Rob_E

Trying to figure out my next headlight. I have an IQ Cyo on my commuter. I was thinking of going with the IQ-X on my mountain bike with the rationale that it would see more off-road action where the 100 lumens might come in handy vs. the 80 of the Cyo. But I don't really know how much of a difference those numbers make, and I still do a fair amount of riding on the road and on MUPs where I don't want to blind on-coming traffic. Sometimes cars will flash their brights at me when I'm using my Cyo or my old, sort-of-functional Luxos U that's currently on my mountain bike. I could probably just angle it down a little, but then I have less visibility when I'm away from the streetlights.

Anyhow, I feel like that Luxos U is living on borrowed time, and I'm wondering if the IQ-X is overkill. That was my original plan, but I'm leaning towards the Cyo after riding with it a while. Plus, the idea that I'm going to need to light up the forests as night seems like a rare enough occurrence to not really worry about, plus, if it did happen, odds are good that I'd be going slowly enough that it might be better to have a lower powered light that comes on at lower speeds, if that's how these things work. Certainly with my lights currently it seems like they are either fully on or fully off.

Tourist in MSN

I have used neither, but I have a Luxos U and a IQ-XS. Both are pretty similar to each other, I always use the Luxos U on lower power.

Their website has sample beam patterns.

Cyo
https://www.bumm.de/en/products/dyna...75qrtsndi.html

And this is the beam pattern for it.
https://www.bumm.de/files/Produkte/40%20Lux.jpg

X
https://www.bumm.de/en/products/dyna...silber%20.html

And beam pattern for that:
https://www.bumm.de/files/Produkte/1...ux,%20IQ-X.jpg

For a mountain bike, if you have much up and down, I wonder if a B&M light with that sharp cutoff is best, you might be better off with a less sophisticated light that has less of a cutoff for mountain biking trails. But I have no clue what kind of mountain biking you do. If I was doing trail riding with a dyno powered light with a shart cuttoff I would probably want a helmet mounted battery powered light with a pretty strong beam in addition to the dyno powered light.

unterhausen

I have an IQ-X and a Cyo. I use the Cyo on my gravel bike. I do more serious night riding on my road bike so the IQ-X is on that. It's notably better, but I don't ride the two bikes back to back.

I suppose the big thing with mountain bikes is slow speed light. I am not particularly impressed with either light at slow speeds. My luxos U was horrible on long climbs though, I'm glad the IQ-X is better than that.

I wish they had the IQ-X in the IQ-XS case.

znomit

I have both and prefer the wider beam on the X, better for spotting critters on the side of the road.

But its me 

I used to run an IQ-X before upgrading to an Edelux. The output was impressive, but the mounting bracket was a weak point, being plastic. The bracket did not handle below freezing temperatures all that well, and ended up breaking at some point. Not sure why Busch and Mueller did not include one of their simple, but functional metal brackets. I used a Supernova metal bracket, which is worlds better (and still in use with Edelux). With a mountain bike, I assume the bracket will not last long. Also the IQ-X quickly lost auto function of daytime running light, with just manual regular beam or off as options.

unterhausen

I have broken the bracket on an IQ-X trying to adjust it on the road. You can easily replace it. It's a clever way of being able to make it hang upside down or right side up, but that's pretty useless in my book. That's why I wish they would put the IQ-X in the IQ-SX case

The Edelux II is nominally not as bright as the IQ-X, but I'm not so sure they didn't upgrade the emitter, it seems like it's the same brightness to me.

Andrey

I also have both lights and I use a small additional battery light on both bikes .

I prefer the CYO premium over the IQ-X for off road, because it does not flicker as much at lower speed and although it is not as bright it spills more light to the sides than with the IQ-X light.

With CYO I also run a cheep battery light to get more light in front and to the sides. IQ_X is brighter but borders between light and darkness are much sharper, so you not see to corners too well. For that reason I also prefer to run a small battery light with wider beam, even on the road.

2_i 

As differently powered lights were mentioned, let me venture into the power source area for IQ-Cyo and IQ-X. Even though B&M said that IQ-Cyo is for dynamo systems only, I have powered them fine with DC, specifically with a couple of lithium cells in series. USB output worked fine too, in my memory. I have moved these lamps freely between bikes, on some powered by dynamo and on other by DC and even rectified AC. However, IQ-X seems to have finicky electronics that does not tolerate variations in the delivered power. Can anyone thrown in any practical experiences around that?

znomit

The cyo manual states DC is OK. Not so for the IQ-X.

Tourist in MSN

I recall reading somewhere that someone tried DC on a Luxos U and blew the circuits, but I do not recall where I saw that or what voltage.

The B&M 2020 catalog lists two ways to power dyno powered lights with something other than a dynohub, one for testing and one for setting up a store display on page 52. The photo of the tester has a 6V notation on the device. I can't read the printing on the device to power the display.

Recently I had a Li Ion battery that somehow got overcharged, meter said 4.2 volts and I wanted to drain down the power somewhat. Based in part on seeing that 6V tester, I assumed that a dyno powered taillight would not be harmed, so I used that to slowly drain some power from my Li Ion battery, that worked just fine and it gave me a chance to see what the light pattern from the light was like. My curiosity got to me and I tried two other taillights to see what the light pattern was like on them too.

