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540 vs 665 7 of 19 identical Swap Change panels

Waaree WSMD-540 vs Waaree WSMD-665

Waaree WSMD-540
WSMD-540
540 Wp 20.98 % PERC
Open panel page Datasheet PDF
VS
Waaree WSMD-665
WSMD-665
665 Wp 21.29 % PERC
Open panel page Datasheet PDF
The verdict

665 leads on the differences that matter

The largest is rated power: 125 W more power. 7 of 19 comparable parameters are identical.

See all 12 differences
How alike are they
7 of 19 comparable
parameters are identical
identical differs
01

What actually differs

12 of 19 parameters
Parameter 540 665 Difference
Rated power 540 Wp 665 Wp 125 W more power
Weight 27.5 kg 34.5 kg 7.0 kg lighter
Short-circuit current 13.83 A 18.03 A 4.20 A apart
Module area 2.574 m² 3.125 m² 0.551 m² apart
Module efficiency 20.98 % 21.29 % 0.31 pp more efficient
Open-circuit voltage 49.61 V 46.58 V 3.03 V apart
Temperature coefficient -0.350 %/°C -0.340 %/°C 0.010 %/°C better in heat
Power density 209.8 Wp/m² 212.8 Wp/m² 3.0 Wp/m² higher
Current at max power 12.95 A 17.46 A 4.51 A apart
Cell count 144 132 12 cells apart
Voltage at max power 41.75 V 38.10 V 3.65 V apart
Dimensions 2272x1133x35 mm 2400x1302x35 mm 2272x1133x35 mm vs 2400x1302x35 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
540
17,501 kWh
665
21,552 kWh
Lifetime gap
4,051 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario 540 665
Standard test conditions 25 °C 100.0% of rated power 540 W 665 W
Cool, bright day 40 °C 94.8% of rated power 512 W 631 W
Typical summer roof 55 °C 89.5% of rated power 483 W 597 W
Hot roof 70 °C 84.2% of rated power 455 W 563 W
03

Full specification

Parameter 540 665 Difference
Power and efficiency
Rated power 540 Wp 665 Wp +125 W for 665
Module efficiency 20.98 % 21.29 % +0.31 pp for 665
Power density 209.8 Wp/m² 212.8 Wp/m² +3.0 Wp/m² for 665
Open-circuit voltage 49.61 V 46.58 V 3.03 V apart
Voltage at max power 41.75 V 38.10 V 3.65 V apart
Short-circuit current 13.83 A 18.03 A 4.20 A apart
Current at max power 12.95 A 17.46 A 4.51 A apart
Temperature
Temperature coefficient -0.350 %/°C -0.340 %/°C +0.010 %/°C for 665
Mechanical
Dimensions 2272x1133x35 mm 2400x1302x35 mm 2272x1133x35 mm vs 2400x1302x35 mm
Module area 2.574 m² 3.125 m² 0.551 m² apart
Weight 27.5 kg 34.5 kg -7.0 kg for 540
Weight per kWp 50.9 kg/kWp 51.9 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 144 132 12 cells apart
Bifacial No No Same
04

Against the whole database

14,005 panels
Efficiency
#9,963 vs #8,708
665 leads by 1,255 places
Power density
#9,905 vs #8,707
665 leads by 1,198 places
Heat behaviour
#10,419 vs #8,778
665 leads by 1,641 places
Weight
#4,303 vs #5,294
540 leads by 991 places
Warranty
#9,667 vs #9,667
Tied - the same position in the database
Overall
#8,328 vs #3,494
665 leads by 4,834 places
05

More useful comparisons

Open the full database
Same series, other bin
Waaree WSMD-540 vs Waaree WSMD-660
10 differences, the largest is rated power
Same series, other bin
Waaree WSMD-540 vs Waaree WSMD-655
10 differences, the largest is rated power
Same series, other bin
Waaree WSMD-540 vs Waaree WSMD-650
11 differences, the largest is rated power
Same series, other bin
Waaree WSMD-540 vs Waaree WSMD-645
13 differences, the largest is rated power
Same series, other bin
Waaree WSMD-540 vs Waaree WSMD-545
The same specification on paper
Same series, other bin
Waaree WSMD-540 vs Waaree WSMD-535
One difference: module efficiency
06

Written summary

07

Questions about this pairing

Which panel is better: Waaree WSMD-540 or Waaree WSMD-665?
According to our database: Waaree WSMD-665 has higher module efficiency (21.29% vs 20.98%); Waaree WSMD-665 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-540 and Waaree WSMD-665?
Waaree WSMD-540 has a module efficiency of 20.98%, while Waaree WSMD-665 is 21.29%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does Waaree WSMD-540 use vs Waaree WSMD-665?
Waaree WSMD-540 uses PERC cells; Waaree WSMD-665 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-540 and Waaree WSMD-665?
Waaree WSMD-540 has a 27 years power warranty; Waaree WSMD-665 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.