Alternator Dilemma...(RESOLVED)

[vexlak]

Dilemma…
While riding around the town (NYC) the battery charge light came on. Remained constant no matter what. So I suspected the alternator gave up. I took off the tank and measured the charge 12volts. Sure enough it looks as the alternator is gone. Here is the good part. When I took off the double blue wire connected to the alternator (I assumed that one goes to the charge light the other is my dilemma) and charged the alternator with a positive current (from the battery) where I got the blue wires off, VOILA the alternator was charging close 14volt to the battery. In other words the alternator gets signal from somewhere to start charging. Is my alternator gone or am I missing something. BTW the light never came off no matter what I did. Also, where can I get a wiring diagram for my bike? Any suggestion will be appreciated.
Thank you!!!

[deilenberger]

My suggestion is - see a dealer. You stand a chance of doing some very expensive damage by sort of randomly connecting wires to the battery.

There is usually an internal voltage regulator in the alternator.. if your charge light is on - the voltage at the regulator is less than at the battery (bad condition.)

Without a wiring diagram I wouldn't even dream of connecting up wires, and my background is EE/physics.. Since I suspect your bike is under warranty, and there is a BMW dealer (company store in fact) on 11th Ave in NYC, that's my suggestion. Take the bike to them.

[vexlak]

THX for your response.
My bike is no under warranty. I posted the tread under r1200 by mistake. My baby is ’02 r1150r with 18K miles. I posted the same tread on the 1550 board. Sorry for the confusion. Any idea where I can get the wiring diagram?

[deilenberger]

THX for your response.
My bike is no under warranty. I posted the tread under r1200 by mistake. My baby is ’02 r1150r with 18K miles. I posted the same tread on the 1550 board. Sorry for the confusion. Any idea where I can get the wiring diagram?

Haynes manual has them. I just looked - one blue wire goes to the light, the other to the diagnostics plug. Dunno exactly what you're doing by connecting it to the battery, but it's nothing that's supposed to happen. You may want to check Fuse-1..

[vexlak]

THX for your response.
My bike is no under warranty. I posted the tread under r1200 by mistake. My baby is ’02 r1150r with 18K miles. I posted the same tread on the 1550 board. Sorry for the confusion. Any idea where I can get the wiring diagram?

Haynes manual has them. I just looked - one blue wire goes to the light, the other to the diagnostics plug. Dunno exactly what you're doing by connecting it to the battery, but it's nothing that's supposed to happen. You may want to check Fuse-1..

Diagnostic plug? Is that the where you plug the computer?
Can you PLEASE scan the diagram and either email or PM it to me? I will buy the manual later however it will take few days and the bike is in desperate need of repair now. Also why fuse No.1? All of my instruments are working as they suppose to. Also I checked the fuse and it looked just fine.
Thank you in advance!

[deilenberger]

THX for your response.
My bike is no under warranty. I posted the tread under r1200 by mistake. My baby is ’02 r1150r with 18K miles. I posted the same tread on the 1550 board. Sorry for the confusion. Any idea where I can get the wiring diagram?

Haynes manual has them. I just looked - one blue wire goes to the light, the other to the diagnostics plug. Dunno exactly what you're doing by connecting it to the battery, but it's nothing that's supposed to happen. You may want to check Fuse-1..

Diagnostic plug? Is that the where you plug the computer?
Can you PLEASE scan the diagram and either email or PM it to me? I will buy the manual later however it will take few days and the bike is in desperate need of repair now. Also why fuse No.1? All of my instruments are working as they suppose to. Also I checked the fuse and it looked just fine.
Thank you in advance!

Yes, and sorry I don't have a scanner. I suggested fuse one since it's the power feed for the alternator (which needs power to make power.)

