I have a 2012 XJL. Does this model have an auxiliary battery and if so where is it located.
TIA
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Historical, your car does NOT!!! have an auxilary battery. The second battery is only on a select few year cars (2013-2015) that had the START-STOP feature.

 

Great to know.. Thank you for the quick reply.

 

What could be some of the causes of the low battery light coming on?
I have a brand new battery and even after a 400 mile journey when i had the door open for a short period of time the low battery light came on again.

 

When you say battery light do you mean the message 'low battery' or the red battery symbol on the cluster display? and when is this coming on - if the red symbol is ever on when the engine is running then you have a charging fault but it does come on as part of a self test before starting the engine.

Battery management on pretty much any Jaguar post 2006 is absolutely sh*te - my XF was the same, couldn't even sit waiting for somebody with the radio on for more than 10 mins without the car bitching. I've had the car complaining about a low battery within 24 hours of an 800 mile round trip. From what I understand Jaguar measures battery performance by discharging the battery periodically but it doesn't tell you it is doing so - absolutely stupid idea.

In the XF I had to keep a Lithium boost charger in the back when travelling because more than a couple of weeks in an airport and it was touch and go whether it started, the first thing the car does is start everything you don't need as soon as it detects the key, I put a recording meter in series and measured an 8A draw for 20 minutes after locking the car, why they can't just shut everything down when the car locks is beyond me, if you don't lock the car the stuff will shut down but it takes a long time to do so.

If I had one gripe about these cars their battery management and demands would be top of the list. We have a Passat est and that can sit for 8 weeks and still start, can listen to the radio or music for hours with no complaints at all from the car and it still starts.

 

I’m sorry I did not specify. I am actually getting the message “Low Battery”. I do agree with you its quite frustrating but I guess just one of those gremlins in these otherwise Spectacular vehicles.

 

Yes Ben makes a good point about the BMS and the electrical system in general. Jaguar with the 2013 model introduced a whole array of electrical changes including changing suppliers for the ECM. They went from Bosch to Denso and added a lot of features plus you get the improved 8 speed automatic.

I know my 2014 XJR's electrical system has been completely trouble free compared to what I have read on this forum!
I still have the factory battery and yea it's now over 9 years old. I have left the car sitting for 8 weeks at the airport because of family troubles and had no problems and it started right up! I have had the battery unhooked many times with no problems.

This is why when people ask I try to point them to a 2013 and up model. They made some excellent improvements!
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Ive read somewhere that locking the car with the key fob twice will shutdown the entire electrical system so there is no drainage. Hitting the lock button just once keeps some open and can draw power.
Could there be any truth to this?

 

Hi sure I have read on here that it takes 30-40 mins for jaguars to go into "sleep mode " . Have a look inside the car after 20 mins you are wanting to look at the hazard warning triangle button , if this is still illuminated after 20 mins then it's drawing power , a well know topic on the Ftype section on here

 

To address a couple points. I had a 1st year XF. played the radio nearly all night after surviving a hurricane. (Turned off everything possible.) With my X351 series XJ’s (Had two) couldn’t go a half hour. Much more electronics.

Double locking DOES lessen unnecessary battery drain but our car’s STILL react to the key fob transmission. And ‘surprise!’ this can travel much farther then you ever thought possible. I have an office. I often park across a (One lane, one way) street from our (pull-in straight) parking in front of our building. My office is in the back (Upstairs) of this 20,000 sf (Approx.) building. My trunk was open on my XJ yet it was still locked! I “butt” signaled my boot! And I sit near the back wall of my office on the back side of my building!

I made my own faraday cage out of an empty Altoids tin! I’ve tested it, with the fob inside, (In my picket) I’m unable to open my doors even next to the car! This also thwarts would-be thieves using the fob’s signal & a RFID amplifier to ‘fool’ your car that you’re close with your key!

 

That’s very interesting!! Thanks for the info.

 

Can confirm, my 2010 battery drained from < 2 weeks of sitting. Before that it was driven daily. Put the CTEK on it and it’s back up and running.

Love the CTEK, I’ve even used it outdoors in the rain (good weather resistance)!

 

I have left my 2011 XJL in the garage for a couple weeks before. And it usually gets driven only a few times in any given week. Never had a problem with drainage, but I always double lock it out of habit.

That being said my battery is getting old at about 6 years. Not original it is a NAPA brand AGM. I know I need to replace it soon cause I am seeing a few gremlins I am pretty sure are from lower voltage. And the handy readout I put in the trunk is displaying a resting 12.2 volts.

 

Funny you should say that . I have had 3 x351 s and all show 12.2 volts at resting . I put all inc current on full 8amp charge over nite every 2 weeks to keep battery healthy I do not trust ctek as one failed on me years back but use a great ring brand charger

 

Thank you, I’ll check it out.

 

Whenever I park my F-Type in the garage I hook it up to a battery tender/maintainer.
Not a CTEK but a decent and powerful one from the local auto parts chain which has served me well in the ten or so years I have had it.
The battery in my F-Type is the original AGM now over eight years old and it is still going strong.
Thing is, within about an hour of shutting down and locking the car my battery reads 12.2 volts and always has.
I did some research on this a few years ago and figured out this is the "resting" voltage, in Jaguar speak called "quiescent mode", invoked by the BMS (battery monitoring system) in other words normal and nothing to worry about.