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Discussion Starter #1
I emailed Bellacorse, but they didn't know the answer...
http://www.bellacorse.com/bcc169.htm

If I'm using all LED turn signals with this flasher relay, can I get away with NOT using in-line resistors?
I'll be using the NB LED idiot light conversion, also (I read that it could be a problem if the signal indicator was incandescent).
 

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With that relay you shouldn't need additional load resistors.

The NB idiot light conversion comes with bipolar LED's, so the problem usually found with the warning lamp is solved.
 

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See the note on the website about the indicator lamp diode conversion - included with that relay
NOTE - CARBURETED BIKES ONLY: The stock dash panel incandescent bulb is not compatible with LED indicators. It requires either removal or conversion to a LED bulb (supplied) and additional diodes (not included) to be wired-in. Conversion instructions are included with flasher. EFI bikes do not require the dash panel bulb to be replaced and/or diodes to be installed.
There are some mixed messages in that note:
You can do one of three things
1) Ignore the stuff that comes with the relay and install the BiPolar LED from NB
2) If the LED that comes from BC is NOT BiPolar and you use it, then you MUST rewire for diodes
3) With diodes, does not matter whether you replace indicator lamp with LED, you can retain the incandescent if you choose.

Resistors should not be required as long as you change the indicator lamp configuration, provided that specific relay will operate down the total current drawn to your actual turns. It would be nice if they provided the specs for its current operating range. Here we are concerned not with how MUCH current it will switch, but how little it will successfully switch.
 

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Here we are concerned not with how MUCH current it will switch, but how little it will successfully switch.
The brand and model have been erased off on BC's site but I think the relay is a K&S 24-0005. If so these are the specs:

Maximum operating voltage: 16v
Minimum operating voltage: 8v
Maximum operating amperage: 15a
Minimum operating amperage: 0.1a

http://www.kandstech.com/index.php?page=relays

 

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EF,

What the original poster did not mention was he wants to run three (3) sets of LED indicators (which is why he got the answer from me that he did). Of course, with the traditional two (2) pairs, no resistors are needed. One carb'd bikes, the incandesent stock dash panel light will have to be removed -or- replaced with an LED bulb with diodes which is why I include a LED bulb with the flasher. *EFI bikes already have LED idiot lights. [* I've been corrected: Only bikes with the digital odometer in the speedo have LED's.]

I have no idea what these NB idiot lights are, so that's an unknown (for me at least).

And yes, it's a K&S flasher. I photographed the back side w/o writing as I tend to do with any branded parts (I'm not much of a Photoshop guy).

/M
 

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Discussion Starter #9
Yes, in the email I asked about 3 pair of signals... I figure, it would create more of a load, which would be a good thing. If I can't get all 3 pair working, I could use one pair as running lights (since they are already mounted and whatnot).
Either way, I ordered the flasher, so I'll report back if/how it works. Thanks for the replies.

The NB idiot lights are these:
http://www.newbonneville.com/html/idiot_light_conversion.html

I bought them, but have not yet installed them.
 

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.... Of course, with the traditional two (2) pairs, no resistors are needed. One carb'd bikes, the incandesent stock dash panel light will have to be removed -or- replaced with an LED bulb with diodes which is why I include a LED bulb with the flasher. ...
Certainly mean no discredit to you or your services - just trying to clarify some possible misconceptions:

1) you cannot say carte blanch that with two Pairs of LEDs that no resistors will be required with your (Kisan) relay - if the total load per side is less than 100mA, it will likely be incapable of switching that low of a current; many LED turns can be as low as 20-30mA - in which case even three (per side) would only total 90mA
All LEDs are not created equal - the higher current ones will have no problem, lower current ones may/will.
Three is certainly better than two, as it means it has more likelihood of getting over the 100mA lower limit than with two i.e. your logic is backwards to say you know it will work with two, but not necessarily with three. There is more likelihood will work with three than two. i.e. lower current is a potential problem, higher (in this case) is not. You can also say with absolute certainty that if you know that the specific LEDs that are going to be used will work with only two, that it will definitely work with three.

2) A polarized LED indicator without diodes is no better than incandescent; indeed the LED is not actually required, however the diodes ARE i.e. you can retain the incandescent but you must fit the diodes.

I would personally not fit even a polarized LED indicator without the diode mod, as without it, it will reduce the effective voltage/current to the actual Turn Signals as it puts the indicator in series with the turn across the actual supply voltage; with diodes, it goes in parallel so you get the full spec voltage/current to the Turn Signal.
 

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Discussion Starter #11
Well, last night I swapped the signal idiot light with an LED one, and all 3 sets of signals work as expected. But, I'm using one pair of resistors up front (for 2 sets of signals), and they are sloppy- no room in the headlight for them.
When the Flasher Relay arrives, I'll try it without the resistors to hopefully cleanup the wiring. Now, I'm in no rush since I have working signals, so this may become a winter project.
 

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EF,

EFI bikes already have LED idiot lights.

