78X16/DG-640W vs 66Y18/DG-715 8 of 18 identical Swap Change panels

DAH Solar DHN-78X16/DG-640W vs DAH Solar DHN-66Y18/DG-715

Q: Which panel is better: DAH Solar DHN-78X16/DG-640W or DAH Solar DHN-66Y18/DG-715?

According to our database: DAH Solar DHN-66Y18/DG-715 has higher module efficiency (23.02% 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-78X16/DG-640W and DAH Solar DHN-66Y18/DG-715?

DAH Solar DHN-78X16/DG-640W has a module efficiency of 22.90%, while DAH Solar DHN-66Y18/DG-715 is 23.02%. Higher efficiency means more electricity from the same roof area - useful when space is limited.

Q: What cell technology does DAH Solar DHN-78X16/DG-640W use vs DAH Solar DHN-66Y18/DG-715?

DAH Solar DHN-78X16/DG-640W uses TOPCon cells; DAH Solar DHN-66Y18/DG-715 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-78X16/DG-640W and DAH Solar DHN-66Y18/DG-715?

DAH Solar DHN-78X16/DG-640W has a 30 years power warranty; DAH Solar DHN-66Y18/DG-715 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-78X16/DG-640W and DAH Solar DHN-66Y18/DG-715 bifacial panels?

Both DAH Solar DHN-78X16/DG-640W and DAH Solar DHN-66Y18/DG-715 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-78X16/DG-640W

640 Wp 22.90 % TOPCon Bifacial Incomplete

Open panel page Datasheet PDF

DAH Solar

DHN-66Y18/DG-715

715 Wp 23.02 % TOPCon Bifacial

Open panel page Datasheet PDF

The verdict

66Y18/DG-715 leads on the differences that matter

The largest is rated power: 75 W more power. 8 of 18 comparable parameters are identical, with 1 more left out because at least one datasheet does not publish it.

See all 10 differences

How alike are they

8 of 18 comparable
parameters are identical

identical differs not published

What actually differs

10 of 18 parameters

Parameter 78X16/DG-640W 66Y18/DG-715 Difference

Rated power 640 Wp 715 Wp 75 W more power

Open-circuit voltage 56.40 V 48.20 V 8.20 V apart

Short-circuit current 14.32 A 18.67 A 4.35 A apart

Module area 2.795 m² 3.106 m² 0.311 m² apart

Weight 34.2 kg 36.7 kg 2.5 kg lighter

Voltage at max power 47.60 V 40.60 V 7.00 V apart

Current at max power 13.45 A 17.61 A 4.16 A apart

Cell count 156 132 24 cells apart

Weight per kWp 53.4 kg/kWp 51.3 kg/kWp 2.1 kg/kWp lighter

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

78X16/DG-640W

21,473 kWh

66Y18/DG-715

23,990 kWh

Lifetime gap

2,517 kWh

Output when it is hot

Rated power carried across the range a module actually sees

Scenario 78X16/DG-640W 66Y18/DG-715

Standard test conditions 25 °C 100.0% of rated power 640 W 715 W

Cool, bright day 40 °C 95.7% of rated power 612 W 684 W

Typical summer roof 55 °C 91.3% of rated power 584 W 653 W

Hot roof 70 °C 87.0% of rated power 556 W 622 W

Full specification

Parameter 78X16/DG-640W 66Y18/DG-715 Difference

Power and efficiency

Rated power 640 Wp 715 Wp +75 W for 66Y18/DG-715

Module efficiency 22.90 % 23.02 % Effectively the same

Power density 229.0 Wp/m² 230.2 Wp/m² Effectively the same

Open-circuit voltage 56.40 V 48.20 V 8.20 V apart

Voltage at max power 47.60 V 40.60 V 7.00 V apart

Short-circuit current 14.32 A 18.67 A 4.35 A apart

Current at max power 13.45 A 17.61 A 4.16 A apart

Temperature

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

Mechanical

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

Module area 2.795 m² 3.106 m² 0.311 m² apart

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

Weight per kWp 53.4 kg/kWp 51.3 kg/kWp -2.1 kg/kWp for 66Y18/DG-715

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 156 132 24 cells apart

Bifacial Yes Yes Same

Against the whole database

14,005 panels

Efficiency

#2,359 vs #1,797

66Y18/DG-715 leads by 562 places

Power density

#2,389 vs #2,018

66Y18/DG-715 leads by 371 places

Heat behaviour

#2,165 vs #2,165

Tied - the same position in the database

Weight

#7,363 vs #4,703

66Y18/DG-715 leads by 2,660 places

Warranty

#21 vs #21

Tied - the same position in the database

Overall

#1,704 vs #439

66Y18/DG-715 leads by 1,265 places

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Written summary

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Questions about this pairing

Which panel is better: DAH Solar DHN-78X16/DG-640W or DAH Solar DHN-66Y18/DG-715?

According to our database: DAH Solar DHN-66Y18/DG-715 has higher module efficiency (23.02% 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-78X16/DG-640W and DAH Solar DHN-66Y18/DG-715?

DAH Solar DHN-78X16/DG-640 W has a module efficiency of 22.90%, while DAH Solar DHN-66Y18/DG-715 is 23.02%. Higher efficiency means more electricity from the same roof area - useful when space is limited.

What cell technology does DAH Solar DHN-78X16/DG-640W use vs DAH Solar DHN-66Y18/DG-715?

DAH Solar DHN-78X16/DG-640 W uses TOPCon cells; DAH Solar DHN-66Y18/DG-715 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-640W and DAH Solar DHN-66Y18/DG-715?

DAH Solar DHN-78X16/DG-640 W has a 30 years power warranty; DAH Solar DHN-66Y18/DG-715 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-640W and DAH Solar DHN-66Y18/DG-715 bifacial panels?

Both DAH Solar DHN-78X16/DG-640 W and DAH Solar DHN-66Y18/DG-715 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.