Author Topic: LED bulb is dimming  (Read 2091 times)

ianatstanage

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LED bulb is dimming
« on: December 08, 2020, 12:41:37 AM »
Hi,
I have a SON Edelux on my Mercury from late 2015.
I tend to ride with the lights on all the time.
This winter I have noticed that the front beam is a lot less bright compared to previous winters.
Trips in the past along unlit roads were great due to the bright beam from the Edelux.
However, now I need to be much more careful due to less light.
The SON website indicates that the LED cannot be replaced.
Various web searches also suggest that LED bulbs do deteriorate over time.
It could be my eyes (I turned 60 recently), although I don't think so!
Does anyone know if there is a way to replace the LED?
CHeers,
Ian

Danneaux

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Re: LED bulb is dimming
« Reply #1 on: December 08, 2020, 01:57:18 AM »
Yes, LED bulbs do dim over time and use. Threading dislocations in the Gallium Nitride (InGaN) that makes up the semiconductor can occur from time of manufacture than get worse over time in a nonlinear response...they dim gradually, then the loss becomes really noticeable after a certain point. White LEDs in particular seem to be vulnerable to excessive heat. If a heat sink has failed due to shock/dropping or vibration fatigue, it can "cook" an LED pretty quickly.

The best guide I've found to "what's inside" an Edelux can be found here:
https://swhs.home.xs4all.nl/fiets/tests/verlichting/koplampen/Schmidt_edelux/analyse/index_en.html

A friend's Edelux developed a loose end cap. I tightened it without causing any marks or damage using a couple of opposed rubber strap wrenches. I think they would be key to successful disassembly.

While the LED may indeed be bad, I would first check all the connections in your wiring to make sure there is no corrosion or break in the wires. This is far more likely to be the case. A voltmeter can really help and these days, are available for pretty low cost. I picked up one for free last week as a coupon "prime"/freebie at a tool store. Riding on salted roads can in time affect connection integrity as well. Excessive resistance can affect brightness and it is possible your problem is there rather than in the LED itself (fingers crossed for your good luck).

Best,

Dan.

ianatstanage

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Re: LED bulb is dimming
« Reply #2 on: December 08, 2020, 07:58:28 PM »
Thanks Dan,

Very informative and useful.

All the connections appear okay, but I will check and clean again.

The inside of the lamp looks a bit complicated for me to have a fiddle with, plus I can't find anyone selling the LED bulb.

It looks like a new lamp :-[

Ian


Danneaux

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Re: LED bulb is dimming
« Reply #3 on: December 09, 2020, 01:56:37 AM »
Quote
...I can't find anyone selling the LED bulb.
Ian, the Candlepower Forum (similar to this one in tone) is devoted to lighting and LEDs in particular. They can usually suggest sources for odd OEM replacements and occasionally improved versions! They have handled a number of queries regarding LED bike lights:

Root Directory link:
https://www.candlepowerforums.com/vb/forum.php
LED Specific link:
https://www.candlepowerforums.com/vb/forumdisplay.php?91-LED
Edelux-related queries/search results:
http://www.candlepowerforums.com/vb/google.php?cx=014400917352555993086%3A7_xzry8oxho&cof=FORID%3A9&ie=ISO-8859-1&q=Edelux&sa.x=0&sa.y=0

Those of us who collect things usually find related online fora to share and exchange views. ;) I collect bicycles, sleeping bags, tents, pads, stoves, compasses, LED lights of all kinds, tools, utility knives/multitools and Linux distros. :D

Best,

Dan.

steve216c

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Re: LED bulb is dimming
« Reply #4 on: December 10, 2020, 11:36:51 AM »
...
While the LED may indeed be bad, I would first check all the connections in your wiring to make sure there is no corrosion or break in the wires. This is far more likely to be the case. A voltmeter can really help and these days, are available for pretty low cost. I picked up one for free last week as a coupon "prime"/freebie at a tool store. Riding on salted roads can in time affect connection integrity as well. Excessive resistance can affect brightness and it is possible your problem is there rather than in the LED itself (fingers crossed for your good luck).


+1 on checking the wires first. I also ride 24/7 lights on all year round and don't trust my 50+ year old eyes for their light sensitivity any longer when actually dark- but I have been riding hub dynamo powered LED lights on mine/family member bikes for years and know that poor cabling is the biggest culprit behind most light issues I've come across.

I don't have a voltmeter but after my son (with good eyes) was complaining his not so old LED lamp was not that bright any more, I  hacked a USB cable, soldered a couple of spade connecters to the cut off end- and used a USB power  bank to test a 'faulty light' direct at its input terminals. Hey Presto, and a weak beam LED shone in brighter glory again.

I replaced the suspect cabling a few days later which looked otherwise fine with something a bit more substantial/thicker looking which resolved my son's problem. Of course there is no guarantee this resolves your light issues, but the USB powerbank test might at least prove or eliminate one possible cause.

An upside- my son used the USB cable and powerbank as temporary power source between my identifying the problem and actually fixing it. So I created an easy to make potential emergency 'get you home' lighting fix that might be useful for others with a spare powerbank and an old USB cable they might carry when cycling.  Basically making dynamo lights into temporary battery powered lights.
The USB power bank used was a cheapo 5000mah 5V affair I got free at a trade show. It lit front and rear lamps for a daily ride of approx 90 minutes and where he was down to 'one bar' by time he got home. A decent powerbank might be recommended if you planned to power dynamo lights from battery power for longer rides.
If only my bike shed were bigger on the inside...

Andre Jute

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Re: LED bulb is dimming
« Reply #5 on: December 10, 2020, 03:58:35 PM »
My first response to an apparently bad LED lamp is the same. "The LED has an MTBF --mean time between failures -- of 50,000 hours. It has to be the wiring. Now where's my DVM so I can test the continuity?"
« Last Edit: December 10, 2020, 04:32:07 PM by Andre Jute »

ianatstanage

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Re: LED bulb is dimming
« Reply #6 on: November 25, 2021, 06:53:02 PM »
Update to my post.
I think it was my eyes that were at fault!
SJS offered to send the Edulux back for testing, but I never got round to it.
During the spring and summer lighting was less of an issue.
So far this winter there have been no problems as the light appears to be working well.
'Should have gone to Specsavers' 8)
Ian