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Super Moderator UK 2002 SLK320 Blue
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Discussion Starter #1
On a special visit this evening seeing my ill relative and my wife, I fell in with a debadged black R171 with the partial registration LR05 *** going through Reigate. I followed the same SLK all the way up the A217 to Burgh Heath and Drift Bridge where I went one way and the SLK went the other. I'm not sure they clocked that I was another SLK.

Have to say. I hadn't realised quite how much the LED rear lights flickered on one of these. Quite distracting! :surprise:
 

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Administrator 2009 SLK 55 AMG/Founding Member 2006
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Super Moderator UK 2002 SLK320 Blue
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Discussion Starter #3
Flicker? did they have John's 3rd brake flasher?
No. Just poorly designed rear lights.

As you know, most cars with LED rear lights double up their use as combined rear and brake lights by flashing the LED driver on and off with different on/off ratios (known as the mark/space ratio). A low on/off ratio is used for just rear lights and a high on/off ratio is used under braking. Most people cannot see the flashing LEDs and to them the light just looks 'normal' or 'bright'. If the driver frequency is too low (Audi / Mercedes (apparently) / Maserati / Range Rover / Citroen etc...) then all I see is a flashing red light. Very distracting if seen out of the corner of ones' eye as you are drawn to it away from the road ahead....
 

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Administrator 2009 SLK 55 AMG/Founding Member 2006
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if it was on a video, it is normal for them to appear flashing
so it was not on a video? wow.
 

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Super Moderator UK 2002 SLK320 Blue
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Discussion Starter #5
if it was on a video, it is normal for them to appear flashing
so it was not on a video? wow.
It's me, Jeff. I'm funny that way. I've only met a handful of people who have this same problem. :frown::nerd:
 

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Super Moderator UK SLK 55 AMG 2007
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It's me, Jeff. I'm funny that way. I've only met a handful of people who have this same problem. :frown::nerd:
You are not alone.

I sometimes find BMWs and Vauxys have a similar issue.

Generally limited to the ones in Battenberg colours.



In the US I think black and white cars suffer too!

 

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Premium Member 2012 SLK55 AMG
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Wow indeed! I've only ever seen the flashing on dash cam footage! I believe that is caused by an unfortunate relationship between between the frequency of the lights and the frame rate of the camera (30fps is common). Must surely mean that your eyes and brain are wired differently to the lay person to see this difference or the one you saw had an electrical fault.

Do all R171s look like this to you?
 

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Registered 2009 SLK200
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Thats a first for me to here .

Id imagine got to be a fault on rear lights ?
As never seen flicker on the 171s

Camera footage is well known .
 

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Super Moderator UK 2002 SLK320 Blue
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Discussion Starter #9
Wow indeed! I've only ever seen the flashing on dash cam footage! I believe that is caused by an unfortunate relationship between between the frequency of the lights and the frame rate of the camera (30fps is common). Must surely mean that your eyes and brain are wired differently to the lay person to see this difference or the one you saw had an electrical fault.

Do all R171s look like this to you?
What can I say? I do notice this on a large number of cars - but I've not seen many R171 SLKs in the dark to say for certain. If it's visible on camera footage then the effect is likely widespread. If you can count the flashes per second on the camera footage then the SLK lights are flashing at a rate equal to the camera frames-per-second plus or minus the number you've counted. The same happens with some DRLs too.

And don't get me started on the internal LEDs The BMW I have is littered with them and they ALL flicker! Really, really annoying whenever you move your head you see a trail of on/off lights that dance with the movement of your head. Maybe I should drive at night with my eyes closed.... :grin:

You are not alone.

I sometimes find BMWs and Vauxys have a similar issue.

Generally limited to the ones in Battenberg colours
Funnily enough, non-Battenberg BMW rear LEDs have not suffered from this since... I don't know when! My old 530D had LED rear lights and no flicker! I haven't noticed my new BMW flickering either.

Thats a first for me to here .

Id imagine got to be a fault on rear lights ?
Nope - the fault, if any, is in the cheap design of the LED drivers. Genuinely, the vast majority of people can't see this. I'm kinda cursed with the effect and believe me, it's more of a curse than a blessing! :(

If the right LED drivers were selected during manufacture then I wouldn't see it. But I expect that would cost slightly more.
 

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Registered 2009 SLK200
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What can I say? I do notice this on a large number of cars - but I've not seen many R171 SLKs in the dark to say for certain. If it's visible on camera footage then the effect is likely widespread. If you can count the flashes per second on the camera footage then the SLK lights are flashing at a rate equal to the camera frames-per-second plus or minus the number you've counted. The same happens with some DRLs too.

And don't get me started on the internal LEDs The BMW I have is littered with them and they ALL flicker! Really, really annoying whenever you move your head you see a trail of on/off lights that dance with the movement of your head. Maybe I should drive at night with my eyes closed.... :grin:



Funnily enough, non-Battenberg BMW rear LEDs have not suffered from this since... I don't know when! My old 530D had LED rear lights and no flicker! I haven't noticed my new BMW flickering either.



Nope - the fault, if any, is in the cheap design of the LED drivers. Genuinely, the vast majority of people can't see this. I'm kinda cursed with the effect and believe me, it's more of a curse than a blessing! :(

If the right LED drivers were selected during manufacture then I wouldn't see it. But I expect that would cost slightly more.
Mmm im on the road often but at night not so often as such .
Will keep an eye out or follow my mates slk's in the evening and look for this flickering etc

Is it under braking it shows more or just even with side lights on .??

And we are talking about just using your eyes yes .?

Not the camera / footage !!
 

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Super Moderator UK 2002 SLK320 Blue
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Discussion Starter #12
Mmm im on the road often but at night not so often as such .
Will keep an eye out or follow my mates slk's in the evening and look for this flickering etc

Is it under braking it shows more or just even with side lights on .??

And we are talking about just using your eyes yes .?

Not the camera / footage !!
Just with my naked eye. No gimmicks, no trickery, no cameras, no braking.

I notice it more when I catch the lights in my peripheral vision, so (shock horror! :surprise: ) let your mate overtake you! It also shows if I'm scanning the road ahead. I see the flickering lights as my eye passes over a car with these lights.

There's a couple of threads about this here on a non-car forum and here on Pistonheads.
 
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