Need help with LED flashers.

[DJ Downunder]

Last week I bought some nice looking new small LED turn indicator lights for my 02 R1150R and I put the front ones on first and they worked fine except they flashed a little fast but I was cool with that and thought once the rear was fitted it would come good.. But.. Once I fitted the rears nothing seems to work right.. They blink once and stop and only one side works and only when the motor's running.. Bugger!

I've had the back of my bike apart and together a few times now trying to work out what's wrong.. After a quick search on the net I found fitting them is not so easy and BMW have changed things in the wiring from the R1200R onwards to allow leds to work.. And then I read something about the Can Bus (whatever that is) and maybe I need a replacement bit of wiring loom to make them work?... Has anyone else fitted them to their R1150R and can help me to get mine working?... Thanks.

David

[Sunbeemer]

Hi DJ. Good to hear you're still riding.
The only thing I can offer in the way of real help is I don't believe our bikes (2002) have the CAN-BUS system, so I don't think that's the problem. I'm guessing that the LED's are drawing too little current to cycle the timer circuit in the flasher module. I think some LED's incorporate a resistor to compensate for that, making them draw as much current as a bulb. Do yours?

[towerworker]

DJ--
From what I understand the r's lighting system is looking for a specific current draw so it thinks all the bulbs are burning. When that current draw is less than whatever value is preset in the computer then the computer interprets that as a failed bulb somewhere. Since led's draw substantially less power than conventional bulbs the system will think there is a blown bulb somewhere hence the crazy operation.
What will probably be necessary is a resistor added to each new signal bulb to bring the current draw back up to the value the computer is looking for. Some info is needed to figure the value of that resistor to be added:

1. current draw of old bulbs (per bulb)
2. current draw of new led bulbs

This resistor arrangement really should already be built into the replacement led light---if not (and obviously it isn't) then some cutting and splicing and potentially soldering may be necessary.
If you can get me the electrical specifications on your led's then I can figure the resistor values you will need.

Wayne

[Matt]

You can get a solid state relay that does not work on current drawn from the bulb.
I have used one of these successfully.

http://www.acumen-electronics.co.uk/cat ... ays,b.html

Or

http://www.puig.tv/tuning-bikes/turnlig ... 71en/f389/

[Hottech]

I had the same problem and solved it with buying a Kisan Signal Minder. www.kisantech.com/ It is a simple plug and play relay that you switch your stock relay with the Kisan. Works like a charm and you can set how long you want your blinkers to blink.

[Airman]

DJ--
From what I understand the r's lighting system is looking for a specific current draw so it thinks all the bulbs are burning. When that current draw is less than whatever value is preset in the computer then the computer interprets that as a failed bulb somewhere. Since led's draw substantially less power than conventional bulbs the system will think there is a blown bulb somewhere hence the crazy operation.
What will probably be necessary is a resistor added to each new signal bulb to bring the current draw back up to the value the computer is looking for. Some info is needed to figure the value of that resistor to be added:

1. current draw of old bulbs (per bulb)
2. current draw of new led bulbs

This resistor arrangement really should already be built into the replacement led light---if not (and obviously it isn't) then some cutting and splicing and potentially soldering may be necessary.
If you can get me the electrical specifications on your led's then I can figure the resistor values you will need.

Wayne

I think you guys are on the right track. If I recall correctly, Wunderlich's replacment LED turn signals have a bridge resistor for each pair, front and back. I was concerned about the ABS system being offended when I installed my LED Brake! light assembly, but it did not affect anything.

[macx]

I've got an 04 R1150R that I added the Hyper Lites to.

I'd always thought my bike had the CanBus, but have since learned that didn't start
till the R1200's.

The HyperLites are LED's but have never had a problem with them. With such a low
current draw, I think they're run off of the existing circuit or something, don't remember
for sure. I checked on their site - they don't show a wiring diagram but things they
say suggest there may be a small controller of some sort.

The ones with a combo of running lights and flashing brake lites / turn signals do have
a separate wire for the running lights.

I just got the brake / turn signal ones so there's no confusion for following drivers
with a running light changing to brake lites / turn signals.

[Sunbeemer]

The HyperLites are LED's but have never had a problem with them. With such a low
current draw, I think they're run off of the existing circuit or something...

Yeah, I think you're right. I'd guess they're wired in parallel with your brake light, so the total current draw is the sum of the regular bulb plus the LED bulb, which is quite low so it doesn't overload the circuit or wiring.

But DJ's problem, as I understand it, is he replaced the regular bulbs with LED's so the current draw is just a fraction of what it was and needs to be to trigger the turn signal flasher.

You can use the relationship V/I = R to calculate the resistor you'd need to mimic a signal light bulb, which typically draws about 1 amp, so 12V/1amp = 12ohms. And how much power does that resistor need to dissipate? That is given by P=V X I which gives 12V X 1amp = 12watts. So you could put a 12 ohm, 12 watt resistor (a 10 ohm, 10 watt resistor would be easier to find and will work ok) in series with the LED bulb to give the flasher the same load as a regular bulb, which should trigger the flasher circuit.

[NoRRmad]

In series? In parallel, I think...

[DJ Downunder]

Thanks for the help guys.. I'll check with an auto electrician tomorrow and also suss out the SM-5 and let you know how I go with it.

David

[Sunbeemer]

In series? In parallel, I think...

Right you are, NoRRmad. Otherwise, the LED's wouldn't achieve full brightness!
Thank you. You deserve an "A".