Skip to main content
520 QM vs 580-XM+-BIFACIAL 8 of 19 identical Swap Change panels

Silfab SIL-520 QM vs Silfab SIL-580-XM+-BIFACIAL

Silfab SIL-520 QM
Silfab
SIL-520 QM
520 Wp 21.90 % N-type
Open panel page Datasheet PDF
VS
Silfab
SIL-580-XM+-BIFACIAL
580 Wp 22.40 % N-type Bifacial
Open panel page Datasheet PDF
The verdict

580-XM+-BIFACIAL leads on the differences that matter

The largest is rated power: 60 W more power. 8 of 19 comparable parameters are identical.

See all 11 differences
How alike are they
8 of 19 comparable
parameters are identical
identical differs
01

What actually differs

11 of 19 parameters
Parameter 520 QM 580-XM+-BIFACIAL Difference
Rated power 520 Wp 580 Wp 60 W more power
Module efficiency 21.90 % 22.40 % 0.50 pp more efficient
Open-circuit voltage 47.52 V 52.27 V 4.75 V apart
Module area 2.377 m² 2.581 m² 0.204 m² apart
Power density 218.8 Wp/m² 224.7 Wp/m² 6.0 Wp/m² higher
Weight 26.2 kg 28.5 kg 2.3 kg lighter
Cell count 132 144 12 cells apart
Annual degradation 0.35 %/yr 0.30 %/yr 0.05 %/yr slower
Voltage at max power 40.48 V 44.27 V 3.79 V apart
Bifacial No Yes No vs Yes
Dimensions 2098x1133x35 mm 2278x1133x35 mm 2098x1133x35 mm vs 2278x1133x35 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
Same temp coeff. for both panels (-0.290 %/°C), so a warmer roof scales both curves by the same factor: the totals fall together and neither panel gains on the other.
520 QM
17,396 kWh
580-XM+-BIFACIAL
19,554 kWh
Lifetime gap
2,158 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario 520 QM 580-XM+-BIFACIAL
Standard test conditions 25 °C 100.0% of rated power 520 W 580 W
Cool, bright day 40 °C 95.7% of rated power 497 W 555 W
Typical summer roof 55 °C 91.3% of rated power 475 W 530 W
Hot roof 70 °C 87.0% of rated power 452 W 504 W
03

Full specification

Parameter 520 QM 580-XM+-BIFACIAL Difference
Power and efficiency
Rated power 520 Wp 580 Wp +60 W for 580-XM+-BIFACIAL
Module efficiency 21.90 % 22.40 % +0.50 pp for 580-XM+-BIFACIAL
Power density 218.8 Wp/m² 224.7 Wp/m² +6.0 Wp/m² for 580-XM+-BIFACIAL
Open-circuit voltage 47.52 V 52.27 V 4.75 V apart
Voltage at max power 40.48 V 44.27 V 3.79 V apart
Short-circuit current 13.65 A 13.85 A Effectively the same
Current at max power 12.85 A 13.10 A Effectively the same
Temperature
Temperature coefficient -0.290 %/°C -0.290 %/°C Same
Mechanical
Dimensions 2098x1133x35 mm 2278x1133x35 mm 2098x1133x35 mm vs 2278x1133x35 mm
Module area 2.377 m² 2.581 m² 0.204 m² apart
Weight 26.2 kg 28.5 kg -2.3 kg for 520 QM
Weight per kWp 50.4 kg/kWp 49.1 kg/kWp Effectively the same
Warranty and degradation
Product warranty 25 yrs 25 yrs Same
Performance warranty 30 yrs 30 yrs Same
Annual degradation 0.35 %/yr 0.30 %/yr -0.05 %/yr for 580-XM+-BIFACIAL
Technology
Cell technology N-type N-type Same
Cell type Monocrystalline Monocrystalline Same
Cell count 132 144 12 cells apart
Bifacial No Yes No vs Yes
04

Against the whole database

14,005 panels
Efficiency
#6,783 vs #4,774
580-XM+-BIFACIAL leads by 2,009 places
Power density
#6,837 vs #4,528
580-XM+-BIFACIAL leads by 2,309 places
Heat behaviour
#2,165 vs #2,165
Tied - the same position in the database
Weight
#3,761 vs #2,767
580-XM+-BIFACIAL leads by 994 places
Warranty
#21 vs #21
Tied - the same position in the database
Overall
#4,485 vs #2,018
580-XM+-BIFACIAL leads by 2,467 places
05

More useful comparisons

Open the full database
Same series, other bin
Silfab
Silfab SIL-520 QM vs Silfab SIL-590 XM+
11 differences, the largest is module efficiency
Same series, other bin
Silfab
Silfab SIL-520 QM vs Silfab SIL-570 XM+ BIFACIAL
9 differences, the largest is rated power
Same series, other bin
Silfab
Silfab SIL-520 QM vs Silfab SIL-570 XM+
10 differences, the largest is rated power
Same series, other bin
Silfab
Silfab SIL-520 QM vs Silfab SIL-530 XM
4 differences, the largest is module efficiency
Same series, other bin
Silfab
Silfab SIL-520 QM vs Silfab SIL-520 XM
3 differences, the largest is cell technology
Same manufacturer
Silfab
Silfab SIL-520 QM vs Silfab SIL-640 XL
12 differences, the largest is module efficiency
06

Written summary

07

Questions about this pairing

Which panel is better: Silfab SIL-520 QM or Silfab SIL-580-XM+-BIFACIAL?
According to our database: Silfab SIL-580-XM+-BIFACIAL has higher module efficiency (22.40% vs 21.90%). See the full spec comparison and 30-year energy simulation above for a complete picture.
What is the efficiency of Silfab SIL-520 QM and Silfab SIL-580-XM+-BIFACIAL?
Silfab SIL-520 QM has a module efficiency of 21.90%, while Silfab SIL-580-XM+-BIFACIAL is 22.40%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does Silfab SIL-520 QM use vs Silfab SIL-580-XM+-BIFACIAL?
Silfab SIL-520 QM uses N-type cells; Silfab SIL-580-XM+-BIFACIAL 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-520 QM and Silfab SIL-580-XM+-BIFACIAL?
Silfab SIL-520 QM has a 30 years power warranty; Silfab SIL-580-XM+-BIFACIAL 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-520 QM and Silfab SIL-580-XM+-BIFACIAL bifacial panels?
Silfab SIL-580-XM+-BIFACIAL is bifacial (captures light from both faces); Silfab SIL-520 QM is monofacial. Bifacial panels work best on ground mounts or raised structures with a light-coloured surface underneath.

Shop prices: See 2 Silfab 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.