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370 BK vs 620 XL 3 of 19 identical Swap Change panels

Silfab SIL-370 BK vs Silfab SIL-620 XL

Silfab
SIL-370 BK
370 Wp 20.80 % PERC
Open panel page Datasheet PDF
VS
Silfab
SIL-620 XL
620 Wp 22.20 % N-type Bifacial
Open panel page Datasheet PDF
The verdict

620 XL leads on the differences that matter

The largest is module efficiency: 1.40 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 370 BK 620 XL Difference
Module efficiency 20.80 % 22.20 % 1.40 pp more efficient
Temperature coefficient -0.377 %/°C -0.290 %/°C 0.087 %/°C better in heat
Rated power 370 Wp 620 Wp 250 W more power
Power density 208.2 Wp/m² 222.0 Wp/m² 13.8 Wp/m² higher
Annual degradation 0.50 %/yr 0.30 %/yr 0.20 %/yr slower
Weight 19.0 kg 29.5 kg 10.5 kg lighter
Open-circuit voltage 44.76 V 57.21 V 12.45 V apart
Short-circuit current 10.33 A 13.55 A 3.22 A apart
Module area 1.777 m² 2.793 m² 1.016 m² apart
Weight per kWp 51.4 kg/kWp 47.6 kg/kWp 3.8 kg/kWp lighter
Cell technology PERC N-type PERC vs N-type
Voltage at max power 38.34 V 48.16 V 9.82 V apart
Current at max power 9.69 A 12.87 A 3.18 A apart
Cell count 66 156 90 cells apart
Bifacial No Yes No vs Yes
Dimensions 1795x990x38 mm 2465x1133x35 mm 1795x990x38 mm vs 2465x1133x35 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
370 BK
11,968 kWh
620 XL
20,903 kWh
Lifetime gap
8,935 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario 370 BK 620 XL
Standard test conditions 25 °C 100.0% of rated power 370 W 620 W
Cool, bright day 40 °C 94.3% of rated power 349 W 593 W
Typical summer roof 55 °C 88.7% of rated power 328 W 566 W
Hot roof 70 °C 83.0% of rated power 307 W 539 W
03

Full specification

Parameter 370 BK 620 XL Difference
Power and efficiency
Rated power 370 Wp 620 Wp +250 W for 620 XL
Module efficiency 20.80 % 22.20 % +1.40 pp for 620 XL
Power density 208.2 Wp/m² 222.0 Wp/m² +13.8 Wp/m² for 620 XL
Open-circuit voltage 44.76 V 57.21 V 12.45 V apart
Voltage at max power 38.34 V 48.16 V 9.82 V apart
Short-circuit current 10.33 A 13.55 A 3.22 A apart
Current at max power 9.69 A 12.87 A 3.18 A apart
Temperature
Temperature coefficient -0.377 %/°C -0.290 %/°C +0.087 %/°C for 620 XL
Mechanical
Dimensions 1795x990x38 mm 2465x1133x35 mm 1795x990x38 mm vs 2465x1133x35 mm
Module area 1.777 m² 2.793 m² 1.016 m² apart
Weight 19.0 kg 29.5 kg -10.5 kg for 370 BK
Weight per kWp 51.4 kg/kWp 47.6 kg/kWp -3.8 kg/kWp for 620 XL
Warranty and degradation
Product warranty 25 yrs 25 yrs Same
Performance warranty 30 yrs 30 yrs Same
Annual degradation 0.50 %/yr 0.30 %/yr -0.20 %/yr for 620 XL
Technology
Cell technology PERC N-type PERC vs N-type
Cell type Monocrystalline Monocrystalline Same
Cell count 66 156 90 cells apart
Bifacial No Yes No vs Yes
04

Against the whole database

14,129 panels
Efficiency
#10,533 vs #5,881
620 XL leads by 4,652 places
Power density
#10,528 vs #5,913
620 XL leads by 4,615 places
Heat behaviour
#13,470 vs #2,220
620 XL leads by 11,250 places
Weight
#4,742 vs #1,762
620 XL leads by 2,980 places
Warranty
#21 vs #21
Tied - the same position in the database
Overall
#10,529 vs #1,420
620 XL leads by 9,109 places
05

More useful comparisons

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

Written summary

07

Questions about this pairing

Which panel is better: Silfab SIL-370 BK or Silfab SIL-620 XL?
According to our database: Silfab SIL-620 XL has higher module efficiency (22.20% vs 20.80%); Silfab SIL-620 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-370 BK and Silfab SIL-620 XL?
Silfab SIL-370 BK has a module efficiency of 20.80%, while Silfab SIL-620 XL is 22.20%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does Silfab SIL-370 BK use vs Silfab SIL-620 XL?
Silfab SIL-370 BK uses PERC cells; Silfab SIL-620 XL uses N-type. 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-370 BK and Silfab SIL-620 XL?
Silfab SIL-370 BK has a 30 years power warranty; Silfab SIL-620 XL 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-370 BK and Silfab SIL-620 XL bifacial panels?
Silfab SIL-620 XL is bifacial (captures light from both faces); Silfab SIL-370 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.