The IQ-XL (e-bike version) draws a bit more than 9W in low beam and around 12,5-13W in high beam. The low beam is darker when the high beam is switched on, but for normal bicycle speeds there is plenty of light. I have sped down hilly roads at 80 km/h with my velomobile with this light in high beam mode and the light was still more than sufficient. The nice feature of the IQ-XL is the warmer light color, i'd guess around 5000-5500K, not the 6500-7000K in usual StVZO lights.
Actually, the Lupine SL-F is in high beam also darker (lux!) than in low beam, as in low beam 16W are pushed trough 6 LEDs and in high beam 16W are pushed trough 12 LEDs. So of course the intensity of the light is reduced, as the lumens are spread over a wider area

12.5-13W is about the max you can draw from a (conventional) dyno hub. B&M is pretty conservative with their "minimum 16W rated power" requirements, as the take into account the rear light as well. In theory the light could be powered with up to 40 W (i got this information from a B&M guy) in high beam mode.

The IQ-XL has 12 LED dies. 3 of them in a row are used for the low beam, 2x3 are added for high beam and 3x1 LEDs are used for daylight running light. In the (sorry german) mtb-news.de/forum there are a pictures of the lamp head. LEDs for day lighting: Link to picture; and here are the 9 main leds for low (red circle) and high beam: link to picture

The dyno version is still not yet released, i fear it won't be released this (northern hemisphere) winter. I heard issues with the electrics..

polyphrast: I intend to mount a head light on the Tubus Grand Expedition Rack. I am concerned about the length of the wire on the high beam switch being long enough. Can that switches wire be easily lengthened?. The Rack is designed with a headlight mount.

It is a 3x0.14mm^2 unshielded cable (you have to convert this to awg yourself), and the 3 wires have different colours. You'll loose officially the waranty though (this was told me by the BUMM support). I lengthened the cable myself, no issues since two years

I don't know where this 12W figure is coming from. The saturation wattage of a SON 28-QR is approx 9.5W. I know the core of the SON 28-12 is a little larger but wouldn't expect a jump to 12W.

This isn't correct. :)

If the LED's are equal and linear (let's assume they are) then shunting half the power from the first LED into the second LED produces half the lumens in each emitter (so the same lumens overall) and the same lux. Lux is collated light in an area, the equation is 1 lux = 1 lumen per square meter.

Lux is a more ideal measurement as it factors in a) the efficiency of the reflector and transmission index of the glass or b) collimator

Yes indeed I'm glad I'm not the only one that picked up on it and pointed it out to Schmidt some months back. Our test rig shows about 9.5W at circa 35kph (I don't have the exact figure to hand) but only with reactance tuning - a straight resistive load won't reach this but 7.7W sounds right as generally reactance tuning (where phase=zero) nets a 25% gain, so bang on the money. This is the saturation point of the SON28-QR. The figure also correlates with what the German enthusiast websites get.

Maybe they're saying what the Ladelux can support for the future. In that case we'd have to start marketing Igaro C1 as 40W when Ladelux comes to market. :thumb:

Well, they showed their ladelux in combination with their new dynohub, designed for more power draw.
From the guy at BUMM who developed the electronics of the IQ-XL AC. He succeded to allow the power draw required to get those 250 lux (which is 12,5-13W for the DC version if the IQ-XL). But it might be possible, that this will be reached at speeds above 30 kph.
A forumslader v5 can draw 10,5W from a SON 28 at 30 kph. See fig 10 in this german article.

This is generally speaking correct, but not with respect to lux values stated for StVZO lights. As you know, the advertised values is measured at the brightest spot of the light, just below the cut-off. If you power the low beam leds only half and put the other half into the high beam LEDs, you do not get the same Lux value at that defined spot, as the additionally powered LEDs for high beam light up a different part of the road.
For instance the IQ-XL and the Lupine SL-F get notably darker in the area of the low beam when the high beam is added, although both lights emit more lumens at high beam. For other lights, i.e. the Lupine SL-X or the Supernova M99, this is different, but those lights draw significantly more power in high beam than in low beam.

