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M10-78 Bifacial vs G12R-66 Bifacial 10 of 18 identical Swap Change panels

Tongwei TNC M10-78 Bifacial vs Tongwei TNC G12R-66 Bifacial

TNC M10-78 Bifacial
635 Wp 22.70 % TOPCon
Open panel page Datasheet PDF
VS
TNC G12R-66 Bifacial
615 Wp 22.80 % TOPCon
Open panel page Datasheet PDF
The verdict

M10-78 Bifacial leads on the differences that matter

The largest is rated power: 20 W more power. 10 of 18 comparable parameters are identical, with 1 more left out because at least one datasheet does not publish it.

See all 8 differences
How alike are they
10 of 18 comparable
parameters are identical
identical differs not published
01

What actually differs

8 of 18 parameters
Parameter M10-78 Bifacial G12R-66 Bifacial Difference
Rated power 635 Wp 615 Wp 20 W more power
Open-circuit voltage 57.20 V 48.10 V 9.10 V apart
Short-circuit current 13.82 A 15.90 A 2.08 A apart
Module area 2.795 m² 2.701 m² 0.094 m² apart
Voltage at max power 48.05 V 41.35 V 6.70 V apart
Weight 33.8 kg 32.5 kg 1.3 kg lighter
Current at max power 13.22 A 14.88 A 1.66 A apart
Dimensions 2465x1134 mm 2382x1134 mm 2465x1134 mm vs 2382x1134 mm
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 (-0.280 %/°C), so a warmer roof scales both curves by the same factor: the totals fall together and neither panel gains on the other.
M10-78 Bifacial
21,306 kWh
G12R-66 Bifacial
20,634 kWh
Lifetime gap
672 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario M10-78 Bifacial G12R-66 Bifacial
Standard test conditions 25 °C 100.0% of rated power 635 W 615 W
Cool, bright day 40 °C 95.8% of rated power 608 W 589 W
Typical summer roof 55 °C 91.6% of rated power 582 W 563 W
Hot roof 70 °C 87.4% of rated power 555 W 538 W
03

Full specification

Parameter M10-78 Bifacial G12R-66 Bifacial Difference
Power and efficiency
Rated power 635 Wp 615 Wp +20 W for M10-78 Bifacial
Module efficiency 22.70 % 22.80 % Effectively the same
Power density 227.2 Wp/m² 227.7 Wp/m² Effectively the same
Open-circuit voltage 57.20 V 48.10 V 9.10 V apart
Voltage at max power 48.05 V 41.35 V 6.70 V apart
Short-circuit current 13.82 A 15.90 A 2.08 A apart
Current at max power 13.22 A 14.88 A 1.66 A apart
Temperature
Temperature coefficient -0.280 %/°C -0.280 %/°C Same
Mechanical
Dimensions 2465x1134 mm 2382x1134 mm 2465x1134 mm vs 2382x1134 mm
Module area 2.795 m² 2.701 m² 0.094 m² apart
Weight 33.8 kg 32.5 kg -1.3 kg for G12R-66 Bifacial
Weight per kWp 53.2 kg/kWp 52.8 kg/kWp Effectively the same
Warranty and degradation
Product warranty 12 yrs 12 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 - - Neither datasheet publishes this
Bifacial No No Same
04

Against the whole database

14,129 panels
Efficiency
#3,364 vs #2,769
G12R-66 Bifacial leads by 595 places
Power density
#3,309 vs #3,132
G12R-66 Bifacial leads by 177 places
Heat behaviour
#1,347 vs #1,347
Tied - the same position in the database
Weight
#7,136 vs #6,602
G12R-66 Bifacial leads by 534 places
Warranty
#21 vs #21
Tied - the same position in the database
Overall
#2,414 vs #2,915
M10-78 Bifacial leads by 501 places
05

More useful comparisons

Open the full database
Same series, other bin
Tongwei TNC M10-78 Bifacial vs Tongwei THC G12-66 Bifacial
13 differences, the largest is module efficiency
Same series, other bin
Tongwei TNC M10-78 Bifacial vs Tongwei TWMNF-66HD
12 differences, the largest is rated power
Same series, other bin
Tongwei TNC M10-78 Bifacial vs Tongwei TNC G12-66 Monofacial
9 differences, the largest is rated power
Same series, other bin
Tongwei TNC M10-78 Bifacial vs Tongwei TNC G12-66 Bifacial
8 differences, the largest is rated power
Same series, other bin
Tongwei TNC M10-78 Bifacial vs Tongwei TWMNH-66HS
13 differences, the largest is weight
Same series, other bin
Tongwei TNC M10-78 Bifacial vs Tongwei TWMNH-66HD
12 differences, the largest is weight
06

Written summary

07

Questions about this pairing

Which panel is better: Tongwei TNC M10-78 Bifacial or Tongwei TNC G12R-66 Bifacial?
According to our database: Tongwei TNC G12R-66 Bifacial has higher module efficiency (22.80% vs 22.70%). See the full spec comparison and 30-year energy simulation above for a complete picture.
What is the efficiency of Tongwei TNC M10-78 Bifacial and Tongwei TNC G12R-66 Bifacial?
Tongwei TNC M10-78 Bifacial has a module efficiency of 22.70%, while Tongwei TNC G12R-66 Bifacial is 22.80%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does Tongwei TNC M10-78 Bifacial use vs Tongwei TNC G12R-66 Bifacial?
Tongwei TNC M10-78 Bifacial uses TOPCon cells; Tongwei TNC G12R-66 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 TNC M10-78 Bifacial and Tongwei TNC G12R-66 Bifacial?
Tongwei TNC M10-78 Bifacial has a 30 years power warranty; Tongwei TNC G12R-66 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.

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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.