[Arbee]

Dilemma…
So I suspected the alternator gave up. (Maybe)
(There are 3 parts to this alternator regulator and battery)

Sure enough it looks as the alternator is gone.
(not until you check & polish battery terminals)

In other words the alternator gets signal from somewhere to start charging.
(from the regulator, the alternator is charging all the time except the regulator blocks it)

Is my alternator gone or am I missing something.
Your alternator is unlikely to be gone, however the brushes may be worn or the regulator diode is cactus
or your battery terminals are loose corroded or oxidised (lead does that)

cheers arbee
I have a circuit but not for the R1150R.

[riceburner]

Dilemma…
While riding around the town (NYC) the battery charge light came on. Remained constant no matter what. So I suspected the alternator gave up. I took off the tank and measured the charge 12volts. Sure enough it looks as the alternator is gone. Here is the good part. When I took off the double blue wire connected to the alternator (I assumed that one goes to the charge light the other is my dilemma) and charged the alternator with a positive current (from the battery) where I got the blue wires off, VOILA the alternator was charging close 14volt to the battery. In other words the alternator gets signal from somewhere to start charging. Is my alternator gone or am I missing something. BTW the light never came off no matter what I did. Also, where can I get a wiring diagram for my bike? Any suggestion will be appreciated.
Thank you!!!

Vexlak - could be a loose/worn alternator belt?

[FloridaBeakster]

Here is a schematic for an 1150GS, the charging circuit should be the same:

(this links to a PDF)

R1150GS Wiring Schematic PDF

[vexlak]

Thank you all for your suggestions and the diagram.

Here are few answers:

Sure enough it looks as the alternator is gone.
(not until you check & polish battery terminals)

I have new battery and tight shiny copper connection

My belt is almost new and tight as it should be.

Is the regulator diode part of the alternator? Since there are no other wires I am assuming that it is. I believe that it could be repaired by an alternator shop. New alternator is around $350...

Any comments?

[boxermania]

vexlak

Here is the wiring diagram for your bike, it can be enlarged by clicking on the lower right hand corner.

http://r1150r.smugmug.com/photos/15908153-O.jpg

The alternator has two wires, the one coming to the B+ which ties back to the starter motor solenoid and the one form D+ that supplies the idiot light.

I would check all the connections to see that they are tight, before you spring for a new alternator, have it checked at one of the auto parts stores. There is also this outfit, where you might be able to get an alternator for less money, that is if you need it.

http://www.beemerboneyard.com/

Good luck.......and keep us posted.

[vexlak]

Thank you boxermania.

The diagram is great however the alternator has three wires coming of off it. One main which goes to the starter as it shows on the picture. There is also a connector with two blue wires. One goes to the idiot light the other to the ??? The '00 GS diagram shows that it goes to the diagnostic plug...
I think that the regulator on the alternator may be shot or I may have a ground on the wire. I will inspect the wires and see if they have a problem If not, then I have to take out the alternator and bring it to a alternator shop to see if they can fix the regulator. Will keep you posted.
Thank you again!

[boxermania]

vexlak

Forgot another bit of info......yes, the alternator has the voltage regulator built in. The regulation is done by an array of diodes. To verify the alternator operation, measure the voltage from B+ to ground with the engo\ine at 3,000 rpm, if irt is around 14 volts tou are OK, if it is the same as the battery voltage when the engine is off, the alternator is the problem.

Like I suggested before, if it gets to that, have it checked and check around for pricing. Chicago BMW discounts parts 20%.

[daslimpet]

Hey Vex,
I once had an identical situation with my 02R. You might have a look at the electrolyte levels in the cells of your battery. Mine had boiled off to the point where the battery would not take a charge properly from the alternator. After topping off the levels and reconnecting everything the lbattery warning light was off and stayed off.

As a side benefit to the remedied battery, my signal minder flasher unit with gremlins like stuck on turn lights and unresponsive switches also behaved perfectly, and my idle improved. A healthy battery makes a difference with thease uber-beasts, as it turns out.

I've since replaced the battery, but keeping on top of the electrolyte levels got me another two years of service. May you have the same fortune.

Best,
Mike in MN

[vexlak]

Hey Vex,
I once had an identical situation with my 02R. You might have a look at the electrolyte levels in the cells of your battery. Mine had boiled off to the point where the battery would not take a charge properly from the alternator. After topping off the levels and reconnecting everything the lbattery warning light was off and stayed off.

