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The only times you can see a typical diesel spill (ok, crude oil would be more obvious!) are in daytime when it's sitting on top of a wet road and gives a blue, sometimes rainbow, effect. The local farmer used to leave a mile-long trail of it on my commute.

Lumens are a bit meaningless. Lux according to StVZO are at least comparable. 60 lux is enough for fast riding on unlit lanes but not for 50mph downhills. 40 lux is ok for town commuting.

rogerzilla wrote: ↑2 Sep 2024, 7:39am The only times you can see a typical diesel spill (ok, crude oil would be more obvious!) are in daytime when it's sitting on top of a wet road and gives a blue, sometimes rainbow, effect. The local farmer used to leave a mile-long trail of it on my commute.

Lumens are a bit meaningless. Lux according to StVZO are at least comparable. 60 lux is enough for fast riding on unlit lanes but not for 50mph downhills. 40 lux is ok for town commuting.

Lux (a measure of the luminous intensity at a surface (lumens per square metre)
The intensity should be stated for a certain area at a distance from the light source.
A very narrow beam could produce a high lux level at a distance of say 2m but may not be much use.
OTOH a wide beam with a lower lux level may be much more effective.
I have a dynamo powered Edelux 2 which gives a very good beam. I don't ride at night much now but the Edelux is set too low as I realised
during a winter audax when the beam was fine at my normal slow speed but not giving sufficient illumination at a further distance going downhill.
The problem with cycle lighting is that you can only illuminate a small amount of what is visible in normal daylight which means you have to be much more careful at night.

my current wheelset is gone. Too damaged, needs to be replaced.

R.I.P.

For the new front wheel, I'm thinking of an H-Son rim with a dynamo hub.
Umm, as far as I can see from datasheet, the max a front dynamo hub can power is 3 Watts.
I can add a super booster capacitor(1) for extra emergency current.
However, a capacitor is not a battery, it can accumulate energy,
but then it returns it with a decreasing exponential function

Vout(t)=V1- delta_V*exp(-tao*t)
tao = Req * C
delta_V=V1-V0=(Vout(t1)-Vout(t0))
range(Vout)={ V0..V1}
range(t)={t0 .. t1}={0 ... ~ 5*tao}

C is the capacity property of the supercapacitor, say C in a supercapacitor@5V is 2 Farad

Anyway, its voltage output must be regulated by a Switching DC/DC,
and it can only help the headlight to make more light for a very limited time.

The point is: the supercapacitor recharges much faster than a battery
you use the dynamo to keep it always charged
and you use it only in emergencies
i.e. maybe putting a button on the handlebar (or, on the ErgoPower?)
to make more light in very bad spots on the road

ANTONISH wrote: ↑2 Sep 2024, 9:49am dynamo powered Edelux 2 which gives a very good beam

What exactly are you using as a dynamo?
I need to figure out how much current the led needs for a given lux/lumen parameter

current = f (lux)
f = ???
lux = ???


(1) with cell protectors and balancers

I've put hub dynamos on all of our tourers and am very pleased with the illumination from the several different B+M headlamps.

Why is that calculation of energy conversion needed? There's lots of experiences and recommendations in the archives, and the basic check is that the dynamo will produce enough power for the lamp.

Jonathan

PS: And following Nearholmer's comments for on-road and off-road needs I'd add another headlamp for off-road, rather than that affecting the choice of dynamo-powered headlamp.

DiTBho wrote: ↑31 Aug 2024, 7:13pm Which points to the question: how many lumens do you need?

As others have noted, the measures of lumens, lux etc can be nearly meaningless if the lens shape is poor. Early days of decent lighting, there were various lights claiming to be the most powerful but with lens shapes so bad that the power wasn't going where it was needed.

That said, 400 lumens for travelling at 45kph on a dark road in poor condition is nowhere near enough. Possibly exacerbated by 23c tyres at 100psi.

My road light will do up to 2400 lumens and that'll do most MTB / gravel as well. Even my little urban / commuting light will do 1000 on full power and that's bare minimum for things like canal towpath.

And none of them will show up oil or diesel spills on already wet roads.

You can suck a lot more than 3W from a hub dynamo, as they try to push a constant current. A twin SON E6 setup was quite popular among audaxers before LEDs. The catch is that (obviously) drag is higher when drawing more power, and the minimum speed is higher for lighting all lamps fully.

When I first looked into dynamo lighting there was a light that did what you described, It had a capacitor to store some of the dynamo power and then automatically increased output when you got above a certain speed. It was svtzo compliant so all that would be focused on the road. Unfortunately I can't remember the brand/make and I haven't seen it around for a while so probably discontinued.

