Battery isn't the problem. Possibly your dealer is incompetent.

There has been a known issue with the ICE software draining the battery.

My 09 is on its original factory battery, despite Canadian driving conditions. The battery is big enough and of good quality. If your XF is killing batteries there is a software issue that needs updating.

 

I had an "infotainment control module (ICM) and/or instrument cluster (IPK) upgrade" in October 2011. Not sure if this would be the software reprogram that you're referring to.

 

I had the software update done and my battery still went dead twice in 2012. Both times, I took it to the dealer and they found nothing wrong, and said the battery was fine. I also took the car to Autozone and had them check the battery and it was fine.

I eventually figured out what causes the battery to go dead on my car.

1. I drive the car just 2-3 miles each way on weekdays, so the battery doesn't get a really good charge.

2. I leave the car unlocked in my garage. If I open and close the door or trunk to get something out of the car, and I do this more than a few times over the course of 3 days when I'm not driving the car, the battery goes dead. Same thing happens if I pull the car out of the car to wash it, then back in the garage, then open the door or trunk a few times. Leaving the car idle for 8-10 days with no one touching it doesn't cause the battery to go dead (I've done this several times with no dead battery).

My concusion is that when you open the door or trunk, the car goes into "ready" mode and starts consuming power, draining the battery, and it stays in this mode for around 15 minutes. That is how long the screen saver stays lit, so that's my guess as to duration of this ready mode. If you close the door and lock the car, everything shuts down.

So, now, I'm more careful about how many times I open/close the door or trunk if the car is going to sit in the garage for more than 3 days.

If your pattern matches the above, that's your explanation for the dead battery.

 

Proximity to the key fob will "awaken" the car, ready for pushbutton start. Just opening a door or trunk without the key fob anywhere near the car should not awaken the car, just the courtesy lighting. Even if the car has the fob nearby, everything should remain "off" as no accessory can be operated unless the START button is pressed. The exception is that the ICE remains active for a short period after the ignition is switched off in order or you to continue using your Bluetooth phone or listen to the ICE.

5-10 minutes of driving should recharge the battery unless you start the car in very cold conditions, parked outside in winter for example.

The software update was supposed to correct the battery drin problem.

 

If the software update is supposed to fix the drain problem, I'd like to know what that update is.

The battery drain is also a very common issue among new XJ owners. There are threads on this XJ forum, as well as the British Jag XJ forum with no real solutions.

After getting repeated "low battery warning" on my 2012 XJL, I checked the battery draw under various conditions. When opening a door without starting the engine, both the instrument panel would light up and the touch info panel would come on and they would pull 16+ amps. When I was trying to load my CD hard drive with the engine off, it was pulling now 26 amps. Those are HUGE current draws.

Anything more than just a very few minutes with doors open, computers on, will result in low battery warnings for the XJ. I have not experimented with our new XF yet but, assume something very similar since it now shares much of the software.

I think Jaguar really made a mistake in engineering the electrical systems on these cars. No way should you be getting so many low battery alarms and have so much battery issues.

Albert

 

This confirms my theory about opening the door and then letting the car sit idle.

 

I drive my XF a lot more than before. It’s on the road almost every day for about an hour, if not more on the weekdays. I always keep the doors locked and very rarely open them without starting it. I've never had any low battery warning or any other warning indicators activate prior to the XF failing to start.

In addition to this reoccurring issue, I’ve experienced several others, such as my radio's volume significantly changing from quiet to loud, a noticeable loss in acceleration, and the vehicle stalling while in drive, none of which have resurfaced at this time. These issues were brought to my service dealer’s attention but they could not duplicate any of them. I’m not sure if any of these issues relate to the bigger problem, but it’s become a significant reliability concern for me.

 

Ah yes, you drop off your car at the dealer, go back and forth twice, then when you pick it up you get the dreaded "Unable to Duplicate Condition at this time" -- translation: complete waste of your time.

You mentioned that JLR said something about a buy back. Given all the problems you'r having, I would press on that. Good luck.

 

I think the battery low indication is tied to the amount of time the car has been idle, not solely to the actual charge of the battery. I keep mine on a Battery Tender when ever it will sit idle for a few days or more. My car had been idle for about a week when I took it off the Battery Tender and got in it to pair a new phone. The instant I turned on the car (not started it) I got the low battery warning and prompting me to start the car within a few minutes or it will shut its self off.

 

I do not think that it is strictly the time the car has been idle. Of course, it is related because the longer the car sits without charging the more drain will occur.

The low battery indication IS tied to the actual charge of the battery. There is a small CT (Current Transformer) mounted on the Negative battery post on both, my 2012 XJL and XF, that actually senses, measures and transmits to the vehicle computer the exact amounts of charging current inflows and load current outflows. From those readings the computer will add/subtract and issue the warning.

It is a sophisticated system but, IMO, a bad design for using so much currents for very basic, non-running modes. Forget about listening to your audio system with the engine off. It is ridiculous for having to run a huge V8 engine if wishing to use any of the electronics or wanting to leave the door open for any length of time.

Albert

 

It doesn't matter how many times you've boosted a car in 40 years.

If the in car system is at 12 volts, then there is no need for a boost. However, since there is a need for a boost, it is not at 12 volts. At that point, yes, the booster, whether it be another vehicles, a booster pack, or a boost charger, will start charging the depleted battery as soon as the hookup is complete and current flowing.