/M
That is simply not true. So far I have owned 2 EFI bikes, a 2008 America and the 2010 SE I have now. Both had incandescent idiot lights when I had them from new.

I think what you mean is, bikes with the VDO digital speedo already have LED idiot lights.
 

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Ripper,

Hmmm, I was looking at a Thruxton and could have sworn it was equipped with little LED's on the clocks. No jeweled lens over incandesent bulbs. Maybe it's a Thrux/T100 feature as part of the tach package?

Or maybe once again I'm full of sh!t? :D

/M
 

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Ripper,

Hmmm, I was looking at a Thruxton and could have sworn it was equipped with little LED's on the clocks. No jeweled lens over incandesent bulbs. Maybe it's a Thrux/T100 feature as part of the tach package?

Or maybe once again I'm full of sh!t? :D

/M
Yes, these are the VDO clocks. The idiot lights for oil, high beam, turn signal and neutral have been moved to the tach, and are all LEDs. This change, to my knowledge took place in 2011 (or perhaps late 2010). However the change to EFI was in 2008, so between those years EFI bikes were fitted with the mechanical speedo and incandescent idiot lights. The VDO clocks are easily recognised by their white face (although there have been some black) and the LCD display on the speedo, and bikes which have these clocks are also eqipped with CANbus (sort of).

I didn't mean to imply that you were full of anything, I simply wanted to point out that an EFI bike does not neccesarily have LED idiot lights. Knowing this could avoid some technical problems if you are for example, supplying LED turn signal kits.:D
 

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Sorry to belabour this - just attempt to explain further

With the traditional incandescent indicator lamp, the circuit looks like below:



You can see that when left side is selected, current flows in parallel path to both the left-front and left-rear turn signals;
but also connects in another parallel path, which is through the indicator lamp and THEN through the two right-side lamps (in parallel) to ground.

The reason that the indicator lamp lights, but the right side turns do not, is because the resistance of the small low wattage indicator lamp is >> (very much greater) than the two incandescent turn signal lamps in parallel. So the applied voltage gets 'divided' between the indicator lamp and the two opposite side turns, but is not divided equally because of that resistance difference. So the voltage across the indicator lamp is much larger, sufficient to illuminate it, while the turns stay off (even though there is actually current flowing through them) i.e. X V >> Y V

Now - when you change to LED turns, things change quite dramatically - LEDs have very high resistance compared to a bulb (even a small wattage one) which is why they draw very low current. Now, when you look at the equivalent circuit above, since the opposite-side Turn signals now have very high resistance compared to the indicator, most of the voltage will be developed across those
i.e. Y V >> X V - so now it is the opposite side turns that light instead of the indicator.
The result is that both sides will flash - like emergency flashers - regardless of which side is selected by the switch.

Now - if you simply replace the incandescent lamp with a non-polarized LED (current flows in either direction)* then you STILL get a voltage divider situation between the Indicator lamp and the Turns - so you will most likely still get the opposite side turns at least glowing.

The way to resolve is to install a couple of diodes to isolate each side from the other.



The diode allows current to flow forward through it, but not in reverse (same as LED, which is just a diode which gives off light).
So while the one diode allows the indicator be in parallel circuit, the other diode blocks the current from flowing through the opposite side Turns. And of course each diode performs the opposite function when other side is selected by switch



* There is no such thing as a bi-polar LED - included in the LED packaging are conventional diodes which are connected such that regardless of the polarity of the applied voltage, the positive is always routed to the anode of the LED. It can also be simply two LEDs connected in parallel in opposite polarities such that it either conducts through one or the other.

Some general notes:
A low wattage bulb (indicator lamp) has higher resistance than a high wattage turn signal lamp
Two turn signal lamps in parallel have half the resistance of a single turn signal lamp.
So Indicator lamp has >> (very much greater) resistance than two Turn Lamps in parallel.
An LED has >> resistance than an incandescent lamp and draws << current.
 

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The way to resolve is to install a couple of diodes to isolate each side from the other.


This mod worked beautifully. One try and done. Thanks so much for posting it, DEcosse.

I'm running LED turn signals (Lazer Star XS) and LED idiot lights, with an LED-appropriate flasher. With the LED idiot light, my signals would blink correctly but the idiot light would not light. With an incandescent idiot light, all four signals would flash regardless which direction was engaged. The diode mod enables the LED idiot light to flash properly. I didn't try it with an incandescent idiot light.

FYI, as DEcosse posted elsewhere, a Thruxton's high-beam ground is not a black wire, but a brown one.
 

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Sorry to belabour this - just attempt to explain further
I'd guess the indicator LED still has a higher effective resistance than the turn signal LED. The indicator is designed to operate at a lower current than the turn signal, so it would seem to have a higher resistance. In that case, the indicator still gets the bulk of the voltage and operates as desired.

A problem might occur, though, with the off-side turn signals. Unlike an incandescent lamp, which at low currents doesn't get hot enough to make the filament glow, an LED emits light whenever it's carrying current. Will that light make it appear that the off-side signal is on?
 
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