The other thing to remember is our eyes are incredibly adaptive, so switching from 60 lux to 70 lux will look a lot brighter, but within a few miles you really won't notice any difference. So unless you know roughly where the oil spill is then above a certain point numbers don't matter that much

DiTBho wrote: ↑2 Sep 2024, 10:11am For the new front wheel, I'm thinking of an H-Son rim with a dynamo hub.
Umm, as far as I can see from datasheet, the max a front dynamo hub can power is 3 Watts.
I can add a super booster capacitor(1) for extra emergency current.
However, a capacitor is not a battery, it can accumulate energy,
but then it returns it with a decreasing exponential function

The best lighting system IMO is to have two lights. I find a decent dynamo light to be more than adequate for the majority of my riding, I then supplement that with a very bright battery light. I chose a Trek one with a remote switch so it's easy to operate without taking a hand off the bars. It gets used for pitch black country lanes, fast downhills, off road, in the rain, to remind drivers to dip, sometimes on flash at dusk or dawn, sometimes just because it's nice to have that much light. In fact pretty much the way you'd use a high and low beam on a motor vehicle and obviously, like a high beam, it isn't used where it would blind others. I've done several overnight rides, using the battery light whenever required, and finished with some capacity left. To get through the night I do conserve it, but I don't worry about run time, I can get by fine with just the dynamo light if I need to. If you think that might be an issue, you can chose a light with pass through, that is can be used while charging, and take a power bank.
We are a bit spoilt for choice, we can find lights to match however we wish to ride, unlike a few years ago when we had to match our riding to the lights available. It's easy to forget that the second still remains an option.

And following Nearholmer's comments for on-road and off-road needs I'd add another headlamp for off-road, rather than that affecting the choice of dynamo-powered headlamp.

Yes, I don’t keep the “blaster” on a bike all the time, just strap it on for rides that might need it, as an addition to the “be seen, and do a bit of basic seeing” lights that I have on all my bikes, all the time (they happen to be rechargeable, rather than dynamo, but the same principle applies).

The “blaster” set on one of its lower settings is also good for camping. I get an empty 1L plastic milk bottle, which I put over the end of it to create a diffuser, thereby making a lantern. In fact last w/e during family camping by car, I made a big lantern using it with a 10L Jerry can as a diffuser!

rogerzilla wrote: ↑2 Sep 2024, 11:24am You can suck a lot more than 3W from a hub dynamo, as they try to push a constant current. A twin SON E6 setup was quite popular among audaxers before LEDs. The catch is that (obviously) drag is higher when drawing more power, and the minimum speed is higher for lighting all lamps fully.

I still use twin halogen lights in the manner described above.
They give sufficient light from low speed with a hub dynamo

Riding unlit roads in pitch blackness you need a good light to see ahead. My advice - buy a well regarded make, a minimum of 800 lumens and with a battery life able to cope with the runs you do in the dark plus an hours contingency. Replaceable batteries are another plus. I have a Moon Meteor Fog (also called Moon Meteor Dual) 1600 lumen max output though I usually only need around 800 of those. It has twin colour led emitters - one white, one yellow/white. The yellow/white has noticeably less back scatter in fog and drizzle(i.e. Scottish year round weather!)
IME Vittoria tyres tend to have a hard and less grippy compund than others such as Schwalbe or Continental. 23mm tyres are less grippy than anything larger but maybe you were limited with fork clearance.
The earlier comments about riding fast while tired are apt but we've likely all done it and mostly were lucky enough to get away with it. In the dark, relying on my lights to see the road I'm going to be cycling well below 30km/hr. Oil and diesel on the road are horribly slippery and likely to have taken you out no matter if you hit it. With the energy of impact being proportional to speed^2 the damage is disproportionately greater for small increases in speed.
Hope you and your bike mend soon.

Bear in mind that most of the cheap megalumen lights will dazzle other road users. Only the German approved ones gave a proper cut-off like a car's dipped beam.

Some pedestrians on cyclepaths will complain about ANY bike light dazzling them, but that's just normal cyclist hatred.

I don't think there is any light that would pick up diesel on a wet road. Not even broad day-light.

ANTONISH wrote: ↑2 Sep 2024, 9:49am

rogerzilla wrote: ↑2 Sep 2024, 7:39am The only times you can see a typical diesel spill (ok, crude oil would be more obvious!) are in daytime when it's sitting on top of a wet road and gives a blue, sometimes rainbow, effect. The local farmer used to leave a mile-long trail of it on my commute.

Lumens are a bit meaningless. Lux according to StVZO are at least comparable. 60 lux is enough for fast riding on unlit lanes but not for 50mph downhills. 40 lux is ok for town commuting.

Lux (a measure of the luminous intensity at a surface (lumens per square metre)
The intensity should be stated for a certain area at a distance from the light source.
A very narrow beam could produce a high lux level at a distance of say 2m but may not be much use.
OTOH a wide beam with a lower lux level may be much more effective.

I'm sure the area and distance will be specified in the StVZO.