Does anybody have any service data information, I got an '09 Jaguar XF. I just kind of need to know if the alternator should constantly be charging the battery over 14 volts or does it sometimes drop the 13 volts depending on if it needs it or not?

 

Does your car have BMS? I think all modern Jaguars do.
If so read about BMS systems and no the charging system does not operate like that anymore at all.

Do you have a problem?
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It does have the BMS....just changed the alternator, battery and the neg cable with the BMS sensor...car died on me a few weeks ago.

 

Read this & take note of the fuselink info because if it fails the charging system will revert to charging at 13.7v
​​​​​​https://ibb.co/2sKSSHt

 

Just read the data, so it looks like is it supposed to charge between 12.6 and 15 volts with the alternator running? Or is that just when it calibrates?

 

Well yes and no? With a BMS system the voltage will vary depending on what the BMS is doing. So you might see those numbers and you might not.
There is no standard anymore. I run a plug in volt meter 100% of the time in my XJ. So I know exactly what the voltage of the car is at all times. It should in general terms start out low when the car is started then rise as the system recharges the battery but as you have read with a BMS is just not that simple anymore.

But since I have been running this I know how the car reacts so I have a better feel if something is not right. Your numbers don't sound out of line and unless you have some errors or dash lights I think your system is operating correctly?
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