Following from the previous passage, in the real world it is often quite helpful to let the donor partially charge the depleted battery before attempting a start. This is because the booster cables or the clamps on consumer grade booster cables are often inadequate to carry the full starting current requirement. The proof of the pudding is the observation that if the starter just groans on the first try, a subsequent try is often successful with the starter going full chat. The depleted battery didn't get better all by itself. It took a charge from the donor.

Right. But, it is still helpful to have the patience to wait a decent period for the depleted battery to come up a bit. The problem is that the donor driver is often in a hurry, so it requires some sweet talking to get the required cooperation. As a matter of fact, it is possible in dire circumstances to bring a battery to starting voltage by jury-rigging a charge circuit out of lamp cord and waiting long enough. Not ideal, but if stuck in the middle of nowhere without booster cables in either vehicle, it will work.

 

At minus 35C not too many of us would find this advice very appealing.

Once the dead car has been started its own alternator will do all the charging.

Waiting is completely pointless.

Professional boosters do not follow your advice.

 

Professional boosters likely carry an ultra-heavy cable the size of a welding cable to accommodate the approximately 400 Amps of starting current. Plums is very correct, your "normal" jumper cable is unable to carry that much current. Thus, you do need to wait for a while that it takes to transfer enough charges into the dead battery in order to get a successful start.

I would make one further suggestion when it comes to jumping an other car. Personally, when I provide jump to an other car with dead battery, I assume that it may be dead due to a "dead short" somewhere in the electrical system. Thus, I completely shot my engine off and shut the accessories off, as well. That way the worst that can happen when I make the jumper parallel is to blow up my battery if it is connecting into the other vehicle's dead short. If you leave the engine/accessories ON, you run the risk of the short damaging your own electrical system, computers, all. I think this is something to think about...

One more word; don't trust that your vehicle's fuses will save your electrical system from terminal damage from the other car. Fuses take some time to melt and blow and before that the damage will be done. As an Electrical Engineer I have seen MANY examples for fuses taking too long to blow and extensive damage occurring in the "protected" equipment.

Albert

 

"Blow up your battery?"

If that is a perceived risk shutting off your engine won't help much.

But, by all means take your time boosting a dead car. Never happens here and our starting issues are much more demanding than yours.

I repeat, it is totally pointless to wait before trying to start the dead car. The donor car is capable of providing full starter current and, once started, the dead car's alternator is capable of producing all the charging current that dead battery can take. You know both cars deliver a maximum charging voltage of just over 14 volts. Connecting them in parallel, as you must, will result in a maximum charging voltage of just over 14 volts. Try it. Alternators have way more charging capacity than any single car can use. 14 volts is the designed controlled voltage, +/- a bit.

Quite funny you mentioned the large cable size on the booster van: they are also 10 meters long!

The cable size is pretty much irrelevant as the limit on current flow is the size of the spring clamps. Now those are large surface area on booster van equipment and thin toothed clamps on the 2 meter long portable booster cables commonly used up here.

 

I did not say that shutting off the car would prevent a blown up battery. Please read with more attention. What may blow up the battery is if you are connecting it to a "dead short" A "dead short" will pull huge amounts of current from the donor battery (try Ohms Law), which, in turn, causes a sudden increase of heat inside the battery, which in turn could release large amounts of gases as the electrolyte boils, which in turn would blow the sides or top of your battery. That is the main reason experts advice never to make the last parallel connection on the battery itself but, away from it on the chassis, so if/when it blows it will not spray sulfuric acid into your face.

Shutting the car and accessories off is an extra step of caution to reduce to risks to your own car's electrical equipment. Yes, your battery is actually at risk any time you connect to a dead battery without knowing what caused the dead battery.

Not sure what you are trying to say about the charging voltage; that has nothing to do with the jumpering process. If you are implying that the average donor car's alternator is capable of providing sustained 400+ amps of starting current, you are wrong. Only the donor BATTERY is capable of providing that.

With a healthy donor battery, you can shut the engine off safely and still provide a few minutes of equalizing current to the dead battery before attempting to start, still aided with the average sized jumper cables. I am surprised that you apparently have not experienced a failed instantaneous startup when you use your average small jumpers. I've seen it numerous times, except when the low battery had enough residual charge to aid the flimsy jumper.

I have some welding cable - made into jumpers but, due to its weight and mass I do not carry it in my cars. It is for home use only. I only carry jumpers that generally require a bit of charging and waiting for a jump.

Albert

 

I just call AAA!

 

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I Know what your problem is but I'm not going to tell you. Techs within the Jag community keep info to themselves, so unless your battery is bad, then there is a drain. But chances are your battery is straight up bad. Jaguar doesn't make their own batteries. There is really only a few battery manufactures in the world. They just slap different stickers on the batteries. How often do you drive the car anyway? Does it sit? Was it sitting for more then a few days before you started it?

 

Your car being left unlocked vs locked has the same drain level. A normal XF goes to sleep after about 2 minutes. The drain is 20mA. I've been down this road before so. Unlocked or locked doesn't make a difference. There is another reason it dies, but it's too involved for me to go into details on jaguarforums.com. I also don't want to reveal info so that you would not have to take your car into the dealer or Jaguar Specialty shop for work.

 

I notice that when I open/close the door without locking, the screen saver stays on for 15 minutes. When I lock, it goes off immediately.