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765M vs 775M 16 of 19 identical Swap Change panels

Gokin GK-4-78HGBD-765M vs Gokin GK-4-78HGBD-775M

Gokin GK-4-78HGBD-765M
Gokin
GK-4-78HGBD-765M
765 Wp 23.80 % Back Contact Bifacial
Open panel page Datasheet PDF
VS
Gokin GK-4-78HGBD-775M
Gokin
GK-4-78HGBD-775M
775 Wp 24.10 % Back Contact Bifacial
Open panel page Datasheet PDF
The verdict

775M leads on the differences that matter

The largest is module efficiency: 0.30 pp more efficient. 16 of 19 comparable parameters are identical.

See all 3 differences
How alike are they
16 of 19 comparable
parameters are identical
identical differs
01

What actually differs

3 of 19 parameters
Parameter 765M 775M Difference
Module efficiency 23.80 % 24.10 % 0.30 pp more efficient
Power density 238.2 Wp/m² 241.3 Wp/m² 3.1 Wp/m² higher
Rated power 765 Wp 775 Wp 10 W more power
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 (-0.260 %/°C), so a warmer roof scales both curves by the same factor: the totals fall together and neither panel gains on the other.
765M
25,867 kWh
775M
26,205 kWh
Lifetime gap
338 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario 765M 775M
Standard test conditions 25 °C 100.0% of rated power 765 W 775 W
Cool, bright day 40 °C 96.1% of rated power 735 W 745 W
Typical summer roof 55 °C 92.2% of rated power 705 W 715 W
Hot roof 70 °C 88.3% of rated power 675 W 684 W
03

Full specification

Parameter 765M 775M Difference
Power and efficiency
Rated power 765 Wp 775 Wp +10 W for 775M
Module efficiency 23.80 % 24.10 % +0.30 pp for 775M
Power density 238.2 Wp/m² 241.3 Wp/m² +3.1 Wp/m² for 775M
Open-circuit voltage 58.62 V 58.82 V Effectively the same
Voltage at max power 48.67 V 48.87 V Effectively the same
Short-circuit current 16.57 A 16.71 A Effectively the same
Current at max power 15.72 A 15.86 A Effectively the same
Temperature
Temperature coefficient -0.260 %/°C -0.260 %/°C Same
Mechanical
Dimensions 2465x1303x33 mm 2465x1303x33 mm Same
Module area 3.212 m² 3.212 m² Same
Weight 38.7 kg 38.7 kg Same
Weight per kWp 50.6 kg/kWp 49.9 kg/kWp Effectively the same
Warranty and degradation
Product warranty 15 yrs 15 yrs Same
Performance warranty 30 yrs 30 yrs Same
Annual degradation 0.35 %/yr 0.35 %/yr Same
Technology
Cell technology Back Contact Back Contact Same
Cell type Monocrystalline Monocrystalline Same
Cell count 156 156 Same
Bifacial Yes Yes Same
04

Against the whole database

14,005 panels
Efficiency
#433 vs #219
775M leads by 214 places
Power density
#452 vs #227
775M leads by 225 places
Heat behaviour
#511 vs #511
Tied - the same position in the database
Weight
#4,013 vs #3,297
775M leads by 716 places
Warranty
#21 vs #21
Tied - the same position in the database
Overall
#67 vs #29
775M leads by 38 places
05

More useful comparisons

Open the full database
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Gokin GK-4-78HGBD-765M vs Gokin GK-4-78HGBD-780M
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Gokin GK-4-78HGBD-765M vs Gokin GK-4-78HGBD-770M
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Gokin GK-4-78HGBD-765M vs Gokin GK-4-78HGBD-760M
The same specification on paper
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Gokin GK-4-78HGBD-765M vs Gokin GK-5-60HG-540M
13 differences, the largest is rated power
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Gokin GK-4-78HGBD-765M vs Gokin GK-5-60HG-535M
13 differences, the largest is rated power
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Gokin GK-4-78HGBD-765M vs Gokin GK-5-60HG-530M
11 differences, the largest is rated power
06

Written summary

07

Questions about this pairing

Which panel is better: Gokin GK-4-78HGBD-765M or Gokin GK-4-78HGBD-775M?
According to our database: Gokin GK-4-78HGBD-775M has higher module efficiency (24.10% vs 23.80%). See the full spec comparison and 30-year energy simulation above for a complete picture.
What is the efficiency of Gokin GK-4-78HGBD-765M and Gokin GK-4-78HGBD-775M?
Gokin GK-4-78HGBD-765M has a module efficiency of 23.80%, while Gokin GK-4-78HGBD-775M is 24.10%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does Gokin GK-4-78HGBD-765M use vs Gokin GK-4-78HGBD-775M?
Gokin GK-4-78HGBD-765M uses Back Contact cells; Gokin GK-4-78HGBD-775M uses Back Contact. 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 Gokin GK-4-78HGBD-765M and Gokin GK-4-78HGBD-775M?
Gokin GK-4-78HGBD-765M has a 30 years power warranty; Gokin GK-4-78HGBD-775M 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 Gokin GK-4-78HGBD-765M and Gokin GK-4-78HGBD-775M bifacial panels?
Both Gokin GK-4-78HGBD-765M and Gokin GK-4-78HGBD-775M 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.