Originally Posted by
tarwheel
Whatever works for you is fine, but one could easily make similar arguments in favor of battery lights. I don't want a bike with generator lights because they add weight, resistance and costs. My commute route is very hilly, and the last thing I want is something making it more difficult.
I'm a big advocate of dyno lights, but I also contend that battery lights have their place where they are the better option.
As for the weight issue: A Shimano 3N80 hub is ~475g, and a typical dyno lamp head is under 100g. The total weight of the system is approximately the same as that of a good battery lamp system with a modest runtime (3 - 4 hours).
Resistance: Jan Heine gives a 1.5% penalty to battery lighting vs. dyno lighting in the Cyclos Montagnards rules. IOW, dyno lights (on average) are only sapping 1.5% of your total performance. In an event like a 1200k grand randonnee, this can be a big deal; over 90 hours it can be a net loss of 81 minutes which may make or break getting to a late stage control in time. On a commute that averages 60 minutes with battery lights, switching to a dyno will bump that up to almost 61 minutes. It's like catching an extra red light.
From personal experience, you don't notice the additional resistance between lights on and lights off with a good dyno (3N70 or better).
Cost: A 3N72 can be had for under $100. You can buy a built up generator wheel with one for around $175, and an IQ Cyo lamp is around $120. So total investment is around $300 on the low end. Pricier than many mid-level battery driven systems, but not outrageous.
Where dyno lights really tip the scales is for endurance lighting: If you ride all night. Solo touring. Randonneuring. Having to carry enough batteries to get yourself 9 (or in some areas 12 or more) hours of lighting is when you'll really start racking up the weight. Whether you need it for 12 minutes or 12 hours, a generator setup always weighs the same amount.
Where battery systems have the advantage is 2-fold: Intensity is the first one. You won't find a generator lamp that can out-power the massive lumen output of a high-intensity battery system. If you need something for 24 hour racing where you have a pit crew that can swap batteries while you're eating dinner, a 1200L system will stomp a Supernova E3 Triple into the dirt. Transferrability is the other advantage: It's easy to swap a battery system between bikes and doesn't cost a dime extra to do it. It's not so easy with a dyno setup unless you can use the same wheel on every bike, and you still need to get one of the limited selection of swap-mountable lamps (most are hard mounted).