Connect with us

Help with LED indicators/turn signals

Discussion in 'LEDs and Optoelectronics' started by stuart cox, Feb 17, 2018.

Scroll to continue with content
  1. stuart cox

    stuart cox

    17
    0
    Feb 17, 2018
    Hi there

    I'm hoping someone can help me please!

    I am building a custom motorcycle which is based on a ducati motorcycle.

    The indicator/turn signals on the Ducati have a permanent live feed with the relay providing a pulsed negative contact when switched on (hope that makes sense!). I am trying to fit a Yamaha rear light with integrated rear indicator/turn signals. The problem is that Yamaha work the opposite to the Ducati, the indicator/turn signals have a permanent negative with the relay providing a pulsed positive feed when switched on.

    The Yamaha rear tail light/brake stop light and indicators all have a shared earth/negative so I can not make any changes to the permanent negative feed to the indicator/turn signals. The ducati relay is built in to the dash so I can not make any changes there either!

    My question is - is there a simple circuit or relay that I can add that would allow me to switch the polarity somehow?? to make this set up work?

    I hope I have explained this well, if not I can hopefully answer any questions!!

    Thanks in advance
    Stuart
     
  2. Harald Kapp

    Harald Kapp Moderator Moderator

    11,444
    2,629
    Nov 17, 2011
    Welcome to EP, Stuart

    You could use the dashboard relay to activate an intermediate relay with the coil wired like the Ducati lamps (switched negative) and the contacts wired for controlling the Yamaha lamps (switched positive).

    Why can't you make changes there? Simply connect plus to the relay input and the switched output will have a switched plus suitable for the Yamaha lamps. Provided the circuit in the dashboard really is a relay, not an electronic circuit which would not tolerate a reverse polarity at the input.

    What model do you have? I looked up a few circuit diagrams on the internet and those seemed to have minus as the common potential and switched plus. As would be suitable for the Yamaha lamps.
     
  3. stuart cox

    stuart cox

    17
    0
    Feb 17, 2018
    Thanks for Harald your welcome and your reply!

    'You could use the dashboard relay to activate an intermediate relay with the coil wired like the Ducati lamps (switched negative) and the contacts wired for controlling the Yamaha lamps (switched positive)'

    This is the option I was leaning towards and I guess probably the simplist solution? I would need a relay for each side though which there is probably just enough room to squeeze in.

    'Why can't you make changes there? Simply connect plus to the relay input and the switched output will have a switched plus suitable for the Yamaha lamps. Provided the circuit in the dashboard really is a relay, not an electronic circuit which would not tolerate a reverse polarity at the input.'

    Unfortunately the relay in the dash is inaccessible so I can not make any changes to this.

    'What model do you have? I looked up a few circuit diagrams on the internet and those seemed to have minus as the common potential and switched plus. As would be suitable for the Yamaha lamps.'

    The Ducati model is a Hypermotard 796 2010. I have tested the output wires to the rear signals and once the ignition is switched on they have a constant live feed. I also connect a bulb directly between the positive of the battery and the negative side of the signal wiring, then when the signal switch is operated the bulb flashes correctly. Therefore I assume that they must have plus as the common potential and a switched minus?

    Thanks again
    Stuart
     
  4. Harald Kapp

    Harald Kapp Moderator Moderator

    11,444
    2,629
    Nov 17, 2011
    I do think it is rather unlikely that this model is so different from other models when it comes to the wiring. Unfortunately the manuals for this bike available online are not free.
    Although your question is electronics related, you may be better off asking on a Ducati forum, e.g. this one?
    If you can get hold of the wiring diagram, you could upload it here for inspection and further advice.

    If the Yamaha tail light assembly is insulated from the bike's chassis, you could simply connect the Yamaha's common to the Ducati's common regardless of polarity - provided Yamaha uses incandescent lamps, not LEDs.

    Cheers,
    Harald
     
  5. stuart cox

    stuart cox

    17
    0
    Feb 17, 2018
    I know what you are saying, it is a bit strange! I have a CD manual for the bike but the wiring diagram section takes me to a link which I guess is out of date as it no longer works. I will try a Ducati forum later, thanks for the link!

    The Yamaha rear light is LED and a sealed unit, also the turn signals, tail light and stop light all share the same negative/earth wire, so no alterations can be made here either!

    However I have just wired in a couple of relays with the Ducati signal wires powering the coils and the Yamaha light positive feeds and a separate ignition switched positive feed to the switched circuits of the relays and it works perfectly!

    My only concern with this set up is if the relays will cope with the constant switching on/off when the turn signals are switched on?

