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TWMNH-66HD vs TNC M10-78 Bifacial 5 of 17 identical Swap Change panels

Tongwei TWMNH-66HD vs Tongwei TNC M10-78 Bifacial

TWMNH-66HD
620 Wp 22.95 % TOPCon Bifacial Incomplete
Open panel page Datasheet PDF
VS
TNC M10-78 Bifacial
635 Wp 22.70 % TOPCon
Open panel page Datasheet PDF
The verdict

TWMNH-66HD leads on the differences that matter

The largest is weight: 4.8 kg lighter. 5 of 17 comparable parameters are identical, with 2 more left out because at least one datasheet does not publish them.

See all 12 differences
How alike are they
5 of 17 comparable
parameters are identical
identical differs not published
01

What actually differs

12 of 17 parameters
Parameter TWMNH-66HD TNC M10-78 Bifacial Difference
Weight 29.0 kg 33.8 kg 4.8 kg lighter
Weight per kWp 46.8 kg/kWp 53.2 kg/kWp 6.5 kg/kWp lighter
Product warranty 15 yrs 12 yrs 3 yrs longer
Open-circuit voltage 49.10 V 57.20 V 8.10 V apart
Short-circuit current 16.06 A 13.82 A 2.24 A apart
Module area 2.701 m² 2.795 m² 0.094 m² apart
Module efficiency 22.95 % 22.70 % 0.25 pp more efficient
Rated power 620 Wp 635 Wp 15 W more power
Voltage at max power 40.82 V 48.05 V 7.23 V apart
Current at max power 15.19 A 13.22 A 1.97 A apart
Bifacial Yes No Yes vs No
Dimensions 2382x1134x30 mm 2465x1134 mm 2382x1134x30 mm vs 2465x1134 mm
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 (-0.280 %/°C), so a warmer roof scales both curves by the same factor: the totals fall together and neither panel gains on the other.
TWMNH-66HD
20,802 kWh
TNC M10-78 Bifacial
21,306 kWh
Lifetime gap
504 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario TWMNH-66HD TNC M10-78 Bifacial
Standard test conditions 25 °C 100.0% of rated power 620 W 635 W
Cool, bright day 40 °C 95.8% of rated power 594 W 608 W
Typical summer roof 55 °C 91.6% of rated power 568 W 582 W
Hot roof 70 °C 87.4% of rated power 542 W 555 W
03

Full specification

Parameter TWMNH-66HD TNC M10-78 Bifacial Difference
Power and efficiency
Rated power 620 Wp 635 Wp +15 W for TNC M10-78 Bifacial
Module efficiency 22.95 % 22.70 % +0.25 pp for TWMNH-66HD
Power density 229.5 Wp/m² 227.2 Wp/m² Effectively the same
Open-circuit voltage 49.10 V 57.20 V 8.10 V apart
Voltage at max power 40.82 V 48.05 V 7.23 V apart
Short-circuit current 16.06 A 13.82 A 2.24 A apart
Current at max power 15.19 A 13.22 A 1.97 A apart
Temperature
Temperature coefficient -0.280 %/°C -0.280 %/°C Same
Mechanical
Dimensions 2382x1134x30 mm 2465x1134 mm 2382x1134x30 mm vs 2465x1134 mm
Module area 2.701 m² 2.795 m² 0.094 m² apart
Weight 29.0 kg 33.8 kg -4.8 kg for TWMNH-66HD
Weight per kWp 46.8 kg/kWp 53.2 kg/kWp -6.5 kg/kWp for TWMNH-66HD
Warranty and degradation
Product warranty 15 yrs 12 yrs +3 yrs for TWMNH-66HD
Performance warranty 30 yrs 30 yrs Same
Annual degradation - 0.40 %/yr Not published by Tongwei
Technology
Cell technology TOPCon TOPCon Same
Cell type Monocrystalline Monocrystalline Same
Cell count 132 - Not published by Tongwei
Bifacial Yes No Yes vs No
04

Against the whole database

14,005 panels
Efficiency
#2,268 vs #3,307
TWMNH-66HD leads by 1,039 places
Power density
#2,191 vs #3,252
TWMNH-66HD leads by 1,061 places
Heat behaviour
#1,309 vs #1,309
Tied - the same position in the database
Weight
#1,343 vs #7,071
TWMNH-66HD leads by 5,728 places
Warranty
#21 vs #21
Tied - the same position in the database
Overall
#2,013 vs #2,385
TWMNH-66HD leads by 372 places
05

More useful comparisons

Open the full database
Same series, other bin
Tongwei TWMNH-66HD vs Tongwei THC G12-66 Bifacial
11 differences, the largest is module efficiency
Same series, other bin
Tongwei TWMNH-66HD vs Tongwei TWMNF-66HD
7 differences, the largest is rated power
Same series, other bin
Tongwei TWMNH-66HD vs Tongwei TWMNH-66HS
The same specification on paper
Same series, other bin
Tongwei TWMNH-66HD vs Tongwei TWMNH-54HD
6 differences, the largest is module efficiency
Same series, other bin
Tongwei TWMNH-66HD vs Tongwei TWMNH-48HC
6 differences, the largest is module efficiency
Same series, other bin
Tongwei TNC M10-78 Bifacial vs Tongwei TNC G12-66 Monofacial
9 differences, the largest is rated power
06

Written summary

07

Questions about this pairing

Which panel is better: Tongwei TWMNH-66HD or Tongwei TNC M10-78 Bifacial?
According to our database: Tongwei TWMNH-66HD has higher module efficiency (22.95% vs 22.70%). See the full spec comparison and 30-year energy simulation above for a complete picture.
What is the efficiency of Tongwei TWMNH-66HD and Tongwei TNC M10-78 Bifacial?
Tongwei TWMNH-66HD has a module efficiency of 22.95%, while Tongwei TNC M10-78 Bifacial is 22.70%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does Tongwei TWMNH-66HD use vs Tongwei TNC M10-78 Bifacial?
Tongwei TWMNH-66HD uses TOPCon cells; Tongwei TNC M10-78 Bifacial 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 Tongwei TWMNH-66HD and Tongwei TNC M10-78 Bifacial?
Tongwei TWMNH-66HD has a 30 years power warranty; Tongwei TNC M10-78 Bifacial 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-66HD and Tongwei TNC M10-78 Bifacial bifacial panels?
Tongwei TWMNH-66HD is bifacial (captures light from both faces); Tongwei TNC M10-78 Bifacial is monofacial. Bifacial panels work best on ground mounts or raised structures with a light-coloured surface underneath.

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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.