Electrical Gugus needed!

[Silent]

As some of you may know, I added LED auxillary brake lights to my bike LINK However using the LEDs alone with the brake modulator, sometimes they flash and sometimes they dont :blink: When they are not flashing and I jump across the LED wires with a standard fillament bulb, they immediatly start working, and continue to work after the fillament bulb is removed. My opinion is that I'm dealing with to low of a load to trigger the modulator all of the time. Is there a resistor I should add (and how should it be wired) to increase the load enough to trigger the modulator? I've seen the load resistors on line for about $10, but I'd rather go down to Radio Shack and just pick up a resistor and tie it in. It seems that I'm right on the bleeding edge of the required draw to trigger the modulator atm.

 

[Rogue]

If you have access to a multi meter you can test the ohms on the old lamp and get one that size. I would think 1/4 watt would be plenty. (you need ohms & watts).

 

[BrunDog]

The size of the resistor will have to get bigger as its value gets lower, because it will need to dump more energy. Resistors usually come in 1/8, 1/4, 1/2, and 1W, then go to load resistors (ceramic block) of various sizes. Your local radio crap probably has some in stock.

Pick the applicable resistor, preferably the smallest (highest value, that is) that will get the job done:

Resistance Current Power

(ohms) (amps) (watts)

1000 0.014 0.196

500 0.028 0.392

250 0.056 0.784

200 0.070 0.980

150 0.093 1.307

100 0.140 1.960

75 0.187 2.613

50 0.280 3.920

25 0.560 7.840

12 1.167 16.333

-BD

 

[Silent]

So if I'm on the edge, start with the 1k ohm resistor?

Series or parralel?

 

[BrunDog]

I didn't pay attention to your circuit. How did you wire in the bulb to get it to work, series or parallel? I assume parallel, which is what the values above are for. If you wire in series, then they don't necessarily apply, because additional voltage drop occurs in the modulator.

This sound cluster-frigged to me. Why doesn't this work as advertised? What does the manufacturer recommend?

-BD

 

[v65]

I'm no gugu, but I would guess that a call to the manufacturer would get you a value for the resistance. This is a pretty common problem for them.

 

[BrunDog]

Oops, dupe post. Please ignore.

-BD

 

[Silent]

I didn't pay attention to your circuit. How did you wire in the bulb to get it to work, series or parallel? I assume parallel, which is what the values above are for. If you wire in series, then they don't necessarily apply, because additional voltage drop occurs in the modulator.
This sound cluster-frigged to me. Why doesn't this work as advertised? What does the manufacturer recommend?

-BD

I'm using 12v Semi Truck running lights. There not designed for the FJR in any way. They light up nicely tho, link to the writeup is in first post. The modulator isn't designed for LED's either. They have one that is, but it's more $. Quick down and dirty sketch of the wiring

 

[FJRandy]

Personally, I'd rather be called a "GuRu" than a "GuGu", but I'll let it slide this time.

Here's what you''re looking for. Happy reading

EDIT!!!!

After posting my reply, I realized just what you're looking to do. The above link is not what you want to do! THIS is how you wire it. Cut the brake light wire to the taillight and put the modulator inline. THEN attach the LED leads to the brakelight wire AFTER the splice.

If you use resistors to fire the modulator on the LED's only, you'll end up with lower output from the LED's. If those 9 LED clusters will run normally at 12v, putting a resistor inline will only drop the input voltage to them, resulting in loss of output (brightness).

Hope this is the answer you were looking for. The above link is still cool to read anyway. Lot's of good info when using off the shelf LED's.

 

[Silent]

I've tried that site. You have to have an idea of what numbers to put in to get decent numbers out :blink:

I guess I'll just go out and buy the LED stoplight modulator

 

[FJRandy]

I guess I'll just go out and buy the LED stoplight modulator

NO YOU DON'T HAVE TO!!!!

Read my last post carefully. All you have to do is cut into the brakelight wire and "T" off the LED pos wires between the modulator and taillight.

 

[twistedcricket]

I guess I'll just go out and buy the LED stoplight modulator

NO YOU DON'T HAVE TO!!!!

Read my last post carefully. All you have to do is cut into the brakelight wire and "T" off the LED pos wires between the modulator and taillight.

I like the idea, but would I need a Stoplight Modulator to make this all work? I was just going to add LEDs for brake and separate LEDs for turn. I was originally thinking I could just splice into the power of the brake/turn lights and be ok? Or am I off my rocker?

 

[ionbeam]

In a previous post Silent said that he was only running extra LEDs with the modulator, he didn't want the brake lights to flash, so cutting the brake light wire isn't an option.

Misc. electrical ramblings --

LEDs come in two types -- one with a built-in (internal) power dropping resistor and the other without, requiring you to install a resistor. Running LEDs that need an external resistor *without* the resistor will lead to dead LEDs PDQ because they need the resistor to reduce power. If Silent has had the LEDs on for any length of time and they still work it is a sure bet his LEDs contain an internal resistor.