Schmidt said it was with the SON 28 (I don't know which variant). I don't believe the test kit in that German article is that accurate. You can see two multimeters for voltage and current which infers wattage isn't RMS based, it is being multiplied, which isn't representative of absolute wattage. Devices like Forumslader will not realistically get to phase=0 and so the two aren't the same. Supporting this is what they measure at USB (so DC where phase isn't applicable) where they net 8.5W so a 19% loss. This is higher than would be expected from rectification and DC-DC regulation with a 10.5W input.

I didn't know that about StVZO and wonder if it's an assumption to say manufacturers are doing it when they don't state it? When I last looked at StVZO regs (which admittedly was a while back and now ISO ones seem to be taking over) the lux only had to meet minimums and have certain percents in certain areas. If I use our own product (Igaro C1), the max is 230 lux in entirety, which is 8W at the LED so a bit higher at the hub. If the M99 is measuring 200 lux just at the brightest spot that would insinuate it's doing something like 300 lux overall, which is not only above what dynamo power can provide but the M99 isn't drawing the hubs maximum power. This leads me to believe Supernova isn't doing what you say. I may be missing something but that's my logic!

Much of it is of course academic and only beneficial for marketing purposes. Most riders won't be sitting at these higher speeds or necessarily wanting to go full power downhill, indeed they'd be benefited more from consistent light across the wide range of speed that riders do. This is something Schmidt are about to learn, because when USB enters the mix it becomes a compromise and one compromise doesn't necessarily suit all riders. When they say "power your light and charge at the same time" that's not going to be what most riders experience, but it might be their expectation, and from this comes disappointment and returns.

"Much of it is of course academic and only beneficial for marketing purposes. ..." Indeed, but please satisfy my curiosity and explain "saturation wattage". With a load that adjusts to the speed, I would, perhaps naively, not expect any limit to power output. Assuming impractically high speeds are actually possible, of course.

The author of this article, Andreas Öhler, is working at Schmidt developing the Ladelux. I highly suspect that he knows well what he does.
There is only a requirements, that in a quite small area (4° left and right and 1.5° degree down of the spot with the highest lux value), half of the maximum lux value has to be achived. There is no massive amount of lumens required for this. Here is a link (sorry, german) for the respective TA23 which regulates the dipped beam. Supernova does not state at which speed the 200 lux are achieved. The M99 pedelec versions (same reflector, same LEDs) delivers in low beam 450 lumens / 150 lux at 5.2W. Supernova shows a lumen/speed graph on their product page (Link, scroll down). You need more than 50 kp/h to achieve max power output, so the 1000 lumens are quite feasible. At 30 kph the claim ~650 lumens for the low beam and 750 lumens for the high beam, so the wattage at that speed is already higher than that of the pedelec version

How are you accessing your first link? Chrome doesn't let you connect due to protocol mismatch and offers no option to ignore.

An inductor (which is what a generator is) works by storing charge and releasing it. When it stores too much charge the inductance drops and it begins to progress to a short. The point just before this begins is known as the saturation point.

As a more practical example consider a wind turbine. Why do they never go insanely fast when the wind is high? ;)

Of course, but Andreas is a mechanical engineer. He doesn't do the testing it's another person called Schultz.

Let's take the 1000 lumens claim and see where it leads. The Igaro C1 has a 650 lumen emitter, which at full output consumes 8W at the LED (2A, 4V, tested). The actual input wattage at the hub will of course be higher but lets assume a) all LED's are equal and b) system efficiency is 100%.

650 / 8 = 0.0123076923077
0.0123076923077 * 1000 = 12.31W, at the LED

Let's assume 90% transfer efficiency.

12.31 / 0.9 = 13.68W, at the hub

Both values are above what even Schmidt claim they can extract, a figure which for all my testing (ref -igaro.com/testrig) says is not possible.

Most dynamo light manufacturers are indicating the lumens that the LED die specification states. It doesn't necessarily reach it, which is why I berate the usage.

they adjust the blade pitch.
Those are all over the place here. Really neat!
I've watched them feather the blades in order to stop the rotation. Must have not been enough demand on the grid?

https://live.staticflickr.com/4084/5...bf94c5_c_d.jpg

Steve in Peoria

I didn't know that, the old? ones had brake pads in them. Variable pitch is nicer but probably more expensive!