    Thanks
    Stuart
     
  6. Harald Kapp

    Harald Kapp Moderator Moderator

    11,444
    2,629
    Nov 17, 2011
    That'l depend on the relay. A good relay lifes up to some 2*10^7 switching cyles.
    Let's assume the flash frequency of your indicators is 3 Hz.
    Let's furthermore assume the average on time of the indicators is 10 s (less for changing lanes, more for taking a turn).
    And let's assume you operate the indicators 200 times a day on average.
    This adds up to 6000 switching cycles per day.
    Under these conditions a relay with 2*10^7 switching cycles will operate for 3333 days or 12.5 years - not taking into account harsh weather days, winter etc, when the bike rests in a cozy garage.

    A spezialized automotive flasher relay may last even longer.

    Note the above number are my gut feeling. Many drivers spare their relays the torture by not activating the indicators at all :(.
     
  7. stuart cox

    stuart cox

    17
    0
    Feb 17, 2018
    Wow.....thanks for working that out! I wouldn't know where to start!
     
  8. stuart cox

    stuart cox

    17
    0
    Feb 17, 2018
    Ok, new problem now.........when I start the bike and the engine is running, the turn signals start to pulse rather than flash. When the engine isn't running they flash perfectly at normal rate?

    I have fitted 10w load resistors to the rear signals because I have changed them from 10w incandescent bulbs to LED. The front orignal LED signals have been replaced with other LED signals which have a 7w rating, so I haven't fitted any load resistors.

    I'm wondering if the original front LED signals are a different wattage to the new ones and that is throwing the dash flasher?

    Apparently the dash of the bike sends the flash to the signals so there is no relay. I'm thinking that when the engine is running, the stator is putting out around 14v, where as with the engine off the battery would probably put out 12.6v or something like that, so maybe this increase in voltage when the engine is running is somehow causing the pulsing problem!?

    I know this is probably a question for a motorcycle forum, but it's an electrical problem and I would probably have more faith in this forum to be honest!

    Thanks Stuart
     
  9. Harald Kapp

    Harald Kapp Moderator Moderator

    11,444
    2,629
    Nov 17, 2011
    That shouldn't be necessary as the relays are electromechanical and should work with the lower load of the LEDs, too.

    Does the pulsing change with engine RPM? At low RMP there is possibly a lot of AC ripple on the 12 V supply which is less noticeable at higher RPM. In that case an additional filter between the tail lights and the relay may offer some remedy. Such filters are offered e.g. for car audio systems.
    Note this is just a guess - I do not have personal experience with this kind of problem.
     
  10. stuart cox

    stuart cox

    17
    0
    Feb 17, 2018

    Thanks again for your reply Harald.

    Unfortunately the flash doesn't come from an electromechanical relay, it is a circuit built in to the dash that produces the flash I have been told, therefore the need to try and match the wattage of the original bulbs/leds. Apparently it is quite common to do this when switching from bulbs to Leds to stop what they call hyper flash (rapid flash rate of the signals)

    With your knowledge, are you able to work out what size resistor I rould need to reduce a load of 7w to 3.11w? It would be much appreciated! That way I should be able to perfectly match the original signals power draw.

    Many thanks
    Stuart
     
  11. Harald Kapp

    Harald Kapp Moderator Moderator

    11,444
    2,629
    Nov 17, 2011
    Why reduce? I understand you need to increase the power dissipation.
    Increasing power dissipation is easy, simply put a resistor in parallel to the small load.
    Reducing the power dissipation is critical as you need to put a resistor in series with the load. This will in turn reduce the voltage across the load and the lights may not work at all.

    You replaced front and rear lights, right? What happens, when you, only temporarily, replace one of the lights with the original tungsten bulbs?

    Another point here: I understand you added an auxiliary relay between the flasher circuit in the dashboard and the light. Therefore the flasher circuit doesn't "see" the lights, whatever type (LED, tungsten) they are. Therefore the wattage of the lights should be completely irrelevant. If, as you've been told, the flasher circuit in the dashboard expects a certain minimum load, then you will have to add this load across the coil of the auxiliary relay. Simply try this by connecting a 10 W light bulb parallel to the coil of the auxiliary relay.
     
  12. Bluejets

    Bluejets

    4,770
    999
    Oct 5, 2014
    Older style blinker units operated on having a certain load.
    Remove part of this load, say with a blown bulb, and the remaining bulb would flash in short cycles.
    Same affect could be had from adding a trailer/ caravan to a car flasher system.

    Fix was to replace the flasher unit with a solid state unit.
    These do not operate on loading.
     
