LED Brake Lights on a Gen II (Some questions)

[jblanken64]

So I have the LED bulbs and, as expected, they need resistors to not interfere with the ABS. I picked up some harnesses that add some resistors inline with the existing 1157 socket. The link is below:

https://www.amazon.com/gp/product/B072JQQQLV/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

The harness work great. I hate splicing into wires if I don't have to. The thing I'm worried about is the heat dissipation of the resistors. Using an IR thermometer, I measured temps over 180 degrees just from the taillight. So the questions:

1) For those that have done this (or tried), what did you do about the heat buildup?

2) Where did you mount the resistors? I'm looking at the frame around the access point to the lights, as it is a metal frame.

There doesn't appear to be a way to introduce any airflow to the resistors and with summer approaching, the heat issues would probably just be compounded. I'd hate to not use these bulbs, as they are very nice.

 

[Ianstein]

You could try mounting the resistors to a larger heat sink like one of these.

https://www.ledsupply.com/led-heatsinks/half-brick-heatsink-black-powder-coated-finish-with-mounting-holes

A dedicated aluminum heatsink should dissipate heat better than mounting them to the frame.

 

[mcatrophy]

Resistors must be bolted to a metal heat sink, this must allow for airflow. Take into consideration that when you are stationary with the brake applied, there will be a lot of heat to get rid of, and no natural airflow to take the heat away. Depends on how long the wires to the resisters are.

 

[jblanken64]

Resistors must be bolted to a metal heat sink, this must allow for airflow. Take into consideration that when you are stationary with the brake applied, there will be a lot of heat to get rid of, and no natural airflow to take the heat away. Depends on how long the wires to the resisters are.

I've thought about this. I can modify the harness to use longer wires and route those to a location that has airflow. I'll also need to be mindful of water intrusion, as most places that can get airflow can also get water flow. I have a number of old CPU heatsinks laying around that should do the trick. I was also thinking that these resistors seem like overkill. I'd be surprised if the regular bulbs generate this much heat. That's an easy thing to test.

 

[RossKean]

Hate to say it but this seems (to me) like a bad idea. I assume that the use of LED is purely for increased brightness? Definitely no power saving with the load resistors and the potential of a melt-down would make me nervous.. I wonder if there is any other practical way to spoof the system to eliminate errors. I also wonder if a lower resistance solution might be possible to reduce current draw (and heat).

For my money, I would keep the stock brake light and turn signal system and add an aftermarket attention getter like Hyper-Lites.

 

[jblanken64]

Hate to say it but this seems (to me) like a bad idea. I assume that the use of LED is purely for increased brightness? Definitely no power saving with the load resistors and the potential of a melt-down would make me nervous.. I wonder if there is any other practical way to spoof the system to eliminate errors. I also wonder if a lower resistance solution might be possible to reduce current draw (and heat).
For my money, I would keep the stock brake light and turn signal system and add an aftermarket attention getter like Hyper-Lites.

Turn signals were easy. Replace the relay and plug in the new bulbs. Problem solved.

The LED Brake lights can probably get by with less resistance. I probably just need to measure the resistance across the standard bulb and make sure I do about the same.

As far as additional lighting, I already have the light kit installed in my Givi top case (doesn't help if I'm riding without it) and a Whelen LIN3 mounted below the license plate with a flashing modulator.

The LED brake lights are more of a "I think they look nice, they're really bright, and I want them" type of thing. Just gotta solve that heat issue.

 

[mcatrophy]

...The LED Brake lights can probably get by with less resistance. I probably just need to measure the resistance across the standard bulb and make sure I do about the same.

...

Measuring the standard bulb's resistance will give a much lower reading than their hot resistance, something like a factor of 5. Hot resistance will be around 12x12/21, 7 ohms (or maybe 14x14/21, 9 ohms).

While it's the cold resistance that the computer senses, you probably can get away with significantly higher (remember, the higher the resistance, the less power is dissipated).

If it was me, I'd buy a range of resistors, find the highest value that doesn't upset the ships computer, then use a value around 2/3 of that.

Also, you don't need a resistor for each bulb, one will do.

 

[rbentnail]

Drill a little hole in your airbox, from the center of the bike out to the left; insert resistors so they're in the middle of your air filter; seal hole with silicone. Or simply mount your heat sink near the air intake entrance.

Always have air flow, always dry. Problem solved, send beer. PM for address.

 

[SkipS]

I put my heat sink here. 1000 miles no issues https://s31.postimg.cc/7jg6kr2yj/20180326_162906.jpg