SOS: B&M LED Front Lights failing - (and now a Buchel) - Shimano Dyno Hub

[tt2cycletours]

Hi All,

Couldn't see a posting discussing failure of LED front lights by B&M; I have had two fail in last 2-3 years.

And now a Buchel LED front light (Secu City) has failed within 3 months (I am contacting manufacturer).

All the lights were sold with over voltage protection so is there something I need to change?

I am running a shimano 'DN72' hub (maybe 14,000 miles clocked now).

Are there LED front lights out there which just keep working?  I am a fast rider (for an enthusiast; could this be a factor)?

Symptoms have included lights always been on even if turned off (no not the stand light) but even so I thought the LEDs were rated to last literally thousands of hours??

Can anyone either shed light on cause of lights not lasting very long or suggest an alternative which are better made.  Do the expensive Schmidt lights last for years?

My commuter has a [Busch & Muller Lumotec Lyt B Senso Plus Headlight for Hub Dynamos] but this is permanently on (even if  not attached to the frame by the bracket) so I need to get something to replace it soon.

Sorry lots of questions here, any thoughts/advice would be appreciated or please direct me to an existing forum.

Thanks (I was initially impressed with the Buchel light and it has been great for 500+ miles in 3 months...)

[Danneaux]

Hello!

Looking at your post carefully, I see some things that may prove helpful going forward...

• You've had an unusually large number of failures for a single owner
• All the failures were front lights. What about the taillights?
• The lights have been from two different makers
• All have been used with the same Shimano dynohub, a DN72
• You're a fast rider
• All lights had overvoltage protection -- assuming it has not failed, that is supposed to protect the lights for fast riders.
• Lights have always been on even if turned off (not sure I understand this...perhaps the switch isn't working properly?)

A couple questions/thoughts...
• How do the lights fail...do they simply fail to light? Or, do they not turn off and then eventually no longer work?
• How are the lights wired? Do they use a dual lead directly from the dynohub, or does one path use the bike frame as a return to the dynohub source?
• Is there a short in the wiring, most likely at the dynohub plug (I've seen some cases where a single strand came free of the plug and shorted out against something metal).
• How are the headlights mounted? On their factory mounts, or on something custom?
• If you're not running a slave-powered taillight (one attached to and supplied by the headlight), what about the unused leads/lugs on the headlights? Could something be shorting across them, say when turning the handlebars?

First thing I'd do is mount the bike in a stand so the front wheel can spin freely and then attach a voltmeter to see how much power is being output by the hub. If all is well there, I'd backtrace from the dynohub, looking for faults. A cheap voltmeter would be a good investment compared to another headlight that could fail in turn.

I do remember when B&M first introduced the IQ Cyo, there were a number of failures traceable to the switch assembly. Depending on age and model, might yours be from an older, faulty batch?

Sorry to not offer anything definitive, but hopefully something in the above will prove helpful in tracing this frustrating and expensive problem.

Best,

Dan.

[Andre Jute]

Dan has already given you a pretty thorough analysis and further questions. The BUMM switches are not the best, but a fused switch that leaves the lamp on permanently is better viewed as a hint to use daylight running lamps than an imperative to replace the lamp. Something else is going on here.

A light permanently on is a symptom, not a cause; you're right, a LED with a 50Khours MTBF shouldn't fail unless overvolted.

Or unless it gets wet. Inspect the underside of your BUMM lamps. They're open. Water can get in and ruin them.  So the first important question is: Which of your bikes have mudguards?

***
The Schmidt Edelux lamps last longer by being better cooled and consequently permitting better sealing against water. There is also a perception that they are generally better made, even though they use the same optics as the BUMM IQ Cyo.

[Danneaux]

Or unless it gets wet. Inspect the underside of your BUMM lamps. They're open.Water can get in and ruin them.  So the first important question is: Do which of your bikes do you have mudguards?

In the absence of more information, I really think Andre might be onto something here. Here (Stateside) it is popular for owners of randonneur and porteur bikes to mount their lights *under* their front platform racks (if so fitted), or *alongside* the front tire, exposing the sometimes unshielded underside and backside of the headlights to a continuous spray of water when riding in the rain.

