Re: bike light optics

On 4/4/2024 7:16 PM, Roger Merriman wrote:

Frank Krygowski <frkrygow@sbcglobal.net> wrote:

On 4/4/2024 3:53 PM, Roger Merriman wrote:

>
urban roads small usb powered lights would be fine, as you don’t need light
to see by, I only flick mine to high beam in the woods/parks but I’m a
outlier, though london does have a fair bit of Green areas that you’d
probably want a light that you’d see by. Though in most it’s fairly mild
and doesn’t need anything that powerful.
>
Quite frankly anything StVZO is like my exposure light likely to be
overkill in terms of cost.

>
About the cost: For a long time I got by fine with various lights that
were very inexpensive. I experimented a bit with many headlights and
lighting arrangements, including rechargeables and home brews. I mostly
used dynamo halogen lamps by Union and Soubitez that focused the beam
quite well and were adequate for all my road riding, but not really
outstanding. The only setup that I considered a significant improvement
was two halogen lamps powered by my dynamo, and switchable (A or B or A+B).
>
But when I got my first B&M Cyo, I considered the problem solved and
stopped experimenting. It's a little pricey (~$100?) but I've spent far
more on other bike equipment. I can afford it, and it's such an
improvement. For me, it gives a luxurious amount of illumination.
>

The lamps as far as I can see are relatively speaking inexpensive, at least
compared roughly to batteries powered units, the expensive bit would seem
to be a Dynamo hub and wheel even if your building and installation
yourself, which is probably a technical hurdle beyond most.
 I’m really not a good fit for such lights, mainly that I want lights with
more power with the MTB/Gravel bike can get at least one dynamo lights with
a off road beam shaped but even so with a 3w limit it’s power output is
lacking for that purpose ie 800 lumens at 17mph+ my light kicks out at
least double that with potentially up to 3 times that, as it uses how fast
how much the bars are moving to gauge the light needed.

I'm curious: What light is that, and what did it cost?

 For the commute would a dynamo light be fine? Probably though even so I’d
probably miss even thats lights ability to light up the woods on high that
would mainly be beam shape than absolute power, as some dynamo lights
aren’t too far behind though most seem to be in the 200 ish lumen range.
 I’ve had lights in that range in the past, and that’s fine but what I have
is a better fit certainly for my commute, ie a mix of well lit roads and
unlit woods.
 Unless the cost of the dynamo system is built into the cost of the bike as
new, it’s a relatively hard sell, note the rise of E bike lights, ie they
plug into the main battery.

About the cost of the dynamo: Two of my bikes have hub dynamos. I built the wheels myself. But at least four other family bikes have B&M headlamps powered by bottle or roller dynamos. Most of those were given to me, so they don't have to be expensive. New ones of good quality are available for ~$40.
--
- Frank Krygowski