I need help wiring up a dual headlight mod ....

[cyclin-scott]

OK, here's one for you electrical engineering types ....

I'm getting ready to do a dual headlight mod, with a Buell XB headlight, on my 98' GSe. What I want to do is have the headlight wired up so that on the low beam, only one light is operating. Then when the brights are on, I want both to be on. Obviously, giving me more light.

If there's anyone that might be able to shed some light on this, please let me know. Also, I'm a "picture" kind-of a guy, so if it would be possible to post a diagram of said solutions, I'd really appreciate that too.

Thanks in advance ... Scott

[starwalt]

I know the Buell lights have been added to the GS before, but you most certainly will learn about some wiring if you get this going.

Essentially all you have to do is use the "low" wire of the GS to run the single lamp, and the "high" wire to light the second. This should keep your control switch like the GS and require no fiddling there.

Basically you need to identify which wire does what and then cut the old lamp connector and splice accordingly into the Buell wiring.

On the GS connector, the white wire is the low beam, the yellow wire is the high beam. The black\white wire is the common and goes to ground (negative battery connection).

Do you have the Buell lamp wiring or just the lamps and housing?

[joedude]

Having both headlights on while in Hi-beam is a good idea, but the only problem with that is possibly requiring more voltage from your wiring harness than it's capable of delivering and burning it out. A solution would be to beef it up, but then you could be requiring more from your battery/stator than it can deliver and having to recharge your battery lots and possibly inflicting more wear on your stator than necessary (I'm not sure if you could damage your stator by doing this... maybe it'll just not provide enough power).

Now if everything works fine, and you run both lights, you might still not be delivering adequate power to your lights to illuminate the road up front to your bulb's full potential.

Personally I like the idea, and I've been thinking about it aswell, but if I do it, I think I'll have an auxiliary light of lower wattage working as a fog light illuminating in a wide angle. I want to use a low wattage bulb so that my hi-beam can still use most of the power and throw a single stronger beam of light rather than two somewhat strong beams.

Just my thoughts

Basically, check wattage, monitor draw and battery condition regularly.

Good luck and post pictures!

[cyclin-scott]

I know the Buell lights have been added to the GS before, but you most certainly will learn about some wiring if you get this going.

Essentially all you have to do is use the "low" wire of the GS to run the single lamp, and the "high" wire to light the second. This should keep your control switch like the GS and require no fiddling there.

Basically you need to identify which wire does what and then cut the old lamp connector and splice accordingly into the Buell wiring.

On the GS connector, the white wire is the low beam, the yellow wire is the high beam. The black\white wire is the common and goes to ground (negative battery connection).

Do you have the Buell lamp wiring or just the lamps and housing?

I don't have my lights yet ... I just wanted to get a jump on the idea. 

Thanks guys for bringing up the thought about trying to draw too much power ... I didn't think about that before. Does anyone know if the Buell headlights use the same H4 bulb that we do? (I have a feeling like I just asked a very retarded question, but what the hell ...)

Is there someone on here that might have more of an educated (ie you know electrical/ wiring stuff) opinion about this? (Don't mean to be any offense to those that have already posted ... thanks again, btw.)

[NiceGuysFinishLast]

Geep would be good to ask, or starwalt, or scratch.. they're all pretty smart guys, you may PM them a quick question. Geep has forgotten more on any engineering subject than I will ever know in my lifetime. 

[cyclin-scott]

Geep would be good to ask, or starwalt, or scratch.. they're all pretty smart guys, you may PM them a quick question. Geep has forgotten more on any engineering subject than I will ever know in my lifetime. 

Sweet, thanks for the user-names! 

[cyclin-scott]

In searching, I found this wiring description from "John Bates" from about a year ago. It seems pretty solid, but was wondering/ wanting more information about wiring in the diode. Where would I find/ get one? And are diodes hard to wire in o the circuit?

Anyone ... ?

[cyclin-scott]

Damn-it. I hate when I post w/o pasting the thread....

Here goes :

Connect the low beam wire from the switch to the right headlight.
Connect the high beam wire from the switch to the left headlight.
Connect a diode between the low beam wire and high beam wire.
The cathode end (usually marked by a stripe or band)  of the diode should be connected to the low beam wire.
The diode should be capable of carrying greater than 5 amps continuosly.
The other terminal of each headlight should be connected to ground.

On low beam the right headlight will light.
On high beam both headllights will light. 

[joedude]

Diodes are real easy to work with. Here's a simple photo to show how to wire them:

Current flows from the positive side (+) to the negative or ground (-)

diodes allow current to flow in one direction but not in the other... so in the way described above, when the low beams are on the current would not be allowed to bridge thru to the high beam bulb because of the electrical 'wall' that is created by the diode... otherwise in high beam mode, the diode will allow current to flow thru it and illuminate the other bulb so that both are on at the same time.

I figure you can pick diodes up at Radio Shack (I work at an airline... so I just get them from the Avionics parts department... they have all kinds of nifty and usually expensive long lasting stuff there!). Make sure to get one that is rated for 5 Amps continuous (ask the guy at the counter and he'll help you out), and wire it up. Make sure to test it out before you solder everything, just to make sure that you have proper orientation of the diode.

