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Gokin GK-4-78HGBD-780M

GK-4-78HGBD-780M

780 Wp Back Contact Bifacial 70%
ComparePV verdict

Efficiency leader, no clear weak spot

Rank 15 of 14,005
Compare panels Datasheet PDF
Power (Wp)
780
Strong · top 1%
Efficiency (%)
24.30
Strong · top 1%
Density (Wp/m²)
242.8
Strong · top 2%
Temp (%/°C)
-0.260
Typical · median -0.290
Weight (kg)
38.7
Strong · top 12%
Warranty (yrs)
30
Typical · median 30 yrs

The Gokin GK-4-78HGBD series represents a breakthrough in efficiency thanks to the use of N-type TOPCon technology, which eliminates the problem of light-induced degradation and guarantees stable operation for decades. The use of bifacial dual glass construction allows for efficient energy harvesting not only directly from the sun but also from radiation reflected from the ground, which significantly increases the total annual energy yield. These modules solve the problem of limited installation space by offering high power density while maintaining exceptional resistance to extreme weather conditions, such as strong winds or snow loads. A distinguishing feature of the series is its excellent temperature coefficient, ensuring that the panels maintain high efficiency even on hot days when traditional cells lose performance. This solution is primarily dedicated to large-scale photovoltaic farms and demanding business installations where maximum return on investment and component durability are key. The Gokin GK-4-78HGBD stands out from the competition through precise optimization of the production process, which translates into minimal losses at cell interconnections and better performance characteristics in low-light conditions. By choosing this series, investors gain technological certainty backed by an innovative 78-cell structure that redefines the standards of modern solar energy.

Ranking

948 panels in the 680-880 W band, all technologies
Metric This panel Median Position in segment Overall rank
Module efficiency 24.30% 22.90% Strong · top 1% 131
Power density 242.8 228.6 Strong · top 2% 138
Temperature coefficient -0.260 -0.290 Typical 511
Weight per kWp 49.6 53.4 Strong · top 12% 3,161
Performance warranty 30 yrs 30 yrs Typical 21
Colour key Strong - top 25% Typical - middle 50% Weak - bottom 25%

Signals from the data

8 positive · 3 caution
Best for

Utility-scale, commercial and hot-climate.

Strengths
24.30% module efficiency

Top 1% of the 680-880 W band, against a median of 22.90%. Ranked 131st in the whole database.

242.8 watts per square metre

Top 2% of the 680-880 W band, against a median of 228.6. Ranked 138th in the whole database.

49.6 kg per kWp

Top 12% of the 680-880 W band, against a median of 53.4.

What owners get
Back Contact Technology with Zero Front-Side Shading

Relocating all electrical contacts to the rear of the cell eliminates losses caused by front-grid shading. Combined with N-type architecture, this delivers module efficiency of 23.7–24.3% — surpassing peers such as Sunplus Hi-Max (24.1%) and Gamko GKA210N132 (24.14%) at a significantly higher unit power output of up to 780 Wp.

Class A Fire Rating (Dual Glass)

The module is certified Class A fire-resistant by virtue of its dual-glass construction, a requirement for rooftop installations with a pitch >18° near adjacent buildings and for the majority of European utility-scale tenders. Many competitors in this power class offer only Class C.

Exceptional Mechanical Strength

A certified static front-side load rating of 5,400 Pa (equivalent to ~550 kg/m²) and hail resistance of 25 mm diameter at 23 m/s meet the highest IEC requirements for ground-mounted systems in climatic zones subject to extreme weather conditions.

30-Year Linear Power Output Warranty

The manufacturer provides a 30-year linear power warranty, placing the series at the upper end of the current market standard. Comparable peers Sunplus Hi-Max and Gamko GKA210N132 do not publicly document equivalent warranty terms for the 750 Wp+ class, giving Gokin a competitive advantage in LCOE calculations for institutional investors.

