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645 vs 540 6 of 19 identical Swap Change panels

Waaree WSMD-645 vs Waaree WSMD-540

Waaree WSMD-645
WSMD-645
645 Wp 20.65 % PERC
Open panel page Datasheet PDF
VS
Waaree WSMD-540
WSMD-540
540 Wp 20.98 % PERC
Open panel page Datasheet PDF
The verdict

13 differences, and they point both ways

The largest is rated power: 105 W more power. 6 of 19 comparable parameters are identical.

See all 13 differences
How alike are they
6 of 19 comparable
parameters are identical
identical differs
01

What actually differs

13 of 19 parameters
Parameter 645 540 Difference
Rated power 645 Wp 540 Wp 105 W more power
Weight 34.5 kg 27.5 kg 7.0 kg lighter
Module efficiency 20.65 % 20.98 % 0.33 pp more efficient
Short-circuit current 17.78 A 13.83 A 3.95 A apart
Module area 3.125 m² 2.574 m² 0.551 m² apart
Open-circuit voltage 45.94 V 49.61 V 3.67 V apart
Temperature coefficient -0.340 %/°C -0.350 %/°C 0.010 %/°C better in heat
Power density 206.4 Wp/m² 209.8 Wp/m² 3.4 Wp/m² higher
Current at max power 17.04 A 12.95 A 4.09 A apart
Cell count 132 144 12 cells apart
Voltage at max power 37.87 V 41.75 V 3.88 V apart
Weight per kWp 53.5 kg/kWp 50.9 kg/kWp 2.6 kg/kWp lighter
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
645
20,904 kWh
540
17,501 kWh
Lifetime gap
3,403 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario 645 540
Standard test conditions 25 °C 100.0% of rated power 645 W 540 W
Cool, bright day 40 °C 94.8% of rated power 612 W 512 W
Typical summer roof 55 °C 89.5% of rated power 579 W 483 W
Hot roof 70 °C 84.2% of rated power 546 W 455 W
03

Full specification

Parameter 645 540 Difference
Power and efficiency
Rated power 645 Wp 540 Wp +105 W for 645
Module efficiency 20.65 % 20.98 % +0.33 pp for 540
Power density 206.4 Wp/m² 209.8 Wp/m² +3.4 Wp/m² for 540
Open-circuit voltage 45.94 V 49.61 V 3.67 V apart
Voltage at max power 37.87 V 41.75 V 3.88 V apart
Short-circuit current 17.78 A 13.83 A 3.95 A apart
Current at max power 17.04 A 12.95 A 4.09 A apart
Temperature
Temperature coefficient -0.340 %/°C -0.350 %/°C +0.010 %/°C for 645
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 53.5 kg/kWp 50.9 kg/kWp -2.6 kg/kWp for 540
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
#11,014 vs #9,963
540 leads by 1,051 places
Power density
#11,023 vs #9,905
540 leads by 1,118 places
Heat behaviour
#8,778 vs #10,419
645 leads by 1,641 places
Weight
#7,451 vs #4,303
540 leads by 3,148 places
Warranty
#9,667 vs #9,667
Tied - the same position in the database
Overall
#4,962 vs #8,328
645 leads by 3,366 places
05

More useful comparisons

Open the full database
Same series, other bin
Waaree WSMD-645 vs Waaree WSMD-665
3 differences, the largest is module efficiency
Same series, other bin
Waaree WSMD-645 vs Waaree WSMD-660
3 differences, the largest is module efficiency
Same series, other bin
Waaree WSMD-645 vs Waaree WSMD-655
3 differences, the largest is module efficiency
Same series, other bin
Waaree WSMD-645 vs Waaree WSMD-650
The same specification on paper
Same series, other bin
Waaree WSMD-645 vs Waaree WSMD-545
13 differences, the largest is rated power
Same series, other bin
Waaree WSMD-645 vs Waaree WSMD-535
11 differences, the largest is rated power
06

Written summary

07

Questions about this pairing

Which panel is better: Waaree WSMD-645 or Waaree WSMD-540?
According to our database: Waaree WSMD-540 has higher module efficiency (20.98% vs 20.65%); Waaree WSMD-645 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-645 and Waaree WSMD-540?
Waaree WSMD-645 has a module efficiency of 20.65%, 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-645 use vs Waaree WSMD-540?
Waaree WSMD-645 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-645 and Waaree WSMD-540?
Waaree WSMD-645 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.