They guys at BUMM are well aware of the differences in AC and DC current. I got confirmed that the AC/Dynamo version of the IQ-XL delivers (above certain speed thresholds) the exact same light/lumen output as the DC version (in the end, the current through the LED is relevant, not what happens before the power electronics), which is also stated on the B&M webpage... As written here before: At 25 km/h the low beam delivers full power (9,5-10W input for the DC version), at 35 km/h the high beam delivers full power (12,2-12,5W input for the DC version). I do not know whether the AC and DC electronics have the same efficiency or differ in efficiency, so i can't give you AC input wattage numbers, but you probably can backcalculate from the DC input values. I also do not know, which tire was used for those tests (i guess a 700C touring tire), so depending on tire diameter, those speed thresholds may vary a bit.