665 vs 645 16 of 19 identical Swap Change panels

Waaree WSMD-665 vs Waaree WSMD-645

Q: Which panel is better: Waaree WSMD-665 or Waaree WSMD-645?

According to our database: Waaree WSMD-665 has higher module efficiency (21.29% vs 20.65%). See the full spec comparison and 30-year energy simulation above for a complete picture.

Q: What is the efficiency of Waaree WSMD-665 and Waaree WSMD-645?

Waaree WSMD-665 has a module efficiency of 21.29%, while Waaree WSMD-645 is 20.65%. Higher efficiency means more electricity from the same roof area - useful when space is limited.

Q: What cell technology does Waaree WSMD-665 use vs Waaree WSMD-645?

Waaree WSMD-665 uses PERC cells; Waaree WSMD-645 uses PERC. Modern n-type technologies (TOPCon, HJT, BC) typically deliver higher efficiency and lower degradation compared to older PERC (p-type) cells.

Q: What is the warranty on Waaree WSMD-665 and Waaree WSMD-645?

Waaree WSMD-665 has a 27 years power warranty; Waaree WSMD-645 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.

WSMD-665

665 Wp 21.29 % PERC

Open panel page Datasheet PDF

WSMD-645

645 Wp 20.65 % PERC

Open panel page Datasheet PDF

The verdict

665 leads on the differences that matter

The largest is module efficiency: 0.64 pp more efficient. 16 of 19 comparable parameters are identical.

See all 3 differences

How alike are they

16 of 19 comparable
parameters are identical

identical differs

What actually differs

3 of 19 parameters

Parameter 665 645 Difference

Module efficiency 21.29 % 20.65 % 0.64 pp more efficient

Power density 212.8 Wp/m² 206.4 Wp/m² 6.4 Wp/m² higher

Rated power 665 Wp 645 Wp 20 W more power

What it means on a roof

Thirty years of production

Each panel's own declared degradation curve, at 1,200 kWh/kWp a year

Cell temperature

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.

665

21,552 kWh

645

20,904 kWh

Lifetime gap

648 kWh

Output when it is hot

Rated power carried across the range a module actually sees

Scenario 665 645

Standard test conditions 25 °C 100.0% of rated power 665 W 645 W

Cool, bright day 40 °C 94.9% of rated power 631 W 612 W

Typical summer roof 55 °C 89.8% of rated power 597 W 579 W

Hot roof 70 °C 84.7% of rated power 563 W 546 W

Full specification

Parameter 665 645 Difference

Power and efficiency

Rated power 665 Wp 645 Wp +20 W for 665

Module efficiency 21.29 % 20.65 % +0.64 pp for 665

Power density 212.8 Wp/m² 206.4 Wp/m² +6.4 Wp/m² for 665

Open-circuit voltage 46.58 V 45.94 V Effectively the same

Voltage at max power 38.10 V 37.87 V Effectively the same

Short-circuit current 18.03 A 17.78 A Effectively the same

Current at max power 17.46 A 17.04 A Effectively the same

Temperature

Temperature coefficient -0.340 %/°C -0.340 %/°C Same

Mechanical

Dimensions 2400x1302x35 mm 2400x1302x35 mm Same

Module area 3.125 m² 3.125 m² Same

Weight 34.5 kg 34.5 kg Same

Weight per kWp 51.9 kg/kWp 53.5 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 132 132 Same

Bifacial No No Same

Against the whole database

14,005 panels

Efficiency

#8,708 vs #11,014

665 leads by 2,306 places

Power density

#8,707 vs #11,023

665 leads by 2,316 places

Heat behaviour

#8,778 vs #8,778

Tied - the same position in the database

Weight

#5,294 vs #7,451

665 leads by 2,157 places

Warranty

#9,667 vs #9,667

Tied - the same position in the database

Overall

#3,494 vs #4,962

665 leads by 1,468 places

More useful comparisons

Open the full database

Same series, other bin

Waaree WSMD-665 vs Waaree WSMD-660

The same specification on paper

Same series, other bin

Waaree WSMD-665 vs Waaree WSMD-655

3 differences, the largest is module efficiency

Same series, other bin

Waaree WSMD-665 vs Waaree WSMD-650

3 differences, the largest is module efficiency

Same series, other bin

Waaree WSMD-665 vs Waaree WSMD-545

10 differences, the largest is rated power

Same series, other bin

Waaree WSMD-665 vs Waaree WSMD-540

12 differences, the largest is rated power

Same series, other bin

Waaree WSMD-665 vs Waaree WSMD-535

12 differences, the largest is rated power

Written summary

Checking cache...

Questions about this pairing

Which panel is better: Waaree WSMD-665 or Waaree WSMD-645?

According to our database: Waaree WSMD-665 has higher module efficiency (21.29% vs 20.65%). See the full spec comparison and 30-year energy simulation above for a complete picture.

What is the efficiency of Waaree WSMD-665 and Waaree WSMD-645?

Waaree WSMD-665 has a module efficiency of 21.29%, while Waaree WSMD-645 is 20.65%. Higher efficiency means more electricity from the same roof area - useful when space is limited.

What cell technology does Waaree WSMD-665 use vs Waaree WSMD-645?

Waaree WSMD-665 uses PERC cells; Waaree WSMD-645 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-665 and Waaree WSMD-645?

Waaree WSMD-665 has a 27 years power warranty; Waaree WSMD-645 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.