"Gentlemen do not motor around after Dark" Joseph Lucas, the Prince of Darkness.

Well, he's still around on British Cars !
If you browse this Forum, you'll see that the most commonly-occurring problem with the Jaguar X150-series of XK and XKR is the Battery.
The following information has been distilled from posts over the last few years:
https://www.jaguarforums.com/forum/x...acement-54583/
https://www.jaguarforums.com/forum/x...lay-ups-73471/

Thanks to forum members Richzak, Clevername, Rscultho, Stuart S, WhiteXKR for their ideas, photos, and for reviewing this information. Mistakes are all mine tho !
And I suppose I should add the use-at-your-own-risk Liability Disclaimer here: As my Mother used to say to me: "Don't come running to me if you fall out of that tree and break your leg".


Symptoms:

Symptoms are 'weird things' happening - like:
* Touch screen 'freezes'
* One-touch window up/down is erratic (this was mostly a problem on the previous edition (X100) of the XK)
* 'BATTERY NOT CHARGING' displays in the Message Center between the Speedo and Tachometer.
The XK has 3 separate computer networks (High-speed CANBus (eg ABS), Medium-speed CANBus (eg wipers, lights) and MOST (Stereo/Nav) all sending messages to each other all the time. If any 'module' (basically a small computer) on any network gets a low voltage error, these messages get mangled or dropped and strange things result....

You should reasonably expect around 3 to 5 years life from the OEM battery, so if strange and intermittent problems are occurring, suspecting the battery is a good first step.
Start by charging it completely (see later for details). If that cures problems for a while, then they return, that is a good indicator of a failing battery.
Replace it before spending time and money chasing errors.


Battery Type:

The standard battery in the 2007-2010 XK is a Varta lead acid battery. The size is a 'Group 49' (that is an industry-standard size and mounting). It MUST be externally vented, because it is mounted inside the luggage compartment (see later).
However, numerous posters (Clevername, Rscultho) have had far better results with more advanced AGM batteries, and they are highly recommended.
However, there a Jaguar TSB (JTB00259) that instructs the Dealers to replace type-for-type, so that might constrain what a Jaguar Dealer will do.

Clevername posted:
Called Interstate tech support today. The Interstate AGM battery is MTP-49/H8A (the A designates AGM)
Note: According to Interstate, this is an older part number. The New number is MT5-49/H8

WhiteXKR found that Sears sell a Group 49 AGM battery, that fits the XK, even though their fitment chart does not list the XK.

AGM stands for Absorbed Glass Mat.
Basically a more refined version of the conventional lead-acid battery.
It has a similar kind of lead plates, separated by a fiberGlass Mat which Absorbs the sulphuric acid electrolyte.

They work in the same way as conventional (called 'flooded') lead acid batteries, but need a slightly different recharging profile for best efficiency.

Advantages:
* Sealed and don't leak, can be mounted inverted...
* Can accept a larger charging current
* Lower 'self-discharge' rate (ie if left unused they hold a charge longer)
* Usually higher capacity for a given size

Disadvantages:
* More expensive (25-50% more) Current prices at the Automotive stores (Firestone, Sears) seem around $200-$220 for an AGM vs about $130-$150 for the conventional Lead-Acid battery.
* Much harder to find...

For all those reasons, they're a much better solution for an infrequently used car, or one in a hot environment (evaporation of the electrolyte is slower).


Battery Replacement:

1. If there is any battery power at all, unlock the car to disable the alarm system (otherwise it will activate when you install the new battery !!).

2. Open the trunk.

3. For the Convertible only, raise the top, then remove the window-blind-like Luggage Separator from the front of the compartment. Better read the section in the owners manual and study the diagrams first: you have to tilt it towards the back of the car and pivot it out. (Owners Manual page 114).

4. Remove the floor panel over the spare tire.

5. Remove the four round plastic knobs at each corner or the vertical panel facing you at the rear of the compartment (the rear of the back seats) remove these by unscrewing counterclockwise and pull out.

6. The vertical panel will now come free when pulled to reveal the battery directly in front of you.

7. Disconnect Negative terminal (10mm bolt) on the left. (#1 in the photograph)

8. Disconnect Positive terminal (10mm bolt). (#2 in the photograph)

9. Pull the vent tube off, and save for the new battery.

10. Remove battery retaining plate (10mm security bolts x2) and swing aside. (#4 and #5 in the photograph)

11. Battery then simply slides out, new one slides in, and reassemble.

12. Ensure the battery terminal fit snugly all the way down (they are tapered) - there's a Jaguar Factory Service Message (SSM38790) suggesting this is a common cause of failure.