Confirmed Technology Partnership with AIKO

In April 2026, Gokin and AIKO — a recognized leader in BC cell technology — announced an expanded strategic agreement covering BC commercialization. This provides Gokin with access to advanced cell know-how and validates the technological credibility of the GK-4-78HGBD series in the utility-scale market.

Trade-offs
No BNEF Tier 1 Status (Bankability Gap)

Gokin Solar does not appear on the BloombergNEF Tier 1 list, creating significant barriers to project finance for PV plants above 10 MW. This is a critical obstacle for the series' primary target segment — large-scale solar farms — where most EPCs and lenders mandate Tier-1 bankability as a contractual prerequisite.

Efficiency Gap vs. AIKO Stellar 2N+78

The closest direct comparable, AIKO Stellar 2N+78, delivers 25.1% efficiency and 805 Wp peak power versus Gokin's 24.3% / 780 Wp — a gap of 0.8 percentage points and 25 Wp. At the 10 MWp scale, this translates to approximately 312–400 additional modules required to achieve the same nameplate capacity, representing a measurable cost for investors optimizing land utilization.

75% Bifaciality Factor — Low for BC Technology

The declared bifaciality factor of ≤75% is on par with standard TOPCon modules, while advanced ABC cells from competitors (e.g., AIKO) achieve 85%+. In ground-mounted installations with high-albedo ground cover or on white-rooftop systems, this difference can result in 3–5% lower annual rear-side energy yield.

Notes from the database
  • Efficiency of 24.3% matches the Back Contact 750-800W median
  • At 242.8 W/m² power density, roof space requirements are typical for Back Contact 750-800W panels
  • Temperature coefficient of -0.26%/°C matches the Back Contact 750-800W median
  • At 38.7 kg, this panel is 1.1 kg lighter than Back Contact 750-800W median (39.8 kg) - easier handling during installation
  • 70% bifaciality enables rear-side power generation, boosting yield by 4-10% on reflective surfaces

Specifications

Open datasheet PDF
Nominal power (Pmax) 780 Wp Nameplate at 1000 W/m², 25 °C
Module efficiency 24.30 % Strong Segment median 22.90%
Vmpp · Impp 48.97 V · 15.93 A Operating point at max power
Voc · Isc 58.92 V · 16.78 A Sizes the string length
Max system voltage 1500 V Longer strings than 1000 V modules
Dimensions 2465×1303×33 mm · 3.21 m² of roof
Weight 38.7 kg Strong Strong · top 12%
Cells 156 · Back Contact Monocrystalline
Bifaciality 70 % Rear output as a share of front
Coefficient Pmax -0.260 %/°C Typical median -0.290 of its segment
Coefficient Voc · Isc -0.220 · 0.050 %/°C
NOCT 45 °C At 800 W/m², 20 °C ambient
Product warranty 15 years Hardware defects only
Performance warranty 30 years Typical median 30 yrs · median 30 yrs
End-of-warranty output 88.8 % Equals 693 W guaranteed
Degradation 1.00 → 0.35 % First year, then annual

Datasheet charts

Open datasheet PDF

Measured curves published by Gokin in this model's datasheet. A chart carrying a wattage was measured on that variant alone - only the ones that describe 780 Wp appear here. The rest cover the whole series.

Simulations

Live - change any input
Lifetime output & value
30 years at 1200 kWh/kWp/year and €0.50 per kWh
Power in year 30
-
Lifetime energy
-
Energy value
-
With bifacial gain
-

Degradation from this panel's own datasheet figures. No inverter, soiling or shading losses.

Heat losses
-0.260 %/°C against a segment median of -0.290
-
Bifacial gain
Rear gain over light concrete: -
-

Model: bifaciality × albedo × 0.6 view factor. A first-order estimate, not a yield simulation.