You come along with facts and understanding and think you're going to pop the technobabble balloon?

Fat chance! This "discussion" train has a lead and a head of steam that'll outrun any reality check!

they may still have brake pads, but the variable pitch blades are handy too. Obviously, they permit optimizing the blade angle in order to get the most power out of the air flow.

In this shot, I think it can be seen that the blades are feathered.
https://live.staticflickr.com/65535/...21f5db_b_d.jpg

We've got a couple of local coal fueled power plants, but one was recently decommissioned. There have been more and more wind turbine installations over the last 20 years, which I find encouraging. Besides... if there are enough of them, they'll start to slow down the headwinds that I have to fight when riding the bike. :)

Steve in Peoria

It has been a while since I saw a map of where it's economic to put a wind turbine, but there aren't many places where they would make money in Pennsylvania other than at the top of mountains. So I'm afraid that they aren't going to be slowing down our headwinds any time soon.

One of the challenges of moving away from fossil fuels towards something sustainable is figuring out what is locally available, or how to bring in energy from elsewhere. One big challenge of generating remote electricity is finding a place to build new transmission lines. Getting permission to install towers and such is a big issue.

Surprisingly, or maybe not, there are some folks who object to seeing wind turbines over the corn fields. It might be the usual resistance to change. It's usually farmers who object to the change, but it's also farmers who benefit financially from renting land for the wind turbine sites.

The wind turbines that I show in my earlier posts have been in place for around 20 years. Haven't heard any complaints from the folks in the area. Personally, I think they look at least as nice as a soybean field. :)

https://live.staticflickr.com/4393/3...4826a2_b_d.jpg

https://live.staticflickr.com/65535/...72a225_b_d.jpg

Steve in Peoria

Andreas Öhler does the testing of all tests involving hub generators. Olaf Schultz does the testing of dynos running on the tire or rim (i.e. Velogical and PedalCell)

With the known exception of the IQ-XL nearly all StVZO Lights use automotive emitters with an Efficiency of >100 lm/W. Often they use multiple emitters (the m99 dy has 3 or 5 LEDs for low beam and another 5 or more for high beam)
Optical losses due to reflectors and front glasses are small, lens based systems have higher losses.

Schmidt refers the 12W to practical speeds (maybe 30kph), Supernova refers the max output to speeds at a fast descent (above 50kph)

Schmidt also doesnt power the emitter in their Ladelux with more than 4-5 Watts for low beam, all excess power goes into the Buffer battery or the USB device.

StVZO (dynamo) light manufacturer do not state any lumens at all, the state lux values. The ones that state lumens (Supernova, Lupine) use Ulbricht spheres for measurements of their Lights
Lupine specifies their reflector based low beam lights with luminous efficiencies of 100-110 lm/W after optical losses.

That could explain why the figures are based on two multimeters and thus wrong. The concept of true/absolute power is difficult for none electrical-engineers (I do for the record have great respect for Andreas/Schmidt and in no way wish to demean their efforts). Anyhow they can print what they like and I'll do my usual thing of questioning the validity!

There isn't a huge difference between good LED's anyhow at the current level that dynamo can manage. Ours is 151lm/W (datasheet).

I didn't see that review until a few posts later and noted the reported lumens are lower than the claimed figure, however all of these spheres are calibrated on a known device and the scope for error between different spheres (i.e size!) is huge. I like the idea of standardizing the approach, perhaps we manufacturers could work together to create the specification for a sphere/sensor which anyone can replicate.

A USB output sink can't just decide to send variable "excess" current/power. It agrees a current level and has to meet it otherwise many USB devices in particular phones establish it as a fault. So it has to be the other way round, USB is always priority, however doing so could mean the light output doesn't meet StVZO minimums and on it goes. When it comes to the R&D side of this I may have the t-shirt.

