3 months ago the battery on my newly purchased second hand xf died and the car wouldnt start so the technician replaced the battery and all was good.....

Until this morning where the car wont turn on, start and i can no longer even lock the car using my key fob.

The car is used on a mostly daily basis but the car was sitting in the garage for 2 days since i last used it.

I always keep the car locked and the key fob is well out of range. This is the second time it has happened and im sure the battery wasnt the problem as it was brand new as of 3 months ago.

I love the car but its so unreliable. Any one have any idea what the issue is? It will be taken to the Jag Service Center in Auckland tommorow.

 

What daily mileage?

 

If you are making really short "almost daily" trips it may not be enough to keep your battery charged. These cars have a great deal of electronics and the battery has to be fully charged. I would suggest purchasing a battery tender and keeping it hooked up and see if that solves your issue. There has been many threads on this subject on the forum.

 

Im not sure about daily milage but in 3 months the car has been driven 6,000km. I paid good money for this car and i dont expect it to drain its battery after 2 days of sitting idle. I have a feeling that their is a major fault in its electrics somewhere.

 

We'll guess the daily figure, then.

You'll have to measure the drain and if too high hunt for why.

Or take it back / claim on warranty you presumably got.

 

Sounds like you have something keeping the car awake?

Open the trunk and come back in about 45-50 minutes.
Is the trunk light off?

You might need to measure the current drain as the car goes to sleep. It should ramp down over time until about 45 minutes and then it should go off.

Let us know what you find. Especially the amount of current drain you have. It could be from a number of places or the car could be disturbed by something and that starts the 45 minute count down all over.

Do you have any after market stuff like chargers or radar detectors?
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It was jumped ok by the aa mechanic today and now its with the jag service center. I think this car as it is uk built model sent to japan and then imported to nz it might have missed the 2010 infotainment update. Could this be the issue that drains the battery

 

I leave the AUX Plugged into the slot in the jag but never leave any device connected to it

 

A battery drain problem like you describe can be a little tricky to find, but a good automotive electrician can find it fairly quickly if it is happening consistently. Although it will cost some money to fix, I guarantee you it is not a "major fault". Neither is it normal behavior, so it is just one of the things that will happen to any five year old car with sophisticated controls.
Please keep us posted as to what they find.

 

After day 1 they have found nothing so far, will do more tests tommorow

 

There are some battery failure modes that can match your symptoms including some that are affected by vibration. (Internal separator failures). So, give them a break if they are not finding it immediately.
I know, it is easy for me to advise chilling out when it is not my Cat that is misbehaving!

 

There was a weird knocking or tapping sound coming from the bonnet once the battery went out, and what exactly does the internal separator issue mean, should i mention it to the mechanic tommorow?

 

The separator is just a part of the battery internals... I am sure the tech is considering a bad battery.

I assume your weird sound came when you tried to start the car. That was just the solenoid cycling because of low voltage.

As you seem to realize, you have seem to have a low battery. That is either 1) because something is discharging it- which is fairly easy to find, 2) it is not charging properly, or 3) the battery is failing. And, yes, although rare, new batteries can fail.

If the Auckland Jag dealer does not jump on the problem pretty quickly, find a auto electrical specialist.

 

I think the issue is that whatever seems to drain the battery does so randomly, ie unluckily whenever the mechanic is testing it, it works ok, but on other occasion there is something that intetmitently is draining the battery.

 

Well, then, you are going to have to do some sleuthing on your own unless you want to pay the tech a bundle. I suggest you get a little log book, and buy an ELM interface module and appropriate software to read the system voltage parameter. Then begine noting the on but no crank voltage with and without the lights o each time you get ready to drive the car and when you stop.. Notice that the interior map lamps shut off each time you park the car. Notice any peculiarity when you get in each time.

I bet you figure it out what is doing it pretty quickly. The only challenge then is figuring out how to fix it.

Just for fum you might ask the tech what the quiescent current draw was after the car was shut down for 30 minutes. The quickness and confidence of him to give a valid answer is much moire telling that whatever value he might say! If he does not offer an answer readily, find an automotive electrician.