Looking at posts in various fora and a mention of same by Peter White, there appears to be a known correlation between this sort of spray exposure and LED lamps failing. While correlation shouldn't be taken as causation, there is enough of a link there to raise real suspicion, so it might be worth changing the mounting location or fitting a mudguard if one is absent, just as Andre suggested.

Best,

Dan.

[tt2cycletours]

Thanks to you both for such a quick responses.  Both bikes have mudguards (a commuter and a tourer) and I didn't have this problem with the old style halogen dynamo lights with a shimano switch ('nexus').

Did an initial test on commuter voltage output and it was about 11V at 10mph but I will check this again to be sure.  I wonder if both too high a voltage and water-damage are to blame.  Certainly the first BUMM light to fail had lost the little rubber bung at the bottom and I was never very careful when washing the bike (perceived them to be weather proof).

The BUMM which failed this summer (this is permanently on when rolling, regardles of switch position) had four weeks in Norway last summer.  It was also left outside in the rain sometimes on its side.

Thanks again, Tim

[tt2cycletours]

I have just bitten the bullet and bought another B&M (round ones, 25lux LED, about £30+) light for my commuter bike, from Rose Bikes.  The instructions are quite clear that these lights are NOT waterproof .  So I will treat the thing with kid gloves when I wash the bike.  It is the vents at the bottom which let water in.

I have now had three of these B&M lights fail (on different bikes) so I can't trust them for touring use.

Are there any lights out there cheaper than the Schmidt Edelux High Power LED Headlight but which are also waterproof so appropriate for say...  ...use on a bicycle for instance.

I haven't checked the voltage output on my touring bike yet but I  never realised these lights weren't waterproof and it seams the most likely explanation.

Thanks, Tim

[Danneaux]

I haven't checked the voltage output on my touring bike yet but I  never realised these lights weren't waterproof and it seams the most likely explanation.

Hi Tim!

I understand your concern (and the expense caused by all these failures -- wow!), and I can offer two more focused suggestions after reading your latest missive:

1) Is the bike ever stored or parked so it is laid sideways in the rain? It seems unlikely, but if the bike is laid on its side, it is possible water could enter the light housings. Most of the B&M lights have openings of some sort on the underside. I recall seeing a photo on the Dutch Weraldfietser (world cyclist) forum showing a small insect trapped *behind* the lens of an IQ Cyo. It had crawled up through the opening and had become trapped inside.

2) Far more likely is the other common denominator -- dynohub output. I'd sure be interested to see what your readings are for the Shimano  hub. It is just possible it is putting out way too much voltage for the lamps to endure.

Your experiences are unusual -- really! -- and this is heartening in the bigger picture. It points to some commonality across brands and models, so the problem source must be a constant. You've identified both, I think...now to isolate which one is causing the problem. My money's now on the dynohub output.

A distant last on the list of contributing factors might be the wiring. Have you renewed it with each new light, or re-used some of what is already in place? Also, have you tested the lights after they showed signs of failure on this bike? I would presume you'd find an open circuit.

'Sure hope this helps; all empathy and sympathy your way on this bedeviling and expensive problem.

Best,

Dan.

[tt2cycletours]

Thanks - I usually wash the bikes upside down, so ample opportunity to get water inside; I usually hose down to rinse.

The touring bike was frequently left on its side in the rain over-night so ample opportunity for water to get inside...  I had about two solid days of rain in Norway last July although manged to sleep in the sauna of a very quiet campsite one of the days; sadly not enough space or audacity to include the bicycle!

But I will check the hub dynamos as you suggest...

Thanks, Tim

[Danneaux]

I usually wash the bikes upside down, so ample opportunity to get water inside; I usually hose down to rinse.

...and...

The touring bike was frequently left on its side in the rain over-night so ample opportunity for water to get inside...

<ding, ding, ding!> I think we have a winner! 

Tim, it sounds as if water has ample opportunity to gain entry to the lamp assemblies during washing and while touring if the bike is other than upright. This would be especially true if the water was under pressure, as from a hose stream.

Hmm.

Have you considered fitting the lights with a little "shower cap" during cleaning? Seems to me a plastic sack secured with a rubber band would go far toward preventing water ingress and could be removed easily afterwards.

