So when I bought my 2008 XK last January. I had all the usual bad battery symptoms and after a couple of battery replacements, 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 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, 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 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 says the car is putting out over 100 amps idling at rest. "well within normal range" says the dealer. (OEM top end for amps is supposed to be 130).

I 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?