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68-660 vs 66-580 9 of 19 identical Swap Change panels

Waaree Bi-68-660 vs Waaree Bi-66-580

Waaree Bi-68-660
Bi-68-660
660 Wp 21.13 % PERC Bifacial
VS
Waaree Bi-66-580
Bi-66-580
580 Wp 20.35 % PERC Bifacial
The verdict

68-660 leads on the differences that matter

The largest is module efficiency: 0.78 pp more efficient. 9 of 19 comparable parameters are identical.

See all 10 differences
How alike are they
9 of 19 comparable
parameters are identical
identical differs
01

What actually differs

10 of 19 parameters
Parameter 68-660 66-580 Difference
Module efficiency 21.13 % 20.35 % 0.78 pp more efficient
Rated power 660 Wp 580 Wp 80 W more power
Weight 39.0 kg 35.5 kg 3.5 kg lighter
Power density 211.2 Wp/m² 203.4 Wp/m² 7.8 Wp/m² higher
Open-circuit voltage 46.40 V 41.56 V 4.84 V apart
Module area 3.125 m² 2.851 m² 0.273 m² apart
Cell count 132 120 12 cells apart
Voltage at max power 38.06 V 34.21 V 3.85 V apart
Weight per kWp 59.1 kg/kWp 61.2 kg/kWp 2.1 kg/kWp lighter
Dimensions 2400x1302x35 mm 2190x1302x35 mm 2400x1302x35 mm vs 2190x1302x35 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 (-0.340 %/°C), so a warmer roof scales both curves by the same factor: the totals fall together and neither panel gains on the other.
68-660
21,390 kWh
66-580
18,797 kWh
Lifetime gap
2,593 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario 68-660 66-580
Standard test conditions 25 °C 100.0% of rated power 660 W 580 W
Cool, bright day 40 °C 94.9% of rated power 626 W 550 W
Typical summer roof 55 °C 89.8% of rated power 593 W 521 W
Hot roof 70 °C 84.7% of rated power 559 W 491 W
03

Full specification

Parameter 68-660 66-580 Difference
Power and efficiency
Rated power 660 Wp 580 Wp +80 W for 68-660
Module efficiency 21.13 % 20.35 % +0.78 pp for 68-660
Power density 211.2 Wp/m² 203.4 Wp/m² +7.8 Wp/m² for 68-660
Open-circuit voltage 46.40 V 41.56 V 4.84 V apart
Voltage at max power 38.06 V 34.21 V 3.85 V apart
Short-circuit current 17.98 A 17.73 A Effectively the same
Current at max power 17.35 A 16.96 A Effectively the same
Temperature
Temperature coefficient -0.340 %/°C -0.340 %/°C Same
Mechanical
Dimensions 2400x1302x35 mm 2190x1302x35 mm 2400x1302x35 mm vs 2190x1302x35 mm
Module area 3.125 m² 2.851 m² 0.273 m² apart
Weight 39.0 kg 35.5 kg -3.5 kg for 66-580
Weight per kWp 59.1 kg/kWp 61.2 kg/kWp -2.1 kg/kWp for 68-660
Warranty and degradation
Product warranty 12 yrs 12 yrs Same
Performance warranty 30 yrs 30 yrs Same
Annual degradation 0.55 %/yr 0.55 %/yr Same
Technology
Cell technology PERC PERC Same
Cell type Monocrystalline Monocrystalline Same
Cell count 132 120 12 cells apart
Bifacial Yes Yes Same
04

Against the whole database

14,005 panels
Efficiency
#9,239 vs #11,718
68-660 leads by 2,479 places
Power density
#9,251 vs #11,699
68-660 leads by 2,448 places
Heat behaviour
#8,778 vs #8,778
Tied - the same position in the database
Weight
#12,010 vs #12,612
68-660 leads by 602 places
Warranty
#21 vs #21
Tied - the same position in the database
Overall
#3,318 vs #7,089
68-660 leads by 3,771 places
05

More useful comparisons

Open the full database
Same series, other bin
Waaree Bi-68-660 vs Waaree Bi-68-665
The same specification on paper
Same series, other bin
Waaree Bi-68-660 vs Waaree Bi-68-655
The same specification on paper
Same series, other bin
Waaree Bi-68-660 vs Waaree Bi-68-650
3 differences, the largest is module efficiency
Same series, other bin
Waaree Bi-68-660 vs Waaree Bi-68-645
3 differences, the largest is module efficiency
Same series, other bin
Waaree Bi-68-660 vs Waaree Bi-66-600
7 differences, the largest is rated power
Same series, other bin
Waaree Bi-68-660 vs Waaree Bi-66-595
8 differences, the largest is rated power
06

Written summary

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07

Questions about this pairing

Which panel is better: Waaree Bi-68-660 or Waaree Bi-66-580?
According to our database: Waaree Bi-68-660 has higher module efficiency (21.13% vs 20.35%). See the full spec comparison and 30-year energy simulation above for a complete picture.
What is the efficiency of Waaree Bi-68-660 and Waaree Bi-66-580?
Waaree Bi-68-660 has a module efficiency of 21.13%, while Waaree Bi-66-580 is 20.35%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does Waaree Bi-68-660 use vs Waaree Bi-66-580?
Waaree Bi-68-660 uses PERC cells; Waaree Bi-66-580 uses PERC. 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 Waaree Bi-68-660 and Waaree Bi-66-580?
Waaree Bi-68-660 has a 30 years power warranty; Waaree Bi-66-580 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 Waaree Bi-68-660 and Waaree Bi-66-580 bifacial panels?
Both Waaree Bi-68-660 and Waaree Bi-66-580 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.