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645MS vs 655MS 16 of 19 identical Swap Change panels

Canadian Solar CS7N-645MS vs Canadian Solar CS7N-655MS

Canadian Solar CS7N-645MS
CS7N-645MS
645 Wp 20.80 % PERC
Open panel page Datasheet PDF
VS
Canadian Solar CS7N-655MS
CS7N-655MS
655 Wp 21.10 % PERC
Open panel page Datasheet PDF
The verdict

655MS leads on the differences that matter

The largest is module efficiency: 0.30 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
01

What actually differs

3 of 19 parameters
Parameter 645MS 655MS Difference
Module efficiency 20.80 % 21.10 % 0.30 pp more efficient
Power density 207.6 Wp/m² 210.9 Wp/m² 3.2 Wp/m² higher
Rated power 645 Wp 655 Wp 10 W more power
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.
645MS
20,904 kWh
655MS
21,228 kWh
Lifetime gap
324 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario 645MS 655MS
Standard test conditions 25 °C 100.0% of rated power 645 W 655 W
Cool, bright day 40 °C 94.9% of rated power 612 W 622 W
Typical summer roof 55 °C 89.8% of rated power 579 W 588 W
Hot roof 70 °C 84.7% of rated power 546 W 555 W
03

Full specification

Parameter 645MS 655MS Difference
Power and efficiency
Rated power 645 Wp 655 Wp +10 W for 655MS
Module efficiency 20.80 % 21.10 % +0.30 pp for 655MS
Power density 207.6 Wp/m² 210.9 Wp/m² +3.2 Wp/m² for 655MS
Open-circuit voltage 44.80 V 45.20 V Effectively the same
Voltage at max power 37.70 V 38.10 V Effectively the same
Short-circuit current 18.35 A 18.43 A Effectively the same
Current at max power 17.11 A 17.20 A Effectively the same
Temperature
Temperature coefficient -0.340 %/°C -0.340 %/°C Same
Mechanical
Dimensions 2384x1303x35 mm 2384x1303x35 mm Same
Module area 3.106 m² 3.106 m² Same
Weight 33.9 kg 33.9 kg Same
Weight per kWp 52.6 kg/kWp 51.8 kg/kWp Effectively the same
Warranty and degradation
Product warranty 12 yrs 12 yrs Same
Performance warranty 25 yrs 25 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
04

Against the whole database

14,005 panels
Efficiency
#10,457 vs #9,297
655MS leads by 1,160 places
Power density
#10,562 vs #9,459
655MS leads by 1,103 places
Heat behaviour
#8,778 vs #8,778
Tied - the same position in the database
Weight
#6,185 vs #5,121
655MS leads by 1,064 places
Warranty
#9,798 vs #9,798
Tied - the same position in the database
Overall
#5,161 vs #4,457
655MS leads by 704 places
05

More useful comparisons

Open the full database
Same series, other bin
Canadian Solar CS7N-645MS vs Canadian Solar CS7N-675MS
6 differences, the largest is module efficiency
Same series, other bin
Canadian Solar CS7N-645MS vs Canadian Solar CS7N-670MS
5 differences, the largest is module efficiency
Same series, other bin
Canadian Solar CS7N-645MS vs Canadian Solar CS7N-665MS
3 differences, the largest is module efficiency
Same series, other bin
Canadian Solar CS7N-645MS vs Canadian Solar CS7N-660MS
3 differences, the largest is module efficiency
Same series, other bin
Canadian Solar CS7N-645MS vs Canadian Solar CS7N-650MS
The same specification on paper
Same series, other bin
Canadian Solar CS7N-645MS vs Canadian Solar CS7L-615MS
10 differences, the largest is module efficiency
06

Written summary

07

Questions about this pairing

Which panel is better: Canadian Solar CS7N-645MS or Canadian Solar CS7N-655MS?
According to our database: Canadian Solar CS7N-655MS has higher module efficiency (21.10% vs 20.80%). See the full spec comparison and 30-year energy simulation above for a complete picture.
What is the efficiency of Canadian Solar CS7N-645MS and Canadian Solar CS7N-655MS?
Canadian Solar CS7N-645MS has a module efficiency of 20.80%, while Canadian Solar CS7N-655MS is 21.10%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does Canadian Solar CS7N-645MS use vs Canadian Solar CS7N-655MS?
Canadian Solar CS7N-645MS uses PERC cells; Canadian Solar CS7N-655MS 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 Canadian Solar CS7N-645MS and Canadian Solar CS7N-655MS?
Canadian Solar CS7N-645MS has a 25 years power warranty; Canadian Solar CS7N-655MS has a 25 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 39 Canadian Solar 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.