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1.2-275 vs 2.1-640 5 of 19 identical Swap Change panels

Heckert Solar ZEUS 1.2-275 vs Heckert Solar ZEUS 2.1-640

Heckert Solar
ZEUS 1.2-275
275 Wp 22.89 % Back Contact Bifacial
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VS
Heckert Solar
ZEUS 2.1-640
640 Wp 23.70 % N-type Bifacial
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The verdict

14 differences, and they point both ways

The largest is module efficiency: 0.81 pp more efficient. 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 1.2-275 2.1-640 Difference
Module efficiency 22.89 % 23.70 % 0.81 pp more efficient
Rated power 275 Wp 640 Wp 365 W more power
Weight 14.3 kg 32.5 kg 18.2 kg lighter
Product warranty 30 yrs 12 yrs 18 yrs longer
Power density 228.9 Wp/m² 236.9 Wp/m² 8.0 Wp/m² higher
Temperature coefficient -0.260 %/°C -0.280 %/°C 0.020 %/°C better in heat
Open-circuit voltage 23.89 V 49.75 V 25.86 V apart
Module area 1.201 m² 2.701 m² 1.500 m² apart
Short-circuit current 14.65 A 16.33 A 1.68 A apart
Cell technology Back Contact N-type Back Contact vs N-type
Voltage at max power 20.36 V 41.38 V 21.02 V apart
Cell count 64 132 68 cells apart
Current at max power 13.51 A 15.47 A 1.96 A apart
Dimensions 1560x770x35 mm 2382x1134x30 mm 1560x770x35 mm vs 2382x1134x30 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
1.2-275
9,056 kWh
2.1-640
21,076 kWh
Lifetime gap
12,020 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario 1.2-275 2.1-640
Standard test conditions 25 °C 100.0% of rated power 275 W 640 W
Cool, bright day 40 °C 95.8% of rated power 264 W 613 W
Typical summer roof 55 °C 91.6% of rated power 254 W 586 W
Hot roof 70 °C 87.4% of rated power 243 W 559 W
03

Full specification

Parameter 1.2-275 2.1-640 Difference
Power and efficiency
Rated power 275 Wp 640 Wp +365 W for 2.1-640
Module efficiency 22.89 % 23.70 % +0.81 pp for 2.1-640
Power density 228.9 Wp/m² 236.9 Wp/m² +8.0 Wp/m² for 2.1-640
Open-circuit voltage 23.89 V 49.75 V 25.86 V apart
Voltage at max power 20.36 V 41.38 V 21.02 V apart
Short-circuit current 14.65 A 16.33 A 1.68 A apart
Current at max power 13.51 A 15.47 A 1.96 A apart
Temperature
Temperature coefficient -0.260 %/°C -0.280 %/°C +0.020 %/°C for 1.2-275
Mechanical
Dimensions 1560x770x35 mm 2382x1134x30 mm 1560x770x35 mm vs 2382x1134x30 mm
Module area 1.201 m² 2.701 m² 1.500 m² apart
Weight 14.3 kg 32.5 kg -18.2 kg for 1.2-275
Weight per kWp 52.0 kg/kWp 50.8 kg/kWp Effectively the same
Warranty and degradation
Product warranty 30 yrs 12 yrs +18 yrs for 1.2-275
Performance warranty 30 yrs 30 yrs Same
Annual degradation 0.45 %/yr 0.45 %/yr Same
Technology
Cell technology Back Contact N-type Back Contact vs N-type
Cell type Monocrystalline Monocrystalline Same
Cell count 64 132 68 cells apart
Bifacial Yes Yes Same
04

Against the whole database

13,953 panels
Efficiency
#2,490 vs #511
2.1-640 leads by 1,979 places
Power density
#2,404 vs #515
2.1-640 leads by 1,889 places
Heat behaviour
#511 vs #1,290
1.2-275 leads by 779 places
Weight
#5,386 vs #4,174
2.1-640 leads by 1,212 places
Warranty
#21 vs #21
Tied - the same position in the database
Overall
#10,137 vs #1,515
2.1-640 leads by 8,622 places
05

More useful comparisons

Open the full database
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Heckert Solar ZEUS 1.2-275 vs Heckert Solar ZEUS 1.2 FullBlack 280W
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Heckert Solar ZEUS 1.2-275 vs Heckert Solar ZEUS 1.2-280
2 differences, the largest is module efficiency
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Heckert Solar ZEUS 1.2-275 vs Heckert Solar ZEUS 1.2 FullBlack 275W
The same specification on paper
06

Written summary

07

Questions about this pairing

Which panel is better: Heckert Solar ZEUS 1.2-275 or Heckert Solar ZEUS 2.1-640?
According to our database: Heckert Solar ZEUS 2.1-640 has higher module efficiency (23.70% vs 22.89%); Heckert Solar ZEUS 1.2-275 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 1.2-275 and Heckert Solar ZEUS 2.1-640?
Heckert Solar ZEUS 1.2-275 has a module efficiency of 22.89%, while Heckert Solar ZEUS 2.1-640 is 23.70%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does Heckert Solar ZEUS 1.2-275 use vs Heckert Solar ZEUS 2.1-640?
Heckert Solar ZEUS 1.2-275 uses Back Contact cells; Heckert Solar ZEUS 2.1-640 uses N-type. 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 1.2-275 and Heckert Solar ZEUS 2.1-640?
Heckert Solar ZEUS 1.2-275 has a 30 years power warranty; Heckert Solar ZEUS 2.1-640 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 1.2-275 and Heckert Solar ZEUS 2.1-640 bifacial panels?
Both Heckert Solar ZEUS 1.2-275 and Heckert Solar ZEUS 2.1-640 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.