I would not start applying DC to any lights based on my comments here, but you might try to find if the instructions for either the tester or display power supply are available on line.

The following is text I pasted from that page in the catalog:

➊ Lightchecker Light, type 1516LC1: Simple
checking of headlights and rear lights. With
quick connection terminals.
➋ Light adapter, type 447LIA: Show the full
output of headlights in display windows or
during sales pitches – without using a dynamo. Connect the light adapter to the mains
and the headlight to the quick connection
terminals.
Please note: With the lightchecker, the full
light output may not be demonstrated.

2_i 

From the instructions for IQ-Cyo Senso currently on my bike and powered there by DC:



Admittedly, instructions for some of the first IQ_Cyos stated that you could use the lamp with a battery, but at your own risk.

All LED lamps are obviously DC internally. The first thing they do with AC is that they rectify it and smooth it out. If you start with a DC and you run it through the process, you get the same outcome as when starting with AC. It is absolutely irrelevant in that sense, for the lamp interior, whether you feed the lamp with AC or DC. However, there may be a difference if the AC pulses are used for something before power delivery to the main light unit. I saw on an occasion a difference in operation depending on the polarity of DC fed to a lamp. It looked like only one polarity of AC was used to charge the standlight capacitor, maybe to limit the power taken away from the main light unit during that charging. IQ-X seems to use the pulse frequency, though, to make some decisions for the lamp, though. This seems to explain why you should use it with hub but not bottle dynamos. The latter have pulse frequency about 3x higher than hub. I normally put lamp switches in on position and decide on the lamps being on or off with outside circuitry. Having to stop to put the lamp on or off makes in itself no sense to me and a flimsy switch on a rubber band, at times, does not make sense either. I.e., if IQ-X could be put to always on, I would not care what it does with the pulses, but it seems that there is no such option for that lamp, hence my poking around with the questions pertaining to practical experiences.

As to the DC powering of front vs rear lights, the brake versions of the rear are likely to test pulse frequency, so one could expect some issues there.

As maybe one more comment, when you look at the voltage from the dynamo side on an oscilloscope, when the dynamo is loaded with a front LED lamp, the voltage has nothing to do with a nice textbook sinusoidal profile, that the dynamo yields with no load, but becomes trapezoidal and nearly square like. After rectification, it is DC with notches. Weird form of voltage is already there when you operate the dynamo system by the book.

Tourist in MSN

Luxos U and also the AXA Luxx 70 Plus have different LEDs lit up at higher speed than at low, that might also be based on frequency, but I am only guessing on that.

I am not an electronics engineer, never had a circuits class, but I can say that I found with some LED headlights that the hub voltage appeared to have a maximum level regardous of speed, almost as if they had some zener diodes to drain off excess current, that could cause the odd shape you see on the oscilloscope. I do not know why they would do that, but it is my understanding that most taillights lack overvoltage protection, thus I am guessing that the headlights cap the line voltage to protect the taillight.

On the other hand, lights off, my voltage out of the hub climbs quite high down a hill.

I agree with your statement that "It is absolutely irrelevant in that sense, for the lamp interior, whether you feed the lamp with AC or DC. ", but I do recall someone commenting that they blew out the circuits to a Luxos U using DC.

2_i 

I am primarily self-taught, but then my learning was getting validated with a use of that knowledge in my day job and the electronics even became the main focus during some periods. The dynamo behaves as a current source within some range of its operation so when the load represents low resistance the voltage drops and the sinusoidal function gets clipped. In the same fashion, voltage goes high when there is no load. As to the protection in the taillights, I think it must have improved over time. In the past, I would routinely open the lights and put the Zeners there before even attempting to use the light. Most recently I have not heard people lamenting that their rear light blew up when the front went off.

This blowing of the Luxos U with DC presumably was due to an overvolting and the lack of the current limiting feature of the source. Quite meager lithium batteries can deliver many amps if you try to shorten them. Incidentally, my DC for the lights has a thermistor on the output to protect against shortening. The thermistor costs some cents.

Tourist in MSN

I suspect that is because the LED headlamps do not burn out like incandescent did AND everybody wires the taillight to the headlight circuit now. And the headlight provides the over-voltage protection.

For example, I pasted this from Peter White website:
The Secula Plus taillight must only be connected to the headlight. When the headlight is switched on or off, the taillight will be switched on or off as well. Then the taillight will only get the power it needs, and won't be damaged by the full power of the dynamo.

steelbikeguy

in regards to the question of AC or DC, I agree that most lights just rectify the AC, so DC is probably not a problem.
The bigger issue could be that some lights rely on the fact that dynamos won't generate more than 0.5A, so they don't include any circuitry to limit the current. I fixed a Supernova headlight that worked this way. It had been connected to an e-bike's battery, and quite a bit of the circuitry was damaged as a result.

