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640 XL vs 380 BK 3 of 19 identical Swap Change panels

Silfab SIL-640 XL vs Silfab SIL-380 BK

Silfab
SIL-640 XL
640 Wp 22.92 % N-type Bifacial
Open panel page Datasheet PDF
VS
Silfab
SIL-380 BK
380 Wp 21.40 % PERC
Open panel page Datasheet PDF
The verdict

640 XL leads on the differences that matter

The largest is module efficiency: 1.52 pp more efficient. 3 of 19 comparable parameters are identical.

See all 16 differences
How alike are they
3 of 19 comparable
parameters are identical
identical differs
01

What actually differs

16 of 19 parameters
Parameter 640 XL 380 BK Difference
Module efficiency 22.92 % 21.40 % 1.52 pp more efficient
Temperature coefficient -0.290 %/°C -0.377 %/°C 0.087 %/°C better in heat
Rated power 640 Wp 380 Wp 260 W more power
Power density 229.2 Wp/m² 213.8 Wp/m² 15.3 Wp/m² higher
Annual degradation 0.30 %/yr 0.50 %/yr 0.20 %/yr slower
Weight 29.5 kg 19.0 kg 10.5 kg lighter
Open-circuit voltage 57.76 V 45.13 V 12.63 V apart
Short-circuit current 13.76 A 10.50 A 3.26 A apart
Module area 2.793 m² 1.777 m² 1.016 m² apart
Weight per kWp 46.1 kg/kWp 50.0 kg/kWp 3.9 kg/kWp lighter
Cell technology N-type PERC N-type vs PERC
Voltage at max power 48.78 V 38.88 V 9.90 V apart
Current at max power 13.12 A 9.79 A 3.33 A apart
Cell count 156 66 90 cells apart
Bifacial Yes No Yes vs No
Dimensions 2465x1133x35 mm 1795x990x38 mm 2465x1133x35 mm vs 1795x990x38 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
640 XL
21,577 kWh
380 BK
12,291 kWh
Lifetime gap
9,286 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario 640 XL 380 BK
Standard test conditions 25 °C 100.0% of rated power 640 W 380 W
Cool, bright day 40 °C 94.3% of rated power 612 W 359 W
Typical summer roof 55 °C 88.7% of rated power 584 W 337 W
Hot roof 70 °C 83.0% of rated power 556 W 316 W
03

Full specification

Parameter 640 XL 380 BK Difference
Power and efficiency
Rated power 640 Wp 380 Wp +260 W for 640 XL
Module efficiency 22.92 % 21.40 % +1.52 pp for 640 XL
Power density 229.2 Wp/m² 213.8 Wp/m² +15.3 Wp/m² for 640 XL
Open-circuit voltage 57.76 V 45.13 V 12.63 V apart
Voltage at max power 48.78 V 38.88 V 9.90 V apart
Short-circuit current 13.76 A 10.50 A 3.26 A apart
Current at max power 13.12 A 9.79 A 3.33 A apart
Temperature
Temperature coefficient -0.290 %/°C -0.377 %/°C +0.087 %/°C for 640 XL
Mechanical
Dimensions 2465x1133x35 mm 1795x990x38 mm 2465x1133x35 mm vs 1795x990x38 mm
Module area 2.793 m² 1.777 m² 1.016 m² apart
Weight 29.5 kg 19.0 kg -10.5 kg for 380 BK
Weight per kWp 46.1 kg/kWp 50.0 kg/kWp -3.9 kg/kWp for 640 XL
Warranty and degradation
Product warranty 25 yrs 25 yrs Same
Performance warranty 30 yrs 30 yrs Same
Annual degradation 0.30 %/yr 0.50 %/yr -0.20 %/yr for 640 XL
Technology
Cell technology N-type PERC N-type vs PERC
Cell type Monocrystalline Monocrystalline Same
Cell count 156 66 90 cells apart
Bifacial Yes No Yes vs No
04

Against the whole database

14,129 panels
Efficiency
#2,403 vs #8,388
640 XL leads by 5,985 places
Power density
#2,433 vs #8,409
640 XL leads by 5,976 places
Heat behaviour
#2,220 vs #13,470
640 XL leads by 11,250 places
Weight
#1,004 vs #3,329
640 XL leads by 2,325 places
Warranty
#21 vs #21
Tied - the same position in the database
Overall
#661 vs #9,853
640 XL leads by 9,192 places
05

More useful comparisons

Open the full database
Same series, other bin
Silfab
Silfab SIL-640 XL vs Silfab SIL-630 XL
3 differences, the largest is module efficiency
Same series, other bin
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Silfab SIL-640 XL vs Silfab SIL-620 XL
3 differences, the largest is module efficiency
Same series, other bin
Silfab
Silfab SIL-380 BK vs Silfab SIL-430 BG+
9 differences, the largest is rated power
Same series, other bin
Silfab
Silfab SIL-380 BK vs Silfab SIL-420-BG
10 differences, the largest is rated power
Same series, other bin
Silfab
Silfab SIL-380 BK vs Silfab SIL-410-BG
7 differences, the largest is annual degradation
Same series, other bin
Silfab
Silfab SIL-380 BK vs Silfab SIL-370 BK
3 differences, the largest is module efficiency
06

Written summary

07

Questions about this pairing

Which panel is better: Silfab SIL-640 XL or Silfab SIL-380 BK?
According to our database: Silfab SIL-640 XL has higher module efficiency (22.92% vs 21.40%); Silfab SIL-640 XL tolerates heat better (temp coeff -0.290%/°C vs -0.377%/°C). See the full spec comparison and 30-year energy simulation above for a complete picture.
What is the efficiency of Silfab SIL-640 XL and Silfab SIL-380 BK?
Silfab SIL-640 XL has a module efficiency of 22.92%, while Silfab SIL-380 BK is 21.40%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does Silfab SIL-640 XL use vs Silfab SIL-380 BK?
Silfab SIL-640 XL uses N-type cells; Silfab SIL-380 BK 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 Silfab SIL-640 XL and Silfab SIL-380 BK?
Silfab SIL-640 XL has a 30 years power warranty; Silfab SIL-380 BK has a 30 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.
Are Silfab SIL-640 XL and Silfab SIL-380 BK bifacial panels?
Silfab SIL-640 XL is bifacial (captures light from both faces); Silfab SIL-380 BK is monofacial. Bifacial panels work best on ground mounts or raised structures with a light-coloured surface underneath.

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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.