13. I always put some Vaseline or grease on the terminals afterwards to prevent corrosion

14. Don't forget to plug the vent hose into the side of the new battery – the battery MUST vent externally (even AGMs).

15. Reinstall the trunk liner, etc. For the convertible, reinstall the luggage separator. Ensure it is seated correctly - there is a microswitch on the LH side of the separator that will disable the convertible top open/close system if it is not located correctly (ask me how I know this.......)

16. You will probably have to reset some or all of these system due to loss of electrical power:

Electric Parking Brake (EPB). The message APPLY FOOT AND PARK BRAKE will be displayed when the ignition is next switched on.
Depress the foot brake and apply the parking brake. This is required to reset the parking brake system. The parking brake will now function correctly.
(Owners Manual page 139).

Power Windows anti-trap and one-touch open functions.
Ensure that the respective door is closed and, if fitted, the convertible roof closed.
Fully close the window, then release the switch. Again pull the switch to close the window and hold for two seconds.
Open the window fully and release the switch. Again press the switch to open the window and hold for two seconds.
Check to confirm the operation by opening the window and then use one-touch operation to close the window.
Repeat for the other window. (Owners Manual page 81).

The trip computer will lose all recorded trip data and all trip functions will be reset to zero. The vehicle total odometer reading is retained.

Reset the clock to the correct time (Owners Manual page 121).

Recalibrate the seat memory positions (driver and passenger seats) (Owners Manual page 119).

If the battery is disconnected for more than 72 hours, the radio preset channels will need to be reset.

If the convertible top does not operate (first check the luggage separator as mentioned above), you will need to manually fold it, which effectively resets it. According to the manual that's only an issue if power fails during operation.

The vehicle ECU may have to 're-learn' your driving characteristics
The engine electronic control system automatically adapts to certain characteristics of the vehicle.
When the battery is disconnected, these adaptations are lost.
On re-connection, therefore, some slightly abnormal drive symptoms may occur and the vehicle may need to be driven 16 kms (10 miles) or more while the control system re-adapts.

When the vehicle main battery is disconnected and then reconnected, the security system immediately returns to the state that it was when the battery was disconnected !
Note: Ensure that a SmartKey is available to disarm the system when reconnecting the battery. Either press the unlock button on the transmitter, or press the START/STOP button.


Battery Charging and Maintenance

If you use your XK daily for long drives, ignore this section. However, most of us use these vehicle somewhat intermittently...

First, always lock the car - even in the garage. Apart from being more secure, the onboard computer will shut down all systems after 6 minutes. If left unlocked, it takes 36 mins before it will shut down all the systems. Since these cars use SmartKeys, keep those well away from the car to keep it locked.

Jaguar has provided 'jump start' battery charging posts in the trunk.
The Positive one is in a compartment on the left hand side, behind a ribbed cover, as shown in two of the photos.
The Negative one is a bare stud under the trunk floor, next to the spare tire, as shown in another photo.

However, I only recommend using these terminals for jump starting or emergency battery charging.

To prevent future problems, use a low power battery charger. aka 'Battery Maintainer' 'Trickle Charger' or, to be really fancy, 'Battery Conditioner'.

Jaguar sell one for $100+ but Richzak has discovered that it is actually a CTek 3300, and about $20-25 less, and highly recommends it. As do several other Forum members - it gets good reviews.
It is also rebranded and sold by Porsche and Aston Martin for even more money.....

I use a Chargemaster 365 with good results, but several forum members have had mixed results with Battery Tender (Jr and Sr models).
Other members have used a BatteryMinder, and even a Solar Panel.

The auxiliary power socket (what was called the Cigar Lighter socket back in the non-PC days) is not live when the systems are shut down, so can't be used for charging.
I recommend connecting a battery charge lead directly to the existing threaded studs on the battery leads. I used a Battery Tender Ring Terminal harness with fused plug
(Amazon Battery Tender 081-0069-6 Ring Terminal Harness with Black Fused 2-Pin Quick Disconnect Plug) together with a Battery Tender 25ft extension cable (also available in 12.5 ft length)
(Amazon Battery Tender 081-0148-25 25' Quick Disconnect Extension Cable).

The Ring terminal harness attaches to the threaded studs on