Skip to main content
RSF XL-G11S.3 / BFG 590 vs ML-G12S.3 / BFG 670 5 of 17 identical Swap Change panels

Q-Cells Q.PEAK DUO RSF XL-G11S.3 / BFG 590 vs Q-Cells Q.PEAK DUO ML-G12S.3 / BFG 670

Q-Cells Q.PEAK DUO RSF XL-G11S.3 / BFG 590
Q.PEAK DUO RSF XL-G11S.3 / BFG 590
590 Wp 21.10 % PERC Bifacial
Open panel page Datasheet PDF
VS
Q.PEAK DUO ML-G12S.3 / BFG 670
670 Wp 21.60 % Bifacial
Open panel page Datasheet PDF
The verdict

ML-G12S.3 / BFG 670 leads on the differences that matter

The largest is rated power: 80 W more power. 5 of 17 comparable parameters are identical, with 2 more left out because at least one datasheet does not publish them.

See all 12 differences
How alike are they
5 of 17 comparable
parameters are identical
identical differs not published
01

What actually differs

12 of 17 parameters
Parameter RSF XL-G11S.3 / BFG 590 ML-G12S.3 / BFG 670 Difference
Rated power 590 Wp 670 Wp 80 W more power
Module efficiency 21.10 % 21.60 % 0.50 pp more efficient
Open-circuit voltage 53.60 V 45.72 V 7.88 V apart
Short-circuit current 13.74 A 18.42 A 4.68 A apart
Module area 2.792 m² 3.106 m² 0.314 m² apart
Weight per kWp 61.7 kg/kWp 57.0 kg/kWp 4.7 kg/kWp lighter
Power density 211.3 Wp/m² 215.7 Wp/m² 4.4 Wp/m² higher
Weight 36.4 kg 38.2 kg 1.8 kg lighter
Voltage at max power 44.96 V 38.27 V 6.69 V apart
Current at max power 13.12 A 17.51 A 4.39 A apart
Cell count 156 132 24 cells apart
Dimensions 2462x1134x35 mm 2384x1303x35 mm 2462x1134x35 mm vs 2384x1303x35 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 (-0.340 %/°C), so a warmer roof scales both curves by the same factor: the totals fall together and neither panel gains on the other.
RSF XL-G11S.3 / BFG 590
19,429 kWh
ML-G12S.3 / BFG 670
22,064 kWh
Lifetime gap
2,635 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario RSF XL-G11S.3 / BFG 590 ML-G12S.3 / BFG 670
Standard test conditions 25 °C 100.0% of rated power 590 W 670 W
Cool, bright day 40 °C 94.9% of rated power 560 W 636 W
Typical summer roof 55 °C 89.8% of rated power 530 W 602 W
Hot roof 70 °C 84.7% of rated power 500 W 567 W
03

Full specification

Parameter RSF XL-G11S.3 / BFG 590 ML-G12S.3 / BFG 670 Difference
Power and efficiency
Rated power 590 Wp 670 Wp +80 W for ML-G12S.3 / BFG 670
Module efficiency 21.10 % 21.60 % +0.50 pp for ML-G12S.3 / BFG 670
Power density 211.3 Wp/m² 215.7 Wp/m² +4.4 Wp/m² for ML-G12S.3 / BFG 670
Open-circuit voltage 53.60 V 45.72 V 7.88 V apart
Voltage at max power 44.96 V 38.27 V 6.69 V apart
Short-circuit current 13.74 A 18.42 A 4.68 A apart
Current at max power 13.12 A 17.51 A 4.39 A apart
Temperature
Temperature coefficient -0.340 %/°C -0.340 %/°C Same
Mechanical
Dimensions 2462x1134x35 mm 2384x1303x35 mm 2462x1134x35 mm vs 2384x1303x35 mm
Module area 2.792 m² 3.106 m² 0.314 m² apart
Weight 36.4 kg 38.2 kg -1.8 kg for RSF XL-G11S.3 / BFG 590
Weight per kWp 61.7 kg/kWp 57.0 kg/kWp -4.7 kg/kWp for ML-G12S.3 / BFG 670
Warranty and degradation
Product warranty - 12 yrs Not published by Q-Cells
Performance warranty 30 yrs 30 yrs Same
Annual degradation 0.45 %/yr 0.45 %/yr Same
Technology
Cell technology PERC - Not published by Q-Cells
Cell type Monocrystalline Monocrystalline Same
Cell count 156 132 24 cells apart
Bifacial Yes Yes Same
04

