Attention, "L" owners...

[Steve]

Do you like the look of your tail light, but wish it was brighter? :shock:

I am working on a prototype for an LED board to replace the stock bulb. I was following my wife's 850L through the mountains of West Virginia over the Labor Day weekend, and realized that I had a difficult time seeing the tail light in daylight. Brake lights were not much of a problem, and night-time use was not bad, but I want something better.

A search of what is available shows that there is NOTHING specific for our GS Ls. The concept is out there, but the market focuses on Harleys and Metric Cruisers. Here is one example of a generic Harley light. Note that it is $125. We might be able to adapt something generic, but so far, my requests for specifics regarding sizes of the boards have gone unanswered, and I am not going to buy one of each, just so I can measure them.

Scroll down to the third light on this page to see a more-specific light for Harleys. Note that this light is only $166.
This is the one that inspired me.

I have designed two lights for our L models (because that's all I have here to work with), one with G S in the light (similar to the H D above), the other one is solid. Each one has over 100 LEDs, including some that shine out the side and white ones to illuminate the license plate. Depending on how many boards I order at a time, I think I can make these available for an introductory price of $75 for the solid version and $80 for the G S model. They will fit in the stock light with no permanent modifications, and you can go back to a stock light if you should ever wish to.

Is anybody besides me interested in something like this? 8-[

If there is considerable interest in another model that shares a tail light with several others, I can work one up for that, too, but I will need a loaner tail light assembly to do the engineering.


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[MissFabulous]

For what it's worth, as in, if it gets your creative juices further flowing, when I first started riding, a good friend of mine ended up (completely coincidentally) behind me for a long stretch on my 1980 550E. The PO installed a
a rotating LED light bulb in my tail light. My buddy behind me said it's really noticeable because the light rotates (goes steady when I stop) but he felt it could be brighter. We discussed possibilities of rigging two lights to work simultaneously in the housing as there is plenty of room in there. Not sure what the tail light housing is like on an L, but looks like some of them aren't tiny either. Anyone know if it would require any upgrades to handle powering another bulb? The LED doesn't use as much power as the old style bulbs, but not sure how combining a few power drains would affect performance.

Where there is a will, there is a way!

[Steve]

The problem with most of the "rotating" bulbs is that, while they use about a dozen LEDs, they acheive the "rotating" effect by only lighting 2 or 3 at a time, going around a circle. That means that you only have 3 LEDs on at any given time. The diameter of the circle (the bulb) is only about an inch, so you really have to look carefully to see it. Since LEDs are rather directional, they don't tend to light up much of the stock lens. The stock lens is designed to capture light coming from the bulb itself and from the reflector, which re-directs light that has come off the side of the bulb.

There are bulbs that have LEDs pointing sideways into the reflector, but that is still a compromise. Besides, when you use those bulbs, you lose the white light for the license plate. I don't know how officers feel about a colored light for the license, but around here, they will write you a ticket for having NO light.

My design will FILL the tail light with LEDs, so there will be no mistake that the light is ON.
The brake light will be similarly unmistakable. :shock:

Here are a couple of pictures of the L tail light:
(This is just showing the shape of the light. I will get pictures of stock bulb and LED comparison soon)




Here is a crude, quick PhotoShop approximation of what the GS light would look like:
This is the tail light setting. For brake lights, these LEDs get brighter, and the rest of the light fills up at the brighter level.


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[txironhead]

I'm thinking about doing a total remake of my tail section with a frenched LED board, and I was wondering a few technical things:

First, are you using a resistor to change the brightness between tail and brake lighting? Also, what is the brightness rating (CP) of the LED's you're using? With 100 LEDs, how are you wiring them to utilize the 12v system, and is an "overload" circuit required?

Not sure how I'll end up doing it, but I got my inspiration from another thread here. Also trying to figure out a side marker setup that will be as low-profile as possible while being visible from the rear and side.

If I had a spare tail section for my E, I'd send you one so you could come up with a design for it. If I do the mods I'm thinking of, I won't need the stock taillight and I might send it to you then.

[mortation]

I used a tombstone tail light like the one CRC2 sells. Cheaper on eBay bright as hell and looks sweet I'll try and get my pics back online tonight

[Steve]

... are you using a resistor to change the brightness between tail and brake lighting?

Yes, resistors and diodes for the two brightness settings.

... what is the brightness rating (CP) of the LED's you're using?

I have not yet decided on the final LEDs. I got some 6000 mcd units to do some initial testing, but will probably use 8,000 or 12,000 mcd in the final product. If they don't work, I have some 25,000 mcd units available. :shock:

... how are you wiring them to utilize the 12v system, ...

Not sure exactly what you are asking, but be assured that it will be done in an electrically sound manner.


[quote=txironhead;697834]... and is an "overload" circuit required?/quote]
You mean 'overload' like 'fuse'? No fuse necessary. 'Overload' as in 'what happens if my r/r fries'? Again, no problem.

If I had a spare tail section for my E, I'd send you one so you could come up with a design for it. If I do the mods I'm thinking of, I won't need the stock taillight and I might send it to you then.

Thanks. It won't be permanent, I only need it for measurements and mounting options, then you can have it back.


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[txironhead]

Well, most of the LEDs I've seen range from .5 volt to 2-4 volts each. Just wondering if you were soldering them all straight to a bus board and letting the regulators and diodes do the work or if there was a "four bus of 25 LEDs each" type setup.

[Regent]

I'd be interested in picking one of these up this winter!

[Steve]

When I have them ready, it won't have to wait for a "major" winter project. :shock:

Probably 5 minutes, tops, as long as you know which end of a screwdrive to pound on. 8-[


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[txironhead]

Well, I decided not to make a custom taillight for the "E". Actually, my wallet decided it. I'm still working on the bodywork, and I just got done reassembling the taillight, painted the "chrome" trim black, just the outer ring that fits between the lens and the tail section. It's actually part of the reflector, so it required some fancy masking. (The "ring" had rubbed off to that ugly yellow plastic).

If you'd like, I can send it to you so you can take measurements. I would need it back pretty soon, like a week or two. Any chance of getting one of the prototypes?

From what I understand, the taillight is the same on the 80-81 GS750E and GS1100E, but it might fit others.

[Steve]

If you'd like, I can send it to you so you can take measurements. I would need it back pretty soon, like a week or two. Any chance of getting one of the prototypes?

From what I understand, the taillight is the same on the 80-81 GS750E and GS1100E, but it might fit others.

Send it when you can, I'll PM you my address. It will take just a bit for the measurement process. Would like to keep shipping weight down, but I will need the entire light assembly and lens.

Yes, no problem getting you one of the prototypes.
I can even knock a little off the price for your offering your light for measurement. \\/


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