What volts should my battery & alt read

Hi,

I've got a 1.5 JB engine and was just wondering what voltage the battery and the alternator should read when the alt is charging the battery? And what would cause the voltage reading to fluctuate at both the battery and alt

Thanks

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The normal voltage on the battery sitting not running is 12.5-13V from Positive to Earth.
The normal battery voltage when running is 13.5-14V.
The Alternator should be putting out 13.5-14V. with nothing running electrically.

Which alternator do you have the Motorola style with a PLUG and  the Regulator is flush to the Case.  



Or

The Bosch 2 stud One large and one small with a exposed regulator assembly?



The second part have you verified that you don't have bad earths, or main leads to your battery?

Do my quick test to check your grounds.
https://www.volkswagenownersclub.com/threads/brianos-quick-grounds-test.134637/

If you see vast improvements then you should replace your battery to frame and frame to Engine earth.

Here is a good tune up for the Bosch 2 stud.
https://www.volkswagenownersclub.com/threads/mk1-bosch-posted-alternator-tune-up.135143/

Removing the Voltage Regulator isn't a bad thing, and you can check your stators (copper bits at the back of the alternator) for wear and cleanliness.  

Thanks for the detailed reply. I'll check which alt I have and follow your suggestions