As a side benefit to the remedied battery, my signal minder flasher unit with gremlins like stuck on turn lights and unresponsive switches also behaved perfectly, and my idle improved. A healthy battery makes a difference with thease uber-beasts, as it turns out.

I've since replaced the battery, but keeping on top of the electrolyte levels got me another two years of service. May you have the same fortune.

Best,
Mike in MN

Tnx for your suggestion.
I have a brand new (six month old) Odyssey battery. It is a dry battery. In addition I measured the charge (please read above) and it showed no juice coming for the alternator until I send it a positive signal.

[MattPie]

When I took off the double blue wire connected to the alternator (I assumed that one goes to the charge light the other is my dilemma) and charged the alternator with a positive current (from the battery) where I got the blue wires off, VOILA the alternator was charging close 14volt to the battery. In other words the alternator gets signal from somewhere to start charging. Is my alternator gone or am I missing something. BTW the light never came off no matter what I did. Also, where can I get a wiring diagram for my bike? Any suggestion will be appreciated.
Thank you!!!

I have no particular expertise, but I think you're right base on some obervations of my own. When I start my bike (2004), it seems like maybe 10 seconds after starting, something kicks in. The lights may dim just a little, and the idle RPM drops off. I assume it's the battery charging circuit activating. When I had a fairly dead battery earlier this year, the bike would start and run for those 10 seconds, but when the (presumed) charging circuit kicked in the bike would stall (either from the load or the supply voltage dropping too low). I'd think that it was done this way for cold starts and whatnot when the bike couldn't support running and charging the battery immediately, or it could be an effort to keep the engine load light while the oil pressure stabilizes. Typical German over-engineering.

I fear the signal may come from the computer. If charging works without the wire connected you may be able to get away with it, but that wire may also turn the charging circuit on and off to protect the battery.

[vexlak]

First and foremost:
TNX to all of you bimmer riders helping out and commenting. This could not be done without you.
Enough of *&^%$$.
Here is what I found. After looking on your experience and speaking to a great guy at http://www.beemerboneyard.com (thank you boxermania), I found a shorted wire under the cluster board. Someone before me (I got the bike used) must have taken the cluster panel off and in process of putting it back, pinched the blue wire supplying the idiot charge light. It was fine for three years and all of the sudden it gave up. This caused the wire to catch ground hence not sending the power signal to the alternator that it is time to start to charge. One problem fixed relatively cheap.
I still am planning to replace the clutch and check the spline. See how that goes.
TNX again!

[CycleRob]

Very savvy diagnostic on your part! The charge lite going full on with no alternator output at first told me the regulator died (or was murdered). Second possibility is the (blue) wire from the bulb to the alternator grounding out. In both cases the charge lite goes bright and the alternator does nothing but spin.

It's strange, but this type of alternator activation has been around since the mid 70's GM cars. The key-on power goes thru the charge bulb TO the alternator's built in solid state regulator, turning on the charge circuit. The bulb burns out, your alternator charges zero.

****** On our bike, if you turn the key on and there's NO red charge lite on, the bulb is toast and your alternator won't have ANY output. The solution, if you're on a trip far away from home, is to replace it with one pirated from the signal indicators. The tools in the toolkit allow you to remove the 3 big Torx caps retaining the big chrome gauge housing for bulb socket access.******

[sweatmark]

I like how we're starting to do some real wrenching and problem solving here in R1150R-ville. Kinda airhead style. There's something joyously gritty about it all, no more new car smell for our Roadsters and Rocksters, just greasy satisfaction that we're fixing things and figuring out how these machines really work.

Well done vexlak - high5.

[boxermania]

As my good friend and cohort CycleRob so stated I had suspected an excitation issue when the alternator started charging upon removing one of the wires....I never gave second thought to a shorted wire on the idiot light would have been the cause.

I love this thread, because we have risen to a level of experimentation and information sharing, IMO, above other BMW forums.