I originally posted this in the XK-XKR forum and never received any feedback. I am hoping that since it is a tech issue, I might get assistance in this forum...

-----------------------------

When I bought my 2008 XK last January. I had all the usual bad battery gremlins and after a couple of battery replacements (first repacement battery was faulty), everything finally worked out. Since then I have got into the practice of putting a battery charger/maintainer on the car every friday evening when I get home. This is where it gets a little interesting....

I drive about 30 minutes each way to work. If I attach the charger/maintainer after a normal five days of commuting, it takes 12-15 hours for the car to completely charge. However, if I only drove let's say two of the five days and the car was left in the garage the other three, then it only takes 3-4 hours for the car to completely charge.

If I put my Ford truck or Land Rover on the charger/maintainer, it never takes more then 2-3 hours for either of those vehicles to charge.

I have had the car checked twice for parasitical draw. My dealer says there is virtually no draw. In fact, better he says then most Jags he has checked.

I also had the dealer check out the alternator. First he only checked volt output. "Perfect 14.5 volts after start-up", says the dealer. I brought the car back and insisted he check amps. After taking over a day to FIND an amp meter, the dealer checked the alternator and said "we got your alternator to put out over 100 amps, well within normal range".

I checked and discovered OEM top end for amps is supposed to be 130, so I just don't know. I still think something is wrong. I do not believe the car should be discharging the more it is DRIVEN...

Any thoughts?

 

There is a draw somewhere. I would check all interior trunk or under bonnet ,glove box lights as if left on with a slight draw 24-7 could be your problem.