Silent has said that his modulator specifically warns WILL NOT WORK WITH LEDs. There are many different electronic solutions to supply power to lights, many are dependent on the load (watts) of the lights for the controller to 'turn on'.

Each brake light on the FJR consumes 21 watts at 12 volts. Two matrix of 9 LEDs/ea probably won't draw 0.125 watts. When Silent put a conventional bulb in parallel with the LED matrix he was adding load to the controller getting it to turn on and 'latch on' until turned off again. I would guess that his non-LED controller uses a FET to drive the output, FETs can behave like this.

Silent could purchase a 12 ohm/20W resistor and put it in parallel with the LEDs to fake out his controller and get it to work. The resistor will get DARN HOT, so placement would be important. This would give him the benefit of the extra, strobing brake lights but without the advantage of electrical power savings.

The first, best solution would be to use a modulator that is LED specific. Failing that, the only other choice would be to use a parallel load resistor, live with the wasted watts and very hot resistor.

 

[Silent]

Thanks ionbeam about summed it up perfectly.

I've opted to just go with the LED specific modulator, and move the non LED modulator over to my other bike. At least that way I'm not feeling like I'm wasting my money the actual brand of modulator is BackOff if anyone is interested.

Thanks guys

 

[ionbeam]

I guess I'll just go out and buy the LED stoplight modulator

NO YOU DON'T HAVE TO!!!!

Read my last post carefully. All you have to do is cut into the brakelight wire and "T" off the LED pos wires between the modulator and taillight.

I like the idea, but would I need a Stoplight Modulator to make this all work? I was just going to add LEDs for brake and separate LEDs for turn. I was originally thinking I could just splice into the power of the brake/turn lights and be ok? Or am I off my rocker?

If you are simply looking to add LEDs and don't want modulation you can directly tap the brake and turn signal wires, just be sure the LEDs you purchase have internal drop resistors or come with resistors.

If you want a modulator for the LEDs but want to keep the tail lights stock you can directly tap the brake wires to power the LEDs. Be sure the modulator is made for LEDs. The modulator would tee to the brake wire and the output would go to the LEDs.

If you want the tail lights to modulate you will have to cut the brake light wire and put the modulator in series between the brake switch and the brake light.

 

[ctfjr]

In a previous post Silent said that he was only running extra LEDs with the modulator, he didn't want the brake lights to flash, so cutting the brake light wire isn't an option.
Misc. electrical ramblings --

LEDs come in two types -- one with a built-in (internal) power dropping resistor and the other without, requiring you to install a resistor. Running LEDs that need an external resistor *without* the resistor will lead to dead LEDs PDQ because they need the resistor to reduce power. If Silent has had the LEDs on for any length of time and they still work it is a sure bet his LEDs contain an internal resistor.

Silent has said that his modulator specifically warns WILL NOT WORK WITH LEDs. There are many different electronic solutions to supply power to lights, many are dependent on the load (watts) of the lights for the controller to 'turn on'.

Each brake light on the FJR consumes 21 watts at 12 volts. Two matrix of 9 LEDs/ea probably won't draw 0.125 watts. When Silent put a conventional bulb in parallel with the LED matrix he was adding load to the controller getting it to turn on and 'latch on' until turned off again. I would guess that his non-LED controller uses a FET to drive the output, FETs can behave like this.

Silent could purchase a 12 ohm/20W resistor and put it in parallel with the LEDs to fake out his controller and get it to work. The resistor will get DARN HOT, so placement would be important. This would give him the benefit of the extra, strobing brake lights but without the advantage of electrical power savings.

The first, best solution would be to use a modulator that is LED specific. Failing that, the only other choice would be to use a parallel load resistor, live with the wasted watts and very hot resistor.

1st good answer Ionbeam! I would try a 25 ohm resister 1st (20W). It will probably work & only disappate 1/4 the wattage.

 

[ponyfool]

I did this on my Bandit years ago.

You are trying to mimic a brake light, right? What's the wattage of the bulb you are trying to mimic? Once you know that, are you required to mimic 2 bulbs, or just one? If only one, it's likely a 22 watt 1157 type brake light. If so, you will need to dissipate at least 22 watts minus the load of your LEDs to mimic the brake light and "fool" your device.

If that's what you are looking for, a 10ohm, 10watt resistor (if only mimicking a single brake light) should do the trick (that's what worked on my Bandit with the same device you have). However, it is a big resistor, and I must caution you, that SOB will get VERY HOT! So, mount it appropriately or else plastic will melt.

EDIT: Now I read the thread and see someone else posted basically the same thing.

 

[ionbeam]

I did this on my Bandit years ago...EDIT: Now I read the thread and see someone else posted basically the same thing.

Ready, shoot, aim? :lol:

 

[weekend rider]

Here is the best information that you will get. Take what you have and throw it away.

Now go and purchase what is made for what you are trying to do. Go to the HYPER LITES web sight and look at everything they have. They have what you want to do

When you get done messing around with your truck stuff you will have spent twice the money and nothing is standard and when it brakes down on the road it can get you pissed off and all you want to do is sell the bike because of those lites.

when you get done it will be a cluster f%%%%k