Possible long-term solutions might include fitting an Edelux, which seems to have much better water sealing, or perhaps using a Click-Stand to keep the bike upright when at rest, rather than laying on its side.

<nods> Yep; I'd suggest checking the hub output as well, but I now think it is more likely water is causing the problems.

Best,

Dan.

[tt2cycletours]

Yes, I have been reusing same cabling when I can and I have been earthing through the frame.  Seemed smart at the time.  From other posts I realise this is not a good idea and have changed this on the tourer.  Will now change the wiring on the commuter as well, and follow advice for washing.

Do please point me to a forum thread but can you suggest the best/sensible way to connect cable to allow removal of fork from frame.  Is the item below an overkill?  Looks it although I am happy to build stuff which will last for years and be very dependable.

http://www.rosebikes.co.uk/article/supernova-gold-contact-connector-set/aid:489129

Thanks, Tim

[Danneaux]

Hi Tim!

The Supernova connector set you linked to is very good indeed, and has received favorable reports from our own JulK and JimK.

I preferred a more compact yet still very sturdy solution, so have settled on Dean's R/C connectors, intended for model airplanes, cars, and such They make a very secure connection that is easy to part deliberately and they are well sealed against water thanks to tight tolerances and gold-plated terminals. They have proven very dependable in extreme expedition use for me. They have twin leads, so the hot and ground wires dis/connect in one go and they're really small. Pictures and details here:
http://www.thorncycles.co.uk/forums/index.php?topic=3896.msg17113#msg17113
http://www.thorncycles.co.uk/forums/index.php?topic=3035.msg27515#msg27515
More photos of my setup appear early on in my Danneaux's Sherpa ...
http://www.thorncycles.co.uk/forums/index.php?topic=3896.0
...and Danneaux's Nomad galleries as well: http://www.thorncycles.co.uk/forums/index.php?topic=4523.0

The Supernova connectors are great and also extremely reliable -- just a bit large for my needs and I wanted to disconnect both leads at once, so I went for the Dean's. Yes, wiring for a ground lead will add greatly to reliability versus earthing through the frame.

Hope this helps.

Best,

Dan.

[il padrone]

Thanks - I usually wash the bikes upside down, so ample opportunity to get water inside; I usually hose down to rinse.

It may seem a strange question to you, but why do you need to wash your bike upside down? I would never do this, always wash the bike standing on its wheels or on a workstand. Hosing is always something to be done with great discretion - again upright, always only low pressure, and directed away from sensitive parts like wheel hubs, bottom bracket, Brooks saddle....... and dynamo lights. It's not so hard to exercise this care.

As for camping, I would never leave the bike lying on its side overnight, especially not in rain. Stand it up, lean it against a tree, wall, or better stil under a shelter. My bikes have kickstands on them to ensure they remain standing, even when there is no easy support.

Just my tips.

[jags]

and good tips they are,you would never turn your car upside down to wash it
this is a great thread i've been trying this years to get Dan or Andre to make a video on how to do this the right way .i'm one of these geeks that need to be shown how to do things, crap at reading in one ear and out the other.
to late for Dan to make it but Andre would be as good i reckon even better as he's the other genius on the forum besides dan is heading off on a bit of a tour next week.
bike mechanics are useless at showing stuff like this  as they see it as there job so couldn't be bother showing.imho
i'll get slapped for that comment but so what i'm right.


jags.

geek of the week.

[Andre Jute]

and good tips they are,you would never turn your car upside down to wash it
this is a great thread i've been trying this years to get Dan or Andre to make a video on how to do this the right way
jags.
geek of the week.

Wash a bike? Come on, Jags! Dirt doesn't dare adhere to my bike! I wipe my bike down with soft cloth every second or third year, whether it needs it or not, but that's just to preserve the lifetime guarantee, which states it should be washed and waxed at least once a year.

Nah, I'm waiting until Dan comes with his chamois and his toothbrush to do a proper job for my bike's tenth birthday, then I'll video it and sell the video to geeks for €9.99.

[Danneaux]

Nah, I'm waiting until Dan comes with his chamois and his toothbrush to do a proper job for my bike's tenth birthday, then I'll video it and sell the video to geeks for €9.99.

All the best,

Dan.