Regarding lights, Andreas & Schultz are already planning their next benchmarking session, I know because Andreas emailed about how to test the Igaro C1 in it. The test comprises of a dynamo rig running at 20kph/700c and measuring the light output. I mentioned that is it not a valid test. Here's the points I raised -

1. 20kph is chosen why? Probably because Ladalux is using two 330uF capacitors back to back for an optimal reactance point of 20kph/700c. However a fixed capacitance only gives about a 5-10kph window either side before it becomes detrimental. This means lights like M99 are then at an advantage. It doesn't bother me for the Igaro C1 because it uses switched and variable capacitance and so optimises for a wider range of speed, but I want to see fairness across the board.

2. Not all lights have a feedback loop for maximum output they may shunt power into batteries or super-capacitors. The Igaro C1 doesn't at all, it uses charge bands and so will eventually switch up and down, and the super-capacitors are huge so this doesn't happen with a frequency that lends itself to being measured by the approach they are using. Ultimately no rider sits at exactly 20kph anyway, it's not real-world realistic.

3. They aren't capturing light over time but at a single point in time. Many lights use PWM for regulation (I believe M99 does) and this will skew the reads if they don't capture and average over time.

I recommended they use a saw type speed ramp and capture light after an hour (to let any batteries charge up), digitally, and average it over a further 15 minutes or so. It means they need to invest in their test equipment!

Good chatting with someone knowledgeable in the domain. I enjoy it. :thumb:

I think some of it is politics. My sister wanted to add solar panels to her roof on her house. She is in a housing development that has a home owner association. A member of the association board kept throwing up road blocks in her attempt to add the panels. Wanting to be sustainable is becoming a political statement to some extremists that have opposing views.

A few days ago, @igarocom wrote: "An inductor (which is what a generator is) works by storing charge and releasing it. When it stores too much charge the inductance drops and it begins to progress to a short. The point just before this begins is known as the saturation point."

I guess you are talking about magnetic saturation here, and now I am more curious. Do you have measurement(s) of the the current where saturation begins in specific dynamos? If these newer lamps and chargers can induce it, the saturation level might be a distinguishing characteristic, particularly as they all have the same nominal power output.

I would expect saturation to only put a downward bend in in the graph of available power versus speed, not be a hard limit. But I may have misinterpreted "saturation wattage".

Not to hand sorry, and I'm not a dynamo hub design expert by any means but I'll try my best. Claw type dynamos are fixed current (it does differ a little at low speed but then stabilizes). The SON28-QR is about 560mA. So if you take a figure posted earlier let's say 9.5W,with the ideal load and impedance phase=0, voltage is 17V.

You are right on the downward bend, take a look at the graph on the German website a few posts ^^. The forumslader induces the saturation point earlier due to reactance tuning and then the power begins to drop.

which is ok, because speeds higher than 30 kph are not reasonable for someone doing long distance touring.

i have read and saved quite a few tests from (german)bicycle magazines, where lights from all kind of manufacturers where either tested in the lupine ullbricht sphere or in the supernova ullbricht sphere (in one test for consistency in both spheres). The values for the given lights do vary very little between the two spheres. (for instance, the IQ-XL is measured at 500 and 840 lumens and the supernova M99 Mini Pro 25 (the ebike version of the M99 Dy) delivers 450 and 1550 lumens, which is for the latter pretty close to the manufacturers spec...

i am quite shure that this is not conform with StVZO regulations ( i don't do this kind of testing, but i am involved in automotive component testing and certification, so i have some experience interpreting norms). So at least during night the Ladelux has to switch off the USB Power out if the speed drops too much and the demand from the USB devices cannot be satisfied from the internal battery.

because either a StVZO hub or a StVZO light (or both) has to meet the requirements at 15 kph. And 20 kph is a reasonable speed for a average person on a bike (without motor)

PWM Frequencies are usally so high that a multimeter or a lab power supply will only measure and show the average. Even a for standard indicator relay, you do not see the correct zero/max reading with a conventional multimeter or lab power supply, and that pwm frequence is roughly (1/0.7)s with duty cycle iof 50%. I have measured my fair share of motorcycle indicators, e-bike and battery powered lights and only with an oscilloscope you can detect influences from PWM regulation.

Maybe you could supply it to them. Keep in mind, Öhler and Schmitz do this in their free time with their private money for a magazine which is free of charge. i would keep costs reasonable low as well and the current setups do their job good enough. I am very glad for their wide spread and continuuos testing.