An OT question, but I think the people who know the answer may be here. Pre-LED the hubs developed X potential to drive those lights. Now people want to charge their USB stuff, so I doubt there will be a desire to drop the potential much. But if you just ran the generator system for lights, you could get the same amount of output we had with incandescent lights out of LEDs, for maybe 1/10th the electrical load. So the question is, what are the new LED generator light systems like. Do they just blow the old incandescent systems out of the water, or are they the same general light level, and the same general resistance on the pedals?

I used to have a fancy German system on a recumbent bike, and it ran off the tire. That would be a perfect technology to run at normal light levels, but with LEDs and with very much reduced drag, because those systems do let you know they are there, and they can badly wear your tire. But if they had near zero drag, they would be a real option for someone who just wanted to run lights.