Some lights use bidirectional zener diodes to clamp the dynamo voltage to a safe level. This also relies on the dynamo only providing 0.5A. If the light is connected to a battery that has a high enough voltage to cause the zener to conduct, it is very possible to exceed the diode's ratings. A zener subjected to excess current may fail as a short circuit. If the battery is connected to a shorted zener, there could be damage to circuit board, the wiring, or in some cases, might cause the silicon in the zener to turn to gas and blow the diode apart.

Other lights use high voltage protection diodes known as TVS (transient voltage suppressor) diodes. I have been given a dead B&M Eyc light, which I have been slowly reverse engineering. I was very surprised to learn that it uses a TVS diode rated at 100V! It's extremely rare to see 100V from a dynamo. The only time I've seen it has been riding my bike downhill at 50mph with just a protection zener as a load for the dynamo. This was part of some design work I was doing for a light. Any light designed to handle 100V from a dynamo would probably be happy to be powered from any battery that you've got around the house.

Steve in Peoria

znomit

The 100V might be from if the dynamo isn't connected securely... If your plug comes loose at speed and then reconnects thats what you can expect. Boom.

steelbikeguy

true.... that's not going to be good either.
I haven't tried to dig up a manual for the Eyc, but I think it lets the user turn it off with a push button. This means that the light will keep at least some circuitry operating while the LED is unpowered. The lack of a load on the dynamo could produce this sort of high voltage at high speeds, I think I was drawing at least a few milliamps through the 100V zener during my downhill test runs.
I am curious about what mosfets are used in the switcher. My guess is that the little micro is directly acting as the controller for the buck converter. There are a couple of 6 pin devices that could conceivably be 100V mosfets....



the other side of the board doesn't have anything that seems likely to be a suitable high voltage mosfet... although I suppose a sot-23 device might do the job??




I really need to find time to work on this.. <sigh>

Steve in Peoria

JaccoW

@Rob_E sounds like you might enjoy the modified Laempie.de version of the Cyo or the IQ-X. Both have upgraded LEDs with a switchable high-beam or floodlight function.

I have used the normal Cyo Premium and the normal IQ-X and I have only had other road users complain with the IQ-X even though I had them set up exactly the same way.
If you have cars complaining (and the light should cut off at bumper level) then it is aiming too high. Even set up like this there is enough spill that reflective surfaces such as signs still light up.

Below is a video of his modified IQ-X. Note the change in the beam around the 0:14 mark.

Tourist in MSN

I try to aim my dyno powered headlamps that have a cut-off beam so that when I ride in an urban area at night, I get reflection from the parked car taillights as I pass them, but not much light above the taillights.

That said, the dyno powered headlights are not as bright as the H4 Halogen headlight that I used to use driving my motorcycle at night, that was something like 1100 to 1500 lumens, low beam was at 55 watts. And a lot of cars had two of the same headlamps.

I used to commute through a university campus and when I was driving home after work the only bicycle headlights that were a problem for me as a car driver were the people with the super bright battery lights on strobe light mode.

Rob_E

That's my biggest concern. Combined with the bracket issues mentioned on the IQ-X, it sounds like there's no reason to not to stick with the Cyo.

Also, I feel a little better about the twisting mode selector on the Cyo vs. what appears to be a single, multi-functional button on the IQ-X. I have no idea if one is really better than the other, but I do like that I can change the mode between on/off/sensor mode when the bike is stopped and still know which mode I'm in. The IQ-X reminds me of my Luxos U where I can't tell unless the light has power.

If I'm actually doing extended night riding away from the city lights, which I haven't been able to do lately, I also like an additional headlamp, so I always have light in the direction I'm looking, not just where the bike is pointed.

Andrey

I actually do not bother to turn both lights off, they are always set to auto "on" once the bikes start moving. IQ-X switch could only be turned on/off when the light is powered by the hub, CYO has just a mechanical switch that could be used when the light is off.
I prefer CYO to ride off road, because of more light spill to the sides. Either light may not have enough light to ride off road technical descends, I also use an additional battery light for that.

Rob_E

Yeah, I'm the same, but I have had situations with my Luxos U where someone saw that I had left my light on and "helpfully" turned it off. Since the remote button on my Luxos doesn't work, and the light is mounted out of reach when I'm riding, I'd have to lift the front up, spin the wheel, and cycle through button presses until I found "on." Pain in the ***. Especially since it always could be a situation where a wire came loose. So I'm a little wary of similar designs. Really like that if my Cyo doesn't immediately turn on when I start, I can glance at the dial and know whether the light is turned on or not.

Germany_chris

IIRC the Edelux II uses the bulb and reflector out the IQ-X

unterhausen

The light output looks very similar to me, but the information I have seen gives a lower output rating to the Edelux II and Peter J. White's website used to say it was the same as a cyo premium. His website is a bit of a jumble, so I didn't find it.

Who am I to believe, the internet or my lying eyes?

Manufacturers often upgrade lights as better emitters become available. I have wondered if they did this with the Edelux II. It was released over 6 years ago.

znomit

The Edelux II is the Cyo premium optics. Supposedly they drive a bit harder/cool a bit better than the B&M. The IQ-X is brighter and wider.