On Friday, April 2, 2021 at 11:40:08 AM UTC-5, Mark J. wrote:
On 4/2/2021 3:09 AM, wrote:
As for dynamo lights. For randonneuring, they are almost required because you are riding so long in darkness at night. Batteries would not work. But for riding around town, I have been more of a battery person than dynamo person. I have both types of lights. Battery lights are much more powerful and provide a couple hours of light. More than enough for evening recreational rides or commuting. One two hour evening rides a couple times a week or commuting morning or evening are the predominant uses of lights. Batteries work very well for these kinds of rides. Its very uncommon for someone to ride all night long and require a dynamo.

While I like my dyno hub and Luxos headlamp for randonneuring, I did two
of my super randonneur series with batteries, and liked 'em just fine.
And the first one was with lead-acid (heavy!) batteries. It was the
superior beam pattern on the Luxos (bought for my commuter) that
persuaded me to convert the rando bike to dyno.

Frankly, prior to well-engineered LED headlights, dynos just didn't
provide enough light for my tastes. Riding all night is much more
stressful when you have to struggle to see road hazards.

Mark J.

Yes I can see that. Depending on how you ride randonneur rides. 200k, no light needed, 13.5 hour time limit. 300k, 20 hour limit, only need light 1/2 hour in the morning and 2-3 hours maybe in the evening. 400k, 27 hour limit, 1 hour morning, 2 hours evening, stop for sleep, 2 hours next morning.. On low power batteries can give 4-5 hours of light. 600k, 40 hour limit, 1 hour morning, 2 hours evening, stop for sleep, 1 hour morning, ride all day and get in before need lights in evening. You may be cutting it a bit close if you do not finish quick enough on the second day of riding. No margin for error. But doable. And for the 1000k at 75 hours and the 1200k at 90 hours, they will also work with batteries but will require a new battery/recharge for the second half of the rides. Again doable with the correct planning and no unexpected emergencies arise.

But dynamo on brevets eliminate most of the worry from the unexpected emergencies and you don't have to do any planning at all for night riding. I'd definitely recommend a dynamo for randonneur brevet riding. On my PBP I had a support car so I could have maybe planned to meet my support at approved stops at the right times before dark and gotten fresh batteries. That would have taken a whole lot of planning and luck to work. Not something I want to count on during a timed 1200k. And of course with the much better LED lights for dynamos now, you can get good lighting out of a dynamo. If you are willing to pay the upfront cost and your usage, riding patterns warrant a dynamo.

I used the old filament lights on my dynamo in 2007 and the prior year too when I did an extra 1200k to get ready for PBP. Busch Mueller 6V lights. Two of them for my Shimano dynamo. One each side of the front hub. They provided the minimum amount of light. Minimum. You always wanted more light. I have since upgraded to some B&M LED lights. Two. Much, much better. When I rode brevets, I sometimes rode through the night on 400, 600, 600, 1000, 1200 rides. No sleep stops. So I needed longer run times than batteries could provide.