Against the whole database

14,005 panels
Efficiency
#9,297 vs #7,652
ML-G12S.3 / BFG 670 leads by 1,645 places
Power density
#9,241 vs #7,644
ML-G12S.3 / BFG 670 leads by 1,597 places
Heat behaviour
#8,778 vs #8,778
Tied - the same position in the database
Weight
#12,677 vs #11,008
ML-G12S.3 / BFG 670 leads by 1,669 places
Warranty
#21 vs #21
Tied - the same position in the database
Overall
#8,523 vs #2,462
ML-G12S.3 / BFG 670 leads by 6,061 places
05

More useful comparisons

Open the full database
Same series, other bin
Q-Cells Q.PEAK DUO RSF XL-G11S.3 / BFG 590 vs Q-Cells Q.PEAK DUO RSF XL-G11S.3 / BFG 600
3 differences, the largest is module efficiency
Same series, other bin
Q-Cells Q.PEAK DUO RSF XL-G11S.3 / BFG 590 vs Q-Cells Q.PEAK DUO RSF XL-G11S.3 / BFG 595
One difference: module efficiency
Same series, other bin
Q-Cells Q.PEAK DUO RSF XL-G11S.3 / BFG 590 vs Q-Cells Q.PEAK DUO RSF XL-G11S.3 / BFG 585
The same specification on paper
Same series, other bin
Q-Cells Q.PEAK DUO ML-G12S.3 / BFG 670 vs Q-Cells Q.PEAK DUO ML-G12S.3 / BFG 675
The same specification on paper
Same series, other bin
Q-Cells Q.PEAK DUO ML-G12S.3 / BFG 670 vs Q-Cells Q.PEAK DUO ML-G12S.3 / BFG 665
One difference: module efficiency
Same series, other bin
Q-Cells Q.PEAK DUO ML-G12S.3 / BFG 670 vs Q-Cells Q.PEAK DUO ML-G12S.3 / BFG 660
3 differences, the largest is module efficiency
06

Written summary

07

Questions about this pairing

Which panel is better: Q-Cells Q.PEAK DUO RSF XL-G11S.3 / BFG 590 or Q-Cells Q.PEAK DUO ML-G12S.3 / BFG 670?
According to our database: Q-Cells Q.PEAK DUO ML-G12S.3 / BFG 670 has higher module efficiency (21.60% vs 21.10%). See the full spec comparison and 30-year energy simulation above for a complete picture.
What is the efficiency of Q-Cells Q.PEAK DUO RSF XL-G11S.3 / BFG 590 and Q-Cells Q.PEAK DUO ML-G12S.3 / BFG 670?
Q-Cells Q.PEAK DUO RSF XL-G11S.3 / BFG 590 has a module efficiency of 21.10%, while Q-Cells Q.PEAK DUO ML-G12S.3 / BFG 670 is 21.60%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does Q-Cells Q.PEAK DUO RSF XL-G11S.3 / BFG 590 use vs Q-Cells Q.PEAK DUO ML-G12S.3 / BFG 670?
Q-Cells Q.PEAK DUO RSF XL-G11S.3 / BFG 590 uses PERC cells; Q-Cells Q.PEAK DUO ML-G12S.3 / BFG 670 uses Monocrystalline. 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 Q-Cells Q.PEAK DUO RSF XL-G11S.3 / BFG 590 and Q-Cells Q.PEAK DUO ML-G12S.3 / BFG 670?
Q-Cells Q.PEAK DUO RSF XL-G11S.3 / BFG 590 has a 30 years power warranty; Q-Cells Q.PEAK DUO ML-G12S.3 / BFG 670 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 Q-Cells Q.PEAK DUO RSF XL-G11S.3 / BFG 590 and Q-Cells Q.PEAK DUO ML-G12S.3 / BFG 670 bifacial panels?
Both Q-Cells Q.PEAK DUO RSF XL-G11S.3 / BFG 590 and Q-Cells Q.PEAK DUO ML-G12S.3 / BFG 670 are bifacial - they capture reflected light from the ground, which can add 5-15% more annual energy on ground-mount or elevated rooftop installations with a light surface beneath.

Shop prices: See 25 Q-Cells 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.