  13. Harald Kapp

    Harald Kapp Moderator Moderator

    11,444
    2,629
    Nov 17, 2011
    Good idea, but if Stuart had access to the flasher unit in the dasboard in the first place, he wouldn't have top resort to the auxiliary relay to invert polarity.

    What else is not quite consistent with this theory at all, however, ist the fact that running on battery alone the flasher works as expected, only with the engine running the pulsing effect happens. This makes me think the issue will not be solved by simply adding an additional load.
     
  14. Bluejets

    Bluejets

    4,770
    999
    Oct 5, 2014
    There is some info out there in Ducati forums saying the flash is determined by a dash micro. Apparently it can be reprogrammed or fit a 47R 10w resistor. Couple of other possibilities also.
     
  15. stuart cox

    stuart cox

    17
    0
    Feb 17, 2018
    Thanks for your replies!

    Just to recap, the original signal setup on the bike is FRONT - 3.11w LEDs REAR - 10w Bulbs

    The new set up is FRONT - 7w LEDs REAR - LED's with 10w load resistors, also the rear LEDs have reverse polarity to the original bulbs, so I have fitted a couple of intermediate relays to rectify.

    The dash micro supplies the flash.

    The issue - when the turn signals are operated with the engine off (ignition switch on) they all flash correctly. when the engine is started they start to pulse instead of flash, the pulse is also a little inconsistent.

    What I have tried so far - I have put a 10w standard bulb in place of the rear led/resistor and exactly the same happend as above, so no change there.

    I have also put a standard bulb in place of the front LEDs again same as above, pulsing when engine running.

    I have yet to try a load resistor to the front signals, but I'm pretty sure that will do nothing because as mentioned I have tried connecting a 10w bulb to the front which also changed nothing!

    I also took out the load resistors to the rear signals and that created a Hyper flash (signals flash really quickly) which is expected when replacing bulbs with LEDs apparently.

    One other thing I have tried is changing the positive feed to the auxiliary relays directly to the battery, instead of the positive feed I took from the fusebox, which is ignition switched, again this changed nothing.

    The only thing I can think of is that I need to match the original watts front and back. The 10w load resistors at the rear should be matching the original 10w bulbs, but the front LEDs are 7w and the originals were 3.11w, so I don't know how to match these?

    'There is some info out there in Ducati forums saying the flash is determined by a dash micro. Apparently it can be reprogrammed or fit a 47R 10w resistor. Couple of other possibilities also.'

    Thanks Bluejets, I have tried this but unfortunately my model doesn't have the reprogramming function.

    If, as you've been told, the flasher circuit in the dashboard expects a certain minimum load, then you will have to add this load across the coil of the auxiliary relay. Simply try this by connecting a 10 W light bulb parallel to the coil of the auxiliary relay.

    Harald, I wired the 10w load resistors across the rear signal feed wires which then power the coils of the auxiliary relays. This should be doing the same thing as connecting a 10w bulb across the coils?

    Thanks
    Stuart
     
  16. stuart cox

    stuart cox

    17
    0
    Feb 17, 2018
    I have also just tried putting a 10w bulb directly to the rear signal wires (cutting out the auxiliary relay and load resistor) The signals flash correctly with the engine off but Hyper flash (flash quickly) when the engine is running!

    This leads me to believe the issue is with the front LEDs as they are the only changed element in this scenario.

    Although it is interesting that they didn't have the pulsing issue, instead hyper flash with this set up!?
     
    Last edited: Feb 21, 2018
  17. Harald Kapp

    Harald Kapp Moderator Moderator

    11,444
    2,629
    Nov 17, 2011
    Right.
     
  18. Harald Kapp

    Harald Kapp Moderator Moderator

    11,444
    2,629
    Nov 17, 2011
    Cross check with the original lamps atthe front instead of the LEDs. Still the same effect?
     
  19. stuart cox

    stuart cox

    17
    0
    Feb 17, 2018
    I really wish I could do that, but I don't have the originals anymore!.... although I do have another bike of the same model I could maybe remove them from and try!....
     
  20. stuart cox

    stuart cox

    17
    0
    Feb 17, 2018
    Ok, so I have just tried an original signal on the front and everything works fine with the engine running, I also noticed that when I unplug the new 7w front signals completely, the rears flash correctly even with the engine running!

    I'm thinking that the dash micro (if that is the correct term?) has a maximum load tolerance as well as a minimum load tolerance and because the new front signals are 7w as opposed to 3.11w (the originals) this is confusing the dash micro?
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-