2008 R1200GS alternator voltage?

[landmarkjohn]

GS911 is telling me alternator output is 10.69 V, see first picture.

My Fluke meter across the battery with the bike running is 10.95 V, see second picture.

Is this in the normal range or should I be concerned?

Battery could be past its best but it did start the bike today after a couple weeks. Then it wouldn’t start it after leaving ignition on for a bit calibrating shocks.

I should add the alternator was spinning freely when I changed the belt yesterday.

 

[Santa-2512]

Is that measured across the battery terminals ?


If that's with the engine running I'd say it's a bit low mista

normal voltage with the alternator charging is 12-14.xx v ( well that's what I've seen on my meter/ my bike )

If thats engine not running , i'd say your battery voltage is low - ( normal is around 12V)

 

[Smiffypr]

Battery voltage is nominally 12v. Reality is that a charged battery should be well above 12, more like 12.5V and that to charge, the voltage should be around 14-15V.
You've got a problem, either with your meter, or with the alternator/battery.
I'm surprised it started.
My suggestion would be to disconnect the battery from the bike and charge it up for a day, then check again the battery voltage (meter probes on the battery terminals not the connectors), then start the engine and see what the battery voltage is.

 

[landmarkjohn]

Is that measured across the battery terminals ? Yes

If that's with the engine running I'd say it's a bit low mista Yes, engine running

normal voltage with the alternator charging is 12-14.xx v ( well that's what I've seen on my meter/ my bike )

If thats engine not running , i'd say your battery voltage is low - ( normal is around 12V)

I guess my real question is would a poor battery result in the GS911 recording a low alternator output?

(I hate buying a new battery at the end of the season to sit there for 5 months!! )

EDIT: Thinking about it a new battery is the lesser of two evils

 

[Mistacat]

You say you changed the alternator belt yesterday, was this because of the lack of charging voltage (Normally 14.3V) ?
Or did you do a random check afterwards , has the new belt been thrown or split.

 

[landmarkjohn]

You say you changed the alternator belt yesterday, was this because of the lack of charging voltage (Normally 14.3V) ? I changed the belt as old belt was split.

Or did you do a random check afterwards , has the new belt been thrown or split. I checked output because I had to jump start after running down battery doing ESA calibration.

I jumped started using a Halfords plug in battery charger / jump starter that has to be plugged into the mains to jump start. After jump starting I decided to check alternator output as I already had GS911 rigged up. And then tested across battery terminal also.

Maybe I fried an already poor battery.

 

[landmarkjohn]

Bearing in mind the bike is stored 10KM away from home, anyway I called in this morning after leaving BMW charger on overnight.

Looks as though it should start in the morning when I need to use it for the weekend run. I will bring mobile jump pack with me. 12.6 V with the charger still connected to aux port.

I will probe across the battery terminals again tomorrow when it is running. Interesting stuff, batteries on there way out etc, don’t you think?