Battery not lasting very long!

[not-so-fast-ed]

I added the accessory plug to mine, just behind the battery cover on the left side, in order to keep the battery topped up with a Battery Tender & allow me to add additional electric goodies in the future.  
Here's the link to realoem.  the kit should be available for the dual shock models as well.

http://www.realoem.com/bmw/showparts.do?model=0462&mospid=47892&btnr=61_0255&hg=61&fg=30

[montmil]

Beautiful rig, Scotty!  [smiley=thumbsup.gif]

[diggers]

I just did the multi meter thing. I got 11.3v turned off.  Once the bike was going it rose to 12.4v at about the 3500rpm mark.  From what I'm told it sounds like not enough alternator action is happening and therefore it may be faulty.  That sound correct to you knowledgable guys?

[Bob_Roller]

Before I started replacing costly components, I would follow airhead's advice on checking electrical connections in the charging system for condition (corrosion, loose wires in crimped on connectors, loose connections where they are held on with fasteners, etc.) .

When I lived in Chicago, when I was using my R65 to commute to work, it was 7 miles and 15 traffic lights, if I didn't take the bike out on my days off and run it at highway speeds for an hour or so, or put the battery on charge, on the 8th work day, the battery would be discharged to the point that the starter would not rotate.

Since moving to Phoenix 15 years ago, my work commute is 12 miles, with 10 of them urban expressway, and I have not had a problem with battery charging with this 'new' commute.

[diggers]

Thanks for the advice Bob!  Will try that next.  Cheers

[airhead]

I just did the multi meter thing. I got 11.3v turned off.  Once the bike was going it rose to 12.4v at about the 3500rpm mark.  From what I'm told it sounds like not enough alternator action is happening and therefore it may be faulty.  That sound correct to you knowledgable guys?

Sounds like you have the basis of a decent fault to look for there. My guess would either be a duff diode board, bad brushes, or a stuffed regulator.
Do you have access to known good examples of these to temporarily substitute (one at a time)? If not, here is a download of the BMW procedures for diagnosing further, noting of course your possible limited experience working in this area. If so, get back and we can lead you through.

http://www.mediafire.com/?3m1hy4mpwsi

Bill........................;-)

[diggers]

Cheers Bill.  I'll print off the download and have a go.  I'm already verging towards the "time to go to an auto sparky!" position, but I'll have a crack and see how far I get!  

[diggers]

Hey Monte, I've made some progress:  I found the blue connector box thing under the seat!

[montmil]

Hey Monte, I've made some progress:  I found the blue connector box thing under the seat!

Outstanding! You've got power there for a battery tender or similar. Just don't post a photo of it.  

[MrRiden]

I just did the multi meter thing. I got 11.3v turned off.  Once the bike was going it rose to 12.4v at about the 3500rpm mark.  From what I'm told it sounds like not enough alternator action is happening and therefore it may be faulty.  That sound correct to you knowledgable guys?

I noticed in the trouble shooting download that if the voltage reading is significantly below 13.5V to examine the cable connection. Thats where I'd start.
Bill, Have any more gems like that download hidden away?
rich

[diggers]

Well I'm not exactly sure I did what I thought I did, but I think I managed to test the output at the diode board and also the output from the D+ wire that goes to the regulator.  Output from both of those was 11.3v, which is the same as the battery output.  I think that means that both of those things are ok, leaving a faulty alternator as the issue.

Anyway I took it to a motorcycle auto sparky today.  I'll let you know what the outcome is.  Along with a bill I've actually gained some knowledge about the electrics of my machine!  Thanks to you guys who have helped me out with advice and tips.  From my perpsective it's much appreciated!  I often marvel at the ability to exchange tips, chit chat and nonsense with people from all over the world that I've never met, but feel a kindred spirit with!  Cheers!

[diggers]

The auto sparky did his thing and told me the voltage regulator had done its time.  Alternator and diode board are OK.  Come in one new voltage regulator!

[Bob_Roller]

Diggers, it's great to hear that someone actually found your problem that wasn't well versed on BMW motorcycle charging systems.

At least it won't cost you too much to replace the regulator, and it is a quick replace type part.

I have never seen in any troubleshooting guide, about a voltage value of the voltage that leaves the regulator and goes to the brushes in the alternator.

Seems to me that if at peak engine speed, say 4,000 rpm if the voltage being applied to the rotor is insufficient, or below a certain value, it would immediately point to a regulator problem.

All I can find is a reference to power, or voltage available even in Motorrad Elektrik's charging manual.

Anybody ever hear of a certain voltage value before ?