Filter these
Size
Panel Power Eff. Temp. Weight Difference
Gokin GK-4-78HGBD-780M 780 W 24.30% -0.260 38.7 kg You are here
AIKO-A805-GRH78Dw 805 W 25.10% -0.260 39.8 kg +25 W, heavier, +0.8 pp
AIKO-A800-GRH78Dw 800 W 24.90% -0.260 39.8 kg +20 W, heavier, +0.6 pp
AIKO-A795-GRH78Dw 795 W 24.80% -0.260 39.8 kg +15 W, heavier, +0.5 pp
AIKO-A790-GRH78Dw 790 W 24.60% -0.260 39.8 kg +10 W, heavier, +0.3 pp
TSM-NEG21C.20Q-760 760 W 24.50% -0.260 38.3 kg -20 W
AIKO-A785-GRH78Dw 785 W 24.40% -0.260 39.8 kg Heavier
AIKO-A780-GRH78Dw 780 W 24.30% -0.260 39.8 kg Heavier
JT755SLk(B) 755 W 24.30% -0.240 36.4 kg -25 W, cooler, lighter
TSM-NEG21C.20Q-755 755 W 24.30% -0.260 38.3 kg -25 W
GK-4-78HGBD-760M 760 W 23.70% -0.260 38.7 kg -20 W, -0.6 pp
GK-4-78HGBD-765M 765 W 23.80% -0.260 38.7 kg -15 W, -0.5 pp
GK-4-78HGBD-770M 770 W 24.00% -0.260 38.7 kg -10 W, -0.3 pp
GK-4-78HGBD-775M 775 W 24.10% -0.260 38.7 kg Very close match

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Common questions

6 answered
What is Back Contact technology in the Gokin GK-4-78HGBD panels and how does it differ from conventional cells?
In Back Contact technology, all electrical contacts are relocated to the rear side of the cell, leaving the entire front surface fully photoelectrically active. The Gokin GK-4-78HGBD achieves module efficiency of 23.7–24.3% by eliminating power losses caused by shading from metallic busbars. This is one of the key reasons the series generates more energy per square meter than typical TOPCon or PERC modules.
How much additional energy does the bifacial dual-glass design of the Gokin GK-4-78HGBD series produce?
The GK-4-78HGBD module features a bifaciality factor of up to 75%, meaning the rear glass can capture up to 75% of the energy relative to the front side. In practice, installations over high-albedo surfaces — such as concrete, light-colored membranes, or gravel — yield a real-world energy gain of approximately 5–15% per year compared to a monofacial panel of the same rated power.
What warranty applies to the Gokin GK-4-78HGBD panels and what exactly does it cover?
The manufacturer provides a 15-year product warranty covering material and workmanship defects, along with a 30-year linear power output warranty. This means the panel's output will remain no lower than the values specified in the degradation schedule for three full decades. The dual-glass construction additionally protects the cells against moisture ingress, further reinforcing the module's real-world durability beyond the stated warranty terms.
Does the Gokin GK-4-78HGBD series perform well on hot days and under overcast conditions?
Yes. Back Contact technology exhibits a more favorable temperature coefficient than standard PERC cells, so the panel loses less power at elevated operating temperatures. The module operates across a temperature range of -40°C to +85°C. The bifacial cell architecture also improves energy yield under diffuse irradiance, which is particularly relevant under the frequently overcast sky conditions typical of the Polish climate.
What type of installation is the Gokin GK-4-78HGBD series designed for — is it suitable for a single-family home?
The GK-4-78HGBD series is designed primarily for utility-scale solar farms and commercial & industrial (C&I) installations. The module weighs 38.7 kg and measures 2,465 × 1,303 mm, which makes handling and mounting on a typical residential pitched roof impractical. Residential prosumers would be considerably better served by smaller and lighter panels from Gokin's portfolio or from other manufacturers.
What mechanical loads can the Gokin GK-4-78HGBD panel withstand — will it handle a Polish winter and high winds?
The module is certified for a static mechanical load of 5,400 Pa on the front side and 2,400 Pa on the rear side, corresponding to resistance against extreme snow accumulation and high wind pressures. It has also passed hail impact testing: ice balls 25 mm in diameter at a velocity of 23 m/s cause no damage. For Polish climatic conditions, these specifications provide a substantial safety margin well above the requirements of applicable building standards.
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