WTF?

I left the car on the two post lift like I have done many times before for a week and yesterday I dropped it down and it was deader than dead. 3.6 volts.

Obviously something drained it while up on the lift. It has coil overs and the air suspension is disabled. The battery is 4 years old and has not given my any issues in the past.

Still trying to resurrect the battery - I may or may not be able.

Obviously a drain - has any one had this happen to them? Battery goes from healthy to deader than a door knob w/o any apparent reason?

 

Sounds stupid, but I was looking something up in the owners manual and read if the key is left in position I or II, it will drain the battery. I know the dome lights will go off to prevent this, but the ignition would kill it fast. Or it's time to start pulling fuses, to find the drain. Never had a dyeing battery go that low on it's own. Your right, 3.6 is drop dead.

 

I managed to recover and recharge the battery and put the car back on the lift for another 4 days. No issue when I took the car off the lift. The only difference is that I did not leave the key in the ignition as I did the first time - I wonder if leaving the key in the ignition (in the off position of course) sucks battery juice.

Took the car off the lift and have been driving it w/o any issues the last few days.

 

Though I am not sure if the XJ suffers from the same, a key left in the ignition of an x100 is a quick way to drain the battery. There is a small flap over the ignition cylinder key hole that you push the key through. With the flap open it prevents the car from going into sleep mode, regardless of the ignition position. Even if you have the key out, there is a possibility of the flap sticking open. Lubrication generally remedies this.

 

He's right. I forgot about the flap

 

Mystery solved then! Thanks!