I just set up my first bottle-generator light system, using a cheap old dynamo (bought for a buck at a bike co-op) and a Busch & Muller Lumotec Oval headlight. I don't know what brand the dynamo is (it's got a "C" on the cap), but it's definitely low-end and old. Anyway, it feels like a BIG drag on the tire; I'm wondering whether A) they were all just like that, or B) I've got it set up wrong. If A), are the modern ones really any better? Advice on proper setup will be appreciated.

I keep hearing people say that a bottle generator shouldn't produce noticeable drag, but this one definitely does. Maybe I'm doing it wrong?

Personally, I've never used one that didn't feel like you forgot to take the winter trainer off.

Mine produce noticeable drag compared to no generator... biggest thing is to get it aligned properly. I run an AXA (I think) which is a decent bottle generator. Somewhere I have directions on how to set one up properly you have to have the generator axis at 90* to the wheel hub axis...if that makes sense.

I am preferring to run LED lights in that they put less draw on the generator and don't seem to bog it down as much as the older incandescent ones.

Aaron

Bigger draw means more drag?

Try to line up the bottle,so that a straight line through the bottle goes through the wheel spindle,it will be quieter when its correct.

I answered A on your question.

Old Union were DC, those had significant drag , 1 wire + hot lead,
ground thru the frame for the circuit return.

the newer like AXA-Basta, and B&M are Alternators, AC. those are lower drag.

The wire brush like B&M roller is an attempt to not have the drive drum hydroplane,
so easily.

hub Dynamos cure the wet weather problems inherent to bottle dynamos ..

I doubt you can run a modern LED headlight with an old DC generator.

halogen bulb maybe.. load must =3W, 2.4w head .6w rear, or 1_ 3w bulb, if not.

Regular screw base filament bulbs in 2.4w are getting hard to find .

By fiddling with the bracket (provided it's a clamp-on, not a frame boss), you can adjust not only the alignment, but the pressure that it places on the tire. I don't know if it makes a noticeable difference, but I set mine up for the minimum pressure at which the little wheelio would still spin.

Dynamo hubs definitely have more resistance when loaded. I don't know why this would not be the case with bottles.