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670M66-HUV vs 665M66-HU/BF-DG 14 of 19 identical Swap Change panels

EGing PV EG-670M66-HUV vs EGing PV EG-665M66-HU/BF-DG

EGing PV EG-670M66-HUV
EGing PV
EG-670M66-HUV
670 Wp 21.56 % PERC
Open panel page Datasheet PDF
VS
EGing PV
EG-665M66-HU/BF-DG
665 Wp 21.40 % PERC Bifacial
Open panel page Datasheet PDF
The verdict

5 differences, and they point both ways

The largest is performance warranty: 5 yrs longer. 14 of 19 comparable parameters are identical.

See all 5 differences
How alike are they
14 of 19 comparable
parameters are identical
identical differs
01

What actually differs

5 of 19 parameters
Parameter 670M66-HUV 665M66-HU/BF-DG Difference
Performance warranty 25 yrs 30 yrs 5 yrs longer
Weight 32.9 kg 38.3 kg 5.4 kg lighter
Weight per kWp 49.1 kg/kWp 57.6 kg/kWp 8.5 kg/kWp lighter
Annual degradation 0.55 %/yr 0.45 %/yr 0.10 %/yr slower
Bifacial No Yes No vs Yes
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.
670M66-HUV
21,714 kWh
665M66-HU/BF-DG
21,899 kWh
Lifetime gap
185 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario 670M66-HUV 665M66-HU/BF-DG
Standard test conditions 25 °C 100.0% of rated power 670 W 665 W
Cool, bright day 40 °C 94.9% of rated power 636 W 631 W
Typical summer roof 55 °C 89.8% of rated power 602 W 597 W
Hot roof 70 °C 84.7% of rated power 567 W 563 W
03

Full specification

Parameter 670M66-HUV 665M66-HU/BF-DG Difference
Power and efficiency
Rated power 670 Wp 665 Wp Effectively the same
Module efficiency 21.56 % 21.40 % Effectively the same
Power density 215.7 Wp/m² 214.1 Wp/m² Effectively the same
Open-circuit voltage 45.97 V 46.02 V Effectively the same
Voltage at max power 38.16 V 38.22 V Effectively the same
Short-circuit current 18.61 A 18.45 A Effectively the same
Current at max power 17.56 A 17.40 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 32.9 kg 38.3 kg -5.4 kg for 670M66-HUV
Weight per kWp 49.1 kg/kWp 57.6 kg/kWp -8.5 kg/kWp for 670M66-HUV
Warranty and degradation
Product warranty 12 yrs 12 yrs Same
Performance warranty 25 yrs 30 yrs +5 yrs for 665M66-HU/BF-DG
Annual degradation 0.55 %/yr 0.45 %/yr -0.10 %/yr for 665M66-HU/BF-DG
Technology
Cell technology PERC PERC Same
Cell type Monocrystalline Monocrystalline Same
Cell count 132 132 Same
Bifacial No Yes No vs Yes
04

Against the whole database

14,005 panels
Efficiency
#7,774 vs #8,323
670M66-HUV leads by 549 places
Power density
#7,644 vs #8,250
670M66-HUV leads by 606 places
Heat behaviour
#8,778 vs #8,778
Tied - the same position in the database
Weight
#2,745 vs #11,303
670M66-HUV leads by 8,558 places
Warranty
#9,798 vs #21
665M66-HU/BF-DG leads by 9,777 places
Overall
#3,378 vs #2,833
665M66-HU/BF-DG leads by 545 places
05

More useful comparisons

Open the full database
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06

Written summary

07

Questions about this pairing

Which panel is better: EGing PV EG-670M66-HUV or EGing PV EG-665M66-HU/BF-DG?
According to our database: EGing PV EG-670M66-HUV has higher module efficiency (21.56% vs 21.40%). See the full spec comparison and 30-year energy simulation above for a complete picture.
What is the efficiency of EGing PV EG-670M66-HUV and EGing PV EG-665M66-HU/BF-DG?
EGing PV EG-670M66-HUV has a module efficiency of 21.56%, while EGing PV EG-665M66-HU/BF-DG is 21.40%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does EGing PV EG-670M66-HUV use vs EGing PV EG-665M66-HU/BF-DG?
EGing PV EG-670M66-HUV uses PERC cells; EGing PV EG-665M66-HU/BF-DG 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 EGing PV EG-670M66-HUV and EGing PV EG-665M66-HU/BF-DG?
EGing PV EG-670M66-HUV has a 25 years power warranty; EGing PV EG-665M66-HU/BF-DG 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 EGing PV EG-670M66-HUV and EGing PV EG-665M66-HU/BF-DG bifacial panels?
EGing PV EG-665M66-HU/BF-DG is bifacial (captures light from both faces); EGing PV EG-670M66-HUV 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.