vs 78X16/DG-640W 6 of 18 identical Swap Change panels

DAH Solar DHN-66Y18/DG-725 vs DAH Solar DHN-78X16/DG-640W

Q: Which panel is better: DAH Solar DHN-66Y18/DG-725 or DAH Solar DHN-78X16/DG-640W?

According to our database: DAH Solar DHN-66Y18/DG-725 has higher module efficiency (23.34% vs 22.90%). See the full spec comparison and 30-year energy simulation above for a complete picture.

Q: What is the efficiency of DAH Solar DHN-66Y18/DG-725 and DAH Solar DHN-78X16/DG-640W?

DAH Solar DHN-66Y18/DG-725 has a module efficiency of 23.34%, while DAH Solar DHN-78X16/DG-640W is 22.90%. Higher efficiency means more electricity from the same roof area - useful when space is limited.

Q: What cell technology does DAH Solar DHN-66Y18/DG-725 use vs DAH Solar DHN-78X16/DG-640W?

DAH Solar DHN-66Y18/DG-725 uses TOPCon cells; DAH Solar DHN-78X16/DG-640W uses TOPCon. Modern n-type technologies (TOPCon, HJT, BC) typically deliver higher efficiency and lower degradation compared to older PERC (p-type) cells.

Q: What is the warranty on DAH Solar DHN-66Y18/DG-725 and DAH Solar DHN-78X16/DG-640W?

DAH Solar DHN-66Y18/DG-725 has a 30 years power warranty; DAH Solar DHN-78X16/DG-640W 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.

Q: Are DAH Solar DHN-66Y18/DG-725 and DAH Solar DHN-78X16/DG-640W bifacial panels?

Both DAH Solar DHN-66Y18/DG-725 and DAH Solar DHN-78X16/DG-640W 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.

DAH Solar

DHN-66Y18/DG-725

725 Wp 23.34 % TOPCon Bifacial

Open panel page Datasheet PDF

DAH Solar

DHN-78X16/DG-640W

640 Wp 22.90 % TOPCon Bifacial Incomplete

Open panel page Datasheet PDF

The verdict

66Y18/DG-725 leads on the differences that matter

The largest is rated power: 85 W more power. 6 of 18 comparable parameters are identical, with 1 more left out because at least one datasheet does not publish it.

See all 12 differences

How alike are they

6 of 18 comparable
parameters are identical

identical differs not published

What actually differs

12 of 18 parameters

Parameter 66Y18/DG-725 78X16/DG-640W Difference

Rated power 725 Wp 640 Wp 85 W more power

Module efficiency 23.34 % 22.90 % 0.44 pp more efficient

Open-circuit voltage 48.60 V 56.40 V 7.80 V apart

Short-circuit current 18.79 A 14.32 A 4.47 A apart

Module area 3.106 m² 2.795 m² 0.311 m² apart

Weight 36.7 kg 34.2 kg 2.5 kg lighter

Power density 233.4 Wp/m² 229.0 Wp/m² 4.4 Wp/m² higher

Weight per kWp 50.6 kg/kWp 53.4 kg/kWp 2.8 kg/kWp lighter

Voltage at max power 41.00 V 47.60 V 6.60 V apart

Current at max power 17.68 A 13.45 A 4.23 A apart

Cell count 132 156 24 cells apart

Dimensions 2384x1303x33 mm 2465x1134x34 mm 2384x1303x33 mm vs 2465x1134x34 mm

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

Cell temperature

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.

66Y18/DG-725

24,325 kWh

78X16/DG-640W

21,473 kWh

Lifetime gap

2,852 kWh

Output when it is hot

Rated power carried across the range a module actually sees

Scenario 66Y18/DG-725 78X16/DG-640W

Standard test conditions 25 °C 100.0% of rated power 725 W 640 W

Cool, bright day 40 °C 95.7% of rated power 693 W 612 W

Typical summer roof 55 °C 91.3% of rated power 662 W 584 W

Hot roof 70 °C 87.0% of rated power 630 W 556 W

Full specification

Parameter 66Y18/DG-725 78X16/DG-640W Difference

Power and efficiency

Rated power 725 Wp 640 Wp +85 W for 66Y18/DG-725

Module efficiency 23.34 % 22.90 % +0.44 pp for 66Y18/DG-725

Power density 233.4 Wp/m² 229.0 Wp/m² +4.4 Wp/m² for 66Y18/DG-725

Open-circuit voltage 48.60 V 56.40 V 7.80 V apart

Voltage at max power 41.00 V 47.60 V 6.60 V apart

Short-circuit current 18.79 A 14.32 A 4.47 A apart

Current at max power 17.68 A 13.45 A 4.23 A apart

Temperature

Temperature coefficient -0.290 %/°C -0.290 %/°C Same

Mechanical

Dimensions 2384x1303x33 mm 2465x1134x34 mm 2384x1303x33 mm vs 2465x1134x34 mm

Module area 3.106 m² 2.795 m² 0.311 m² apart

Weight 36.7 kg 34.2 kg -2.5 kg for 78X16/DG-640W

Weight per kWp 50.6 kg/kWp 53.4 kg/kWp -2.8 kg/kWp for 66Y18/DG-725

Warranty and degradation

Product warranty 15 yrs 15 yrs Same

Performance warranty 30 yrs 30 yrs Same

Annual degradation 0.40 %/yr - Not published by DAH Solar

Technology

Cell technology TOPCon TOPCon Same

Cell type Monocrystalline Monocrystalline Same

Cell count 132 156 24 cells apart

Bifacial Yes Yes Same

Against the whole database

14,005 panels

Efficiency

#943 vs #2,359

66Y18/DG-725 leads by 1,416 places

Power density

#936 vs #2,389

66Y18/DG-725 leads by 1,453 places

Heat behaviour

#2,165 vs #2,165

Tied - the same position in the database

Weight

#4,067 vs #7,363

66Y18/DG-725 leads by 3,296 places

Warranty

#21 vs #21

Tied - the same position in the database

Overall

#251 vs #1,704

66Y18/DG-725 leads by 1,453 places

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Written summary

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Questions about this pairing

Which panel is better: DAH Solar DHN-66Y18/DG-725 or DAH Solar DHN-78X16/DG-640W?

According to our database: DAH Solar DHN-66Y18/DG-725 has higher module efficiency (23.34% vs 22.90%). See the full spec comparison and 30-year energy simulation above for a complete picture.

What is the efficiency of DAH Solar DHN-66Y18/DG-725 and DAH Solar DHN-78X16/DG-640W?

DAH Solar DHN-66Y18/DG-725 has a module efficiency of 23.34%, 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-66Y18/DG-725 use vs DAH Solar DHN-78X16/DG-640W?

DAH Solar DHN-66Y18/DG-725 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-66Y18/DG-725 and DAH Solar DHN-78X16/DG-640W?

DAH Solar DHN-66Y18/DG-725 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-66Y18/DG-725 and DAH Solar DHN-78X16/DG-640W bifacial panels?

Both DAH Solar DHN-66Y18/DG-725 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.

Shop prices: See 11 DAH Solar 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.