Motorcycle voltage question. NGC

[drw916]

Took my 2015 BMW R1200RS out for a ride Saturday.  Checked the dash voltage and it was running between 15.5 and 15.8 volts.  Stopped and turned off the ignition.  Started it back up and it read 14.2 -14.4.  Once I got moving, it soon went back up into the 15's and hit 16.0 briefly.

I called my local BMW shop and their answer was BMW's are designed to run a lot of extra electrics.  I call BS to that being the reason, but before I take it in under warrantee, I wanted to get the opinions of others here.

Never had the bike show high voltage before in 10,000 miles.

Thoughts? Ideas?

[oldbike54]

 Sounds like the beemer shop needs an education in how electricity works .

 Dusty

[ITSec]

The bike should produce lots of amps (if needed for accessories), but the volts should always be in the standard range for a 12v system. Sounds like a version of 'go away, little boy - you bother me!'

[Kev m]

Interesting in that Guzzi specs CLAIM that they designed the early 1TB motors in the Stone/Special/Racer to supposedly operated up to 15.0 volts regulated, and a bunch of them seem to have tested higher than that in the past year or so.

[acogoff]

     I would be tempted into leaving it run when it is showing the 15+ volts and put a trusted meter across the battery terminals and  see if it is actually charging that much before proceeding.

[leafman60]

     I would be tempted into leaving it run when it is showing the 15+ volts and put a trusted meter across the battery terminals and  see if it is actually charging that much before proceeding.

Ditto

Modern BMW gauges are known for error.  Most of mine are not accurate and that includes, temperature, fuel and voltage.

Check it with a quality voltmeter. Chances are good that you are fine. 

[Kiwi_Roy]

     I would be tempted into leaving it run when it is showing the 15+ volts and put a trusted meter across the battery terminals and  see if it is actually charging that much before proceeding.

 :1:, it might be resistance building up in a switch, the Guzzis usually show low in this case but who knows what those crafty Germans are up to?

[atavar]

Also check the battery terminal connections themselves.  The best way I have found to do this is to take a voltage reading from the lead part of the terminal to a copper part of the cable connected to it.
If you get any more than trace voltage clean and redo that connection.
The same method applies to ground connections. Take a voltage reading from copper on the cable to some point on what the cable should be connected to (like frame or engine block).
Again, if you get more than trace voltage (like .05VDC) clean and rework the connection.
The regulator may be trying to overcome a dirty connection some where.
No connector anywhere on the bike should have any voltage from one side of the connector to the other.  There may be 12V or ground there but the difference from one side of a connector to the other should be zero.

[Wayne Orwig]

Took my 2015 BMW R1200RS out for a ride Saturday.  Checked the dash voltage and it was running between 15.5 and 15.8 volts.  Stopped and turned off the ignition.  Started it back up and it read 14.2 -14.4.  Once I got moving, it soon went back up into the 15's and hit 16.0 briefly.

I called my local BMW shop and their answer was BMW's are designed to run a lot of extra electrics.  I call BS to that being the reason, but before I take it in under warrantee, I wanted to get the opinions of others here.

Never had the bike show high voltage before in 10,000 miles.

Thoughts? Ideas?

15-16V AT THE BATTERY will cook it after a while. The shop answer is nonsense, as it is CURRENT that is needed for the extra electrics, not voltage.

1) Measure the voltage AT THE BATTERY. The dash is likely lying.
2) If it has changed from what it used to be, look for a poor connection, especially at the main battery posts. If may be a sign of a high resistance in the system, including simply an old battery with high resistance. If the alternator has a separate voltage sense line, it may be the connections on that line are going bad.

[atavar]

My Cadillac typically runs 15.0-15.7V ..  the users manual states this is what I want.  Of course they do specify a specific DelCo battery with no cross reference or substitution..

[Tom]

Definitely, digital multi-meter at the battery to check for voltage.  As stated previously gauges on the dash can be wrong.  Same as the ones on Guzzis.

[atavar]

Yeah, the Caddi system is too smart for it's own good. 
If I just took it off the maintainer it runs at 12.7-12.8 .
Normal daytime summer cruising is 14.3-14.7 . 
High beams or sub zero temps or AC on high or speed over 75  it goes to 15+