Resolved: BMW canabus and T10 501 Wedge LED question.

Started by lenbo, January 14, 2010, 09:22:19 AM

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lenbo

Has any one been able to use a LED wedge bulb for a BMW canabus motorcycle ? I have a 2008 BMW K1200 GT and would like to add these bulbs to the bike along with the bullets.

PS: The bullets with the podmods are awesome, thanks. I'll post pic's soon.

ross219uk

Don't think so as most(all?) bikes from (from 2002 from memory) have automatic lights on and don't have sidelight bulbs anymore

Fluke

Hi most bikes from around 2002 take wedge style sidelight bulbs, but because of the ultra low power of them they will throw a CANBUS fault on modern BMWs. There are bulbs out there that get round the problem by loading up the bulb with resistors to draw more current... but I don't like this solution as it's a waste of power.

We don't stock anything at the moment, but I'm looking into it.

Glad you like the Bullets, looking forward to seeing some photos

Regards

RCE

Quote from: ross219uk on January 14, 2010, 01:34:17 PM
Don't think so as most(all?) bikes from (from 2002 from memory) have automatic lights on and don't have sidelight bulbs anymore


Even though the headlight is on by default the side light is still present on all modern bikes and will be lit also. The parking light is a legal requirement for a vehicle with a full version MOT (eg not a daylight only MOT) and the side light will be used for this function too.

martin999

Quote from: ross219uk on January 14, 2010, 01:34:17 PM
Don't think so as most(all?) bikes from (from 2002 from memory) have automatic lights on and don't have sidelight bulbs anymore


No, as RCE says, they still have the sidelight bulb(s) you just can't turn them or the dipped beam off when the ignition is on.

Like most modern cars, the CANBUS will look at the current draw of the lighting circuits.  If it is below a certain point it will flag up a failed bulb.  The LED T10s only draw 30mA compared to the 416mA that a 5W bulb will draw at 12V, so in most cases you will get a failed bulb warning.

If you want a work-around, simply connect a resistor in parallel with each sidelight bulb to mimic the current draw of a 5W bulb.  The actual value would be 28 ohm, but the nearest standard value would be 27 ohm.  As it will be on all the time, I would also over-rate the power to something like 7 - 10W just so you are not running it at full capacity which may lead to premature failure.

This is solution Dan doesn't like because you are just wasting power, but in the absence of other solutions it will work.

If the threshold for the CANBUS failed bulb was known, then you could use a resistor to take the current just over the threshold and not waste the full 5W, but I doubt you would be able to find this information.

Fluke

I wonder what the threshhold set by BMW is for CANBUS faults... there must be a spec out there somewhere.

martin999

I reckon you would be hard pushed to find the info, BMW will of course know but I doubt it would be publicly published.  You could find it by experimentation, (put a pot across the bulb terminals, adjust until the bulb failure is cleared, measure the pot and work out the current), but as canbus is just a standard, each manufacturer will probably have set different thresholds.


I'm a little surprised that 30mA isn't enough though.  My Passat (like others) will give a failed bulb warning even if the bulb isn't illuminated.  This means that they must be passing a small amount of current through the filament to make sure it's not open circuit, but not enough to illuminate it.


Sods law says that it's probably something like 50mA!  ;D

ABQbiker

I put the lights on my 2006 R1200RT with the CANBUS system and have gotten mixed results. At first the lights worked (and looked) great, no error messages on my display. After about an hour of riding I got an error / fault symbol on my display saying one the wedges was not working. Sure enough, one had burned out.

I let Bikevis know and they sent me not 1 but 3 replacement bulbs at no charge (GREAT customer service, thanks Dan!).  :)  I replaced the 1 burned out bulb and put the bike back together, however about 5 minutes into my ride I got the fault symbol on my display again.  :o  I checked the lights but they were both working...crap! Took the bike apart again and tried one of the other bulbs Bikevis sent me, same fault message on the display. Switched out another bulb and the display message cleared up, everything was fine... :D

About half hour later I got the display error message again, checked the lights and the other side was now burned out.  >:(  Tore the bike apart again and burned out the remaining bulbs before even putting it back together so I put the stock bulbs back in and put the bike back together.  :(

When I initially discussed the issue with BikeVis they believed it might be a power issue specific to my bike (voltage spikes, unstable supply, etc.). While that might be the case, I also have a set of bullets installed and not had any issues with them (really like them too!). I'm guessing they use the same LED's as the wedges and, if they are, would expect to be having the same power spike / regulation issues with them burning out.

I guess the bottom line is what others have stated, the BMW CANBUS system does not play well with the wedge lights so it's better to not use them for that specific application. Too bad, really like the way they looked on my bike  :'(

Fluke

Hi

It's a really weird problem as like you say the Bullets and Wedge LEDs share the same LED element. As strange as it sounds I've known a bad / loose connection in the bulb holder cause LEDs to blow... this was the case on my ZX10, after tightening the holders no more blowing bulbs.

I'm looking at getting some CANBUS LEDs in soon and will send some over to you to try...  will get to the bottom of this one :)

Regards

RCE

I have been reading on an Audi forum how fitting HID caused the wiper motor to burn out because they shared the same canbus supply ! I guess the noise from the ballast caused issues.


Wonder if the side light canbus shares the line with something like the fuel injection (the old tractors do have fuel injection nowadays don't they  :-X  )

Fluke

Good thinking, I bet HID ballasts create alot of spikes when starting up, you might be onto something with the 'sharing'

jdd3


Fluke

Thanks for the link, they look great and with the built in resistor to simulate the normal load error free, nice find!

RCE

Thinking this through a little further, would it be possible to make a slightly bigger bullet that took a wedge LED instead of the fixed LED as at present ?

Fluke

Thats something that I think we will do in the future... it's a much more complex design though