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660 vs 540 9 of 19 identical Swap Change panels

Waaree WSMD-660 vs Waaree WSMD-540

Waaree WSMD-660
WSMD-660
660 Wp 21.13 % PERC
Open panel page Datasheet PDF
VS
Waaree WSMD-540
WSMD-540
540 Wp 20.98 % PERC
Open panel page Datasheet PDF
The verdict

660 leads on the differences that matter

The largest is rated power: 120 W more power. 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 660 540 Difference
Rated power 660 Wp 540 Wp 120 W more power
Weight 34.5 kg 27.5 kg 7.0 kg lighter
Short-circuit current 17.98 A 13.83 A 4.15 A apart
Module area 3.125 m² 2.574 m² 0.551 m² apart
Open-circuit voltage 46.40 V 49.61 V 3.21 V apart
Temperature coefficient -0.340 %/°C -0.350 %/°C 0.010 %/°C better in heat
Current at max power 17.35 A 12.95 A 4.40 A apart
Cell count 132 144 12 cells apart
Voltage at max power 38.06 V 41.75 V 3.69 V apart
Dimensions 2400x1302x35 mm 2272x1133x35 mm 2400x1302x35 mm vs 2272x1133x35 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
660
21,390 kWh
540
17,501 kWh
Lifetime gap
3,889 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario 660 540
Standard test conditions 25 °C 100.0% of rated power 660 W 540 W
Cool, bright day 40 °C 94.8% of rated power 626 W 512 W
Typical summer roof 55 °C 89.5% of rated power 593 W 483 W
Hot roof 70 °C 84.2% of rated power 559 W 455 W
03

Full specification

Parameter 660 540 Difference
Power and efficiency
Rated power 660 Wp 540 Wp +120 W for 660
Module efficiency 21.13 % 20.98 % Effectively the same
Power density 211.2 Wp/m² 209.8 Wp/m² Effectively the same
Open-circuit voltage 46.40 V 49.61 V 3.21 V apart
Voltage at max power 38.06 V 41.75 V 3.69 V apart
Short-circuit current 17.98 A 13.83 A 4.15 A apart
Current at max power 17.35 A 12.95 A 4.40 A apart
Temperature
Temperature coefficient -0.340 %/°C -0.350 %/°C +0.010 %/°C for 660
Mechanical
Dimensions 2400x1302x35 mm 2272x1133x35 mm 2400x1302x35 mm vs 2272x1133x35 mm
Module area 3.125 m² 2.574 m² 0.551 m² apart
Weight 34.5 kg 27.5 kg -7.0 kg for 540
Weight per kWp 52.3 kg/kWp 50.9 kg/kWp Effectively the same
Warranty and degradation
Product warranty 12 yrs 12 yrs Same
Performance warranty 27 yrs 27 yrs Same
Annual degradation 0.55 %/yr 0.55 %/yr Same
Technology
Cell technology PERC PERC Same
Cell type Monocrystalline Monocrystalline Same
Cell count 132 144 12 cells apart
Bifacial No No Same
04

Against the whole database

14,005 panels
Efficiency
#9,239 vs #9,963
660 leads by 724 places
Power density
#9,251 vs #9,905
660 leads by 654 places
Heat behaviour
#8,778 vs #10,419
660 leads by 1,641 places
Weight
#5,732 vs #4,303
540 leads by 1,429 places
Warranty
#9,667 vs #9,667
Tied - the same position in the database
Overall
#3,874 vs #8,328
660 leads by 4,454 places
05

More useful comparisons

Open the full database
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Waaree WSMD-660 vs Waaree WSMD-665
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Waaree WSMD-660 vs Waaree WSMD-655
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Same series, other bin
Waaree WSMD-660 vs Waaree WSMD-650
3 differences, the largest is module efficiency
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Waaree WSMD-660 vs Waaree WSMD-645
3 differences, the largest is module efficiency
Same series, other bin
Waaree WSMD-660 vs Waaree WSMD-545
10 differences, the largest is rated power
Same series, other bin
Waaree WSMD-660 vs Waaree WSMD-535
12 differences, the largest is rated power
06

Written summary

07

Questions about this pairing

Which panel is better: Waaree WSMD-660 or Waaree WSMD-540?
According to our database: Waaree WSMD-660 has higher module efficiency (21.13% vs 20.98%); Waaree WSMD-660 tolerates heat better (temp coeff -0.340%/°C vs -0.350%/°C). See the full spec comparison and 30-year energy simulation above for a complete picture.
What is the efficiency of Waaree WSMD-660 and Waaree WSMD-540?
Waaree WSMD-660 has a module efficiency of 21.13%, while Waaree WSMD-540 is 20.98%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does Waaree WSMD-660 use vs Waaree WSMD-540?
Waaree WSMD-660 uses PERC cells; Waaree WSMD-540 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 WSMD-660 and Waaree WSMD-540?
Waaree WSMD-660 has a 27 years power warranty; Waaree WSMD-540 has a 27 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.

Shop prices: See 26 Waaree 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.