Hello - I have a 2007 2.7 XJ X358 I use this very little and disconnect the battery when not used, When I last connected the battery it seemed to run ok. However last time when it was stationary without the iginition on I heard a clicking sound around the r/h rear of the car, I then left it and disconnected the battery a couple of weeks back and today reconnected a fully charged battery and the boot lights are flickering and whereas the cars electrics usually sound as the car "comes alive" and the alarm reqs unarming via the fob, none of this has happened. It is not the car battery as I have 2 and tried both. Please any ideas - any assistance will be very much appreciated

 

I have just checked it again - reconnected battery and the clicking sound is from the rear fuse boot in boot Maybe a relay. as well as some clicking sound elsewhere in the rear r/h - the boot light is flickering so it appears that for some reason something is wrong- to confirm the battery is fully charged with no issues.

 

I would suggest not to keep the battery disconnected. Your batter will still lose charge over time, and the battery may not last as long. Also you have some electronics in the car that need power (I.E. clock, radio, emergency brakes, and others items.) My suggestion would be get a proper battery tender. Look a Jay Leno, He has many cars, and some sit several months and never get driven, but all are on battery tenders. I have 2 Jaguars that I take mainly to concours show,and they may not leave the hows for a few month, and one is a 2009 XJ8 still with its original battery. I have been using a battery tender for years. Also you should be starting your car and running it every few weeks till it get warm to move around all the fluids. I will take mine around the block at lease once when I start them. Here is the battery tender I use, and yes it is the same as what Jay Leno uses on his cars. This is a CTEK, and it keeps the battery at the proper level, and even shows you if the battery is having issues. It can even recondition the battery if it is still good. Hope this helps

 

Sorry to read about your truly depressing saga. I remember a few years ago visiting a Jaguar dealer showroom. All display cars had extension cords running to them connecting them to battery chargers. I asked a salesman for the reason. He told me that the frequent door openings by potential buyers ran the batteries down.

Yes, in my 6 Jaguars of late I had plenty of those "Battery Low" warnings after having my doors open only for a matter of minutes. I also had several dead battery issues, very similar to yours. I begun investigating by connecting a DC Ammeter in series with my battery negative while the car was parked. It showed a large 15Amps+ draw every time a door was opened. It also showed that after shutting the car down and locking it, the battery draw continued for several minutes, shutting off in stages, not all at once. On two occasions I captured a condition where the last stage of the power shut down procedure failed to finish and hung up. The ampere draw was under 2 amps, perfectly matching the symptoms of a battery going dead after only two days. Further testing proved that it was the part of the Entertainment System that failed to shut off. Of course, the dealer, just like in your instances, was unable to find anything wrong, not surprisingly because the hung-up was unpredictable.

After I presented my findings to the dealer, they checked their factory recall notices and realized that, indeed, there was a recall for that very issue. They simply needed to download the newest software and the dead battery problems were solved. What was NOT solved was the unreasonably large current draws every time someone opened a door, or turned on the radio, or woke up the system computers for any reason.

My suggestion is that you take the investigation in your own hands. Use an ammeter to document the current draws on a parked and locked car. When you do find a rogue draw the amount of current could be used as a clue as to what component is misbehaving. A normal current draw of a locked up car should be no more than 40 - 80 milliamps. (0.04 - 0.08 amp)

 

How do you know the battery is 'fully charged'? What is the voltage across the battery terminals with the ignition in the OFF position when checked with a voltmeter?