Hope this helps

[cyclin-scott]

Diodes are real easy to work with. Here's a simple photo to show how to wire them:

Current flows from the positive side (+) to the negative or ground (-)

diodes allow current to flow in one direction but not in the other... so in the way described above, when the low beams are on the current would not be allowed to bridge thru to the high beam bulb because of the electrical 'wall' that is created by the diode... otherwise in high beam mode, the diode will allow current to flow thru it and illuminate the other bulb so that both are on at the same time.

I figure you can pick diodes up at Radio Shack (I work at an airline... so I just get them from the Avionics parts department... they have all kinds of nifty and usually expensive long lasting stuff there!). Make sure to get one that is rated for 5 Amps continuous (ask the guy at the counter and he'll help you out), and wire it up. Make sure to test it out before you solder everything, just to make sure that you have proper orientation of the diode.

Hope this helps

Hey, thanks Joe ... as posted earlier in the thread, do you think that with the diode in place, w/ the brights on, that I might still run into the problem of not getting enough power to light up the bulbs to their full potential? If so, what do I do about it?

Thanks again,

[joedude]

Well, you're still drawing the same amount of power from your electrical system.

You may want to look into getting some real good bulbs, Like the Sylvania ones, that would give excellent output at a lower wattage... that would allow you to get more light with less power draw by running a more efficient bulb.

check this thread out

[starwalt]

John Bates' idea is really good and will get you both lights. I didn't think about a duel illumination scheme.

BEWARE: Just to reaffirm joedude's post you must use a diode capable of handling the continuous current. If you pick a 1A diode, it will overheat and pop/burn up.

I just took apart a spare light switch here and have confirmed that the GS switch does not turn both on when on "High". I didn't think it did, but now have confirmed it.

[LimaXray]

ok ok wait a second.  I'm a computer/electrical engineer, I think I can help!.  I don't know if a diode like this will be a good idea.  There is a voltage drop across a diode so the low beam will see <12v and possibly be dimmer when the high beam is on.  That extra power lost from making light will now be used to make heat in the diode.  Give it a try and see if it works, I can't hurt anything.  It may be hard to find a diode capable of handling that much current, so what you can do instead is use multiple diodes with a lower rating in parallel(side by side).   

A better option would be to use the same diode idea, but instead use it to drive 2 relays instead of the 2 headlights.  Each relay would then power each light.  Run a single power line from the battery to the relays with a fuse. 

Find out the wattage of the bulbs and I will tell you what diode(s) to use or what gauge wire and what fuse to use.

In either case, I don't think there will be a problem with drawing more power then the bike can produce, the only potential, yet unlikely, problem would be drawing too much current through the headlight wires.  Although I only think this will be a problem if you were to get HID lights instead of the halogens.  This of course is avoided by using the relay method.

[John Bates]

.................... There is a voltage drop across a diode so the low beam will see <12v and possibly be dimmer when the high beam is on.  .............................

Yes, there is about .7 volt drop across a diode so some power will be lost.

A better option would be to use the same diode idea, but instead use it to drive 2 relays instead of the 2 headlights.  Each relay would then power each light.  Run a single power line from the battery to the relays with a fuse. 
.....................................

This would be a better solution, however more complex to implement.

I think Buell uses 55 watt H3 bulbs for both hi and low.  If I'm right then with both turned on you would have 110 watts load, about 50 watts more than the standard GS load (60 watts on high).

[LimaXray]

Yes, there is about .7 volt drop across a diode so some power will be lost.

.7 is probably about average, but not all diodes are the same.  I'm not sure how important this is as idk at what point the one light will be noticably dimmer than the other.

I took a quick look on Digikey, and thought this may be a good fit:
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=119569&Row=599327&Site=US
It will take a forward current of 5A (which should be fine as worst case is 55w/12v= ~4.6A).  The forward voltage drop is 0.55v, which is probably as low as you're gonna get.  Also the reverse breakdown voltage is 30v (this is important because there is a point where diodes do 'turn on' in the opposite direction).

Now for the wires, you'll need at least a 16awg wire to drive both of those lights.  That means if you do the diode method the high beam wire should be at least 16awg.  If you do the relay method, I'd use 14awg to be safe along with a 10 amp fuse (110w/12v = ~9.2A). 

[Chuck]

What's all this diode crap?!?

If you're in the United States, I believe your headlights must be on whenever the vehicle is operating.

So, go to your wiring harness, and splice into an on-with-key wire.  (There are several.)  Hook that up to your low beam bulb.

Then get your high beam current from the Lo/Hi switch.  Hook that up to your high beam bulb.

There.  Done.  Come on, people, you don't need an EE degree for this!

[LimaXray]

Sounds like someone has an electronics phobia 

If the high beam wire is at least a 16 awg wire, a diode would still be the easiest way to do it.  There's no need to modify anything and it would be totally reversible.

Tapping into a switched wire is not a bad idea, but you do have to be extra careful about which wire you tap into as you are putting a permanent 5A load on a line that wasn't designed to be there. 

I still think the right and proper way to do it would be to run a separate line to the battery and use a relay.

[Chuck]

K.I.S.S.

[starwalt]

K.I.S.S.

My original post is KISS. The stock GS switch is either LOW or HIGH. There is no OFF.

So if our friend does what I mentioned previously with the orignal headlight wiring/socket he will have a bulb on with the bike on and the other when switching to HIGH.

He just needs to hook up it up properly.

[LimaXray]

Yeah the diode way is the easiest by far