LED lighting question

[cactusjack]

I'm still trying to work the last remaining kink out of my trailer wiring. I added a 15" LED STT light assembly to the back of the cargo box. My intent was to utilize it as a tail/center stop light. In order to do this, since there is no separate stop light circuit in a 4-wire trailer system, I installed a Stoplogic third brake light module.

The concept is very simple: you connect the LT and RT inputs to the module and when it detects 12v on both inputs (when the brake circuit is actuated), it opens a gate and supplies 12 to the output side, which connects to the stop light.

It works great when the trailer is connected to my truck. However, when the trailer is connected to my Nomad, the Stoplogic module does not prevent the turn signals from actuating the center stop light, so in a left turn situation the left turn signal and the center stop light flash, vice-versa in a right turn situation. The center brake light does work properly, though.

My best guess is that it has something to do with the lack of incandescent lights on the trailer. They are all LEDs, except for the little interior courtesy light and the license plate light. The resistance through the LEDs is probably not enough to properly trigger the gates inside the Stoplogic module.

I should add that when connected to the Nomad, there is a Hoppy 46255 power taillight converter which isolates the trailer lighting from the motorcycle. The motorcycle brake, tail, LT and RT circuits are merely triggers to activate the relays in the Hoppy converter, so the trailer doesn't benefit from the resistance in the bike circuits.

Anybody have any thoughts on how to make this work? If I can't fix this, my only alternative is to either let the center light flash with the turn signal, or disconnect the stop light input and use the center light as a running/tail light only.

[VulcanE]

CJ, unlike a car, our motorcycles have separate circuits for the turns and brake lights, thus the Stoplogic module will only receive an input from either the left or right turn signal, but not both when you have a signal on and apply the brake. you might could try wiring the center light on the trailer to a circuit from the Nomad tail light?????

[ringadingh]

Im not very familiar with your setup, but would guess that either your Stoplogic unit or the Hoppy converter can't sense enough of a load to activate. Try to test it by substituting incandescent bulbs temporarily and see if it starts to work properly. If it does, you have to increase the resistance of the LED's

[cactusjack]

Originally Posted by VulcanE

CJ, unlike a car, our motorcycles have separate circuits for the turns and brake lights, thus the Stoplogic module will only receive an input from either the left or right turn signal, but not both when you have a signal on and apply the brake. you might could try wiring the center light on the trailer to a circuit from the Nomad tail light?????

I understand. the Stoplogic module is designed specifically for the application I am using it for. It takes the LT and RT signals as inputs and when they are both energized, which is only when the brakes are applied, it sends 12v to the output side, which powers the stop light. That part all works fine. It's when the left or right turn signal is on that it isn't working as designed. It isn't supposed to flash.

[cactusjack]

Originally Posted by Ringadingh

Im not very familiar with your setup, but would guess that either your Stoplogic unit or the Hoppy converter can't sense enough of a load to activate. Try to test it by substituting incandescent bulbs temporarily and see if it starts to work properly. If it does, you have to increase the resistance of the LED's

How would one go about increasing the resistance in the LED's? Add inline resistors?

[rhunt4]

be sure your ground is connected to the batery then to the box then to the trailer lights not fram grounded. motorcycle have a lot of trailer problems with lights due to hard grounding problems.

[Yellow Jacket]

Originally Posted by cactusjack

How would one go about increasing the resistance in the LED's? Add inline resistors?

I believe that folks are talking about the issue that arises when incandesent lights are replaced with LED lights and they don't flash properly. As I understand it, the LED lights don't draw as much current as an incandesent. Most flashers are activated by the amount of current flowing through the circuit.

When the voltage applied remains constant the resistance and current flow act in opposites to each other. High resistance produces low current flow and low resistance produces high current.

The "load adapters" that you see being recommended when replacing incandescent lights with LED lights acutually decrease the resistance of the circuit.

I don't think this is what is causing your problem.

In your post you stated this about the Stoplogic module:

The concept is very simple: you connect the LT and RT inputs to the module and when it detects 12v on both inputs (when the brake circuit is actuated), it opens a gate and supplies 12 to the output side, which connects to the stop light.

OK, according to that, the center stop light will only be on when 12v is applied to both the LT and the RT inputs.

1. When the brake is on and neither turn signal is blinking the center stop light will be on.

2. When the brake is off and either turn signal is blinking the center stop light will be off.

3. When the brake is on and either turn signal is blinking the center stop light will only be on while the turn signal is on since that will be the only time that both inputs are on. Therefore the center stop light will flash with the turn signal.

I'm sorry that this is getting long winded but bear with me.

I don't think adding a load adapter or trying to change the resistance of the LED's will solve your problem. I think that the Stoplogic module may not be capable of doing what you want it to do while connected to the Hoppy.

I know that this doesn't give you a solution to your problem. I am going to ponder on this situation and see if I can come up with something that may actually help.

[Yellow Jacket]

I sent you a PM with a possible solution! Keeping my fingers crossed. :)

[cactusjack]

Thanks for the advice, folks!

Alas, I am at work now and can't tinker with it until this evening. I did run a continuous ground from the bike (-) terminal through the Hoppy and to every device on the trailer. I know how flaky chassis ground is on a trailer. I've fought ground issues in the past on my boat trailer.

It may just be that this ain't gonna work. I'm not ready to throw in the towel just yet.

If anybody has more ideas, I'd like to hear them!

[ringadingh]

Did you substite icandescent bulbs in place of the LED's just to check the circuit load.?

[cactusjack]

No, it really isn't that easy to do. For now, I just disconnected the third brake light circuit. I'll revisit the challenge at some point in the future.

[VulcanE]

Good luck with it Scott

[cactusjack]

I contacted American Technology Components, the manufacturer of the Stoplogic controller, about this issue. Their reply was that the Stoplogic third brake light controller is designed to work with incandescent brake lights. Apparently, they rely on the ground through the incandescent filament. LEDs do not have this same ground path. It would probably work fine if the trailer wasn't electrically isolated from the bike by using the Hoppy taillight converter, in which case the filaments of the Nomad's incandescent lights would serve as a path to ground.

So, I guess if I really want to use that third brake light, I am going to have to run a separate brake circuit from the bike to the third stop light at the rear of the trailer. I may do this, but probably not for awhile.