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2.1 640W vs 1.2-280 5 of 19 identical Swap Change panels

Heckert Solar ZEUS 2.1 640W vs Heckert Solar ZEUS 1.2-280

Heckert Solar
ZEUS 2.1 640W
640 Wp 23.70 % TOPCon Bifacial
VS
Heckert Solar ZEUS 1.2-280
Heckert Solar
ZEUS 1.2-280
280 Wp 23.31 % Back Contact Bifacial
The verdict

14 differences, and they point both ways

The largest is rated power: 360 W more power. 5 of 19 comparable parameters are identical.

See all 14 differences
How alike are they
5 of 19 comparable
parameters are identical
identical differs
01

What actually differs

14 of 19 parameters
Parameter 2.1 640W 1.2-280 Difference
Rated power 640 Wp 280 Wp 360 W more power
Weight 32.5 kg 14.3 kg 18.2 kg lighter
Product warranty 12 yrs 30 yrs 18 yrs longer
Temperature coefficient -0.280 %/°C -0.260 %/°C 0.020 %/°C better in heat
Module efficiency 23.70 % 23.31 % 0.39 pp more efficient
Open-circuit voltage 49.75 V 24.11 V 25.64 V apart
Module area 2.701 m² 1.201 m² 1.500 m² apart
Short-circuit current 16.33 A 14.72 A 1.61 A apart
Power density 236.9 Wp/m² 233.1 Wp/m² 3.8 Wp/m² higher
Cell technology TOPCon Back Contact TOPCon vs Back Contact
Voltage at max power 41.38 V 20.49 V 20.89 V apart
Cell count 132 64 68 cells apart
Current at max power 15.47 A 13.67 A 1.80 A apart
Dimensions 2382x1134x30 mm 1560x770x35 mm 2382x1134x30 mm vs 1560x770x35 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
2.1 640W
21,076 kWh
1.2-280
9,221 kWh
Lifetime gap
11,855 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario 2.1 640W 1.2-280
Standard test conditions 25 °C 100.0% of rated power 640 W 280 W
Cool, bright day 40 °C 95.8% of rated power 613 W 269 W
Typical summer roof 55 °C 91.6% of rated power 586 W 258 W
Hot roof 70 °C 87.4% of rated power 559 W 247 W
03

Full specification

Parameter 2.1 640W 1.2-280 Difference
Power and efficiency
Rated power 640 Wp 280 Wp +360 W for 2.1 640W
Module efficiency 23.70 % 23.31 % +0.39 pp for 2.1 640W
Power density 236.9 Wp/m² 233.1 Wp/m² +3.8 Wp/m² for 2.1 640W
Open-circuit voltage 49.75 V 24.11 V 25.64 V apart
Voltage at max power 41.38 V 20.49 V 20.89 V apart
Short-circuit current 16.33 A 14.72 A 1.61 A apart
Current at max power 15.47 A 13.67 A 1.80 A apart
Temperature
Temperature coefficient -0.280 %/°C -0.260 %/°C +0.020 %/°C for 1.2-280
Mechanical
Dimensions 2382x1134x30 mm 1560x770x35 mm 2382x1134x30 mm vs 1560x770x35 mm
Module area 2.701 m² 1.201 m² 1.500 m² apart
Weight 32.5 kg 14.3 kg -18.2 kg for 1.2-280
Weight per kWp 50.8 kg/kWp 51.1 kg/kWp Effectively the same
Warranty and degradation
Product warranty 12 yrs 30 yrs +18 yrs for 1.2-280
Performance warranty 30 yrs 30 yrs Same
Annual degradation 0.45 %/yr 0.45 %/yr Same
Technology
Cell technology TOPCon Back Contact TOPCon vs Back Contact
Cell type Monocrystalline Monocrystalline Same
Cell count 132 64 68 cells apart
Bifacial Yes Yes Same
04

Against the whole database

14,129 panels
Efficiency
#549 vs #1,055
2.1 640W leads by 506 places
Power density
#553 vs #1,136
2.1 640W leads by 583 places
Heat behaviour
#1,347 vs #515
1.2-280 leads by 832 places
Weight
#4,218 vs #4,429
2.1 640W leads by 211 places
Warranty
#21 vs #21
Tied - the same position in the database
Overall
#1,545 vs #9,828
2.1 640W leads by 8,283 places
05

More useful comparisons

Open the full database
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06

Written summary

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07

Questions about this pairing

Which panel is better: Heckert Solar ZEUS 2.1 640W or Heckert Solar ZEUS 1.2-280?
According to our database: Heckert Solar ZEUS 2.1 640 W has higher module efficiency (23.70% vs 23.31%); Heckert Solar ZEUS 1.2-280 tolerates heat better (temp coeff -0.260%/°C vs -0.280%/°C). See the full spec comparison and 30-year energy simulation above for a complete picture.
What is the efficiency of Heckert Solar ZEUS 2.1 640W and Heckert Solar ZEUS 1.2-280?
Heckert Solar ZEUS 2.1 640 W has a module efficiency of 23.70%, while Heckert Solar ZEUS 1.2-280 is 23.31%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does Heckert Solar ZEUS 2.1 640W use vs Heckert Solar ZEUS 1.2-280?
Heckert Solar ZEUS 2.1 640 W uses TOPCon cells; Heckert Solar ZEUS 1.2-280 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 Heckert Solar ZEUS 2.1 640W and Heckert Solar ZEUS 1.2-280?
Heckert Solar ZEUS 2.1 640 W has a 30 years power warranty; Heckert Solar ZEUS 1.2-280 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 Heckert Solar ZEUS 2.1 640W and Heckert Solar ZEUS 1.2-280 bifacial panels?
Both Heckert Solar ZEUS 2.1 640 W and Heckert Solar ZEUS 1.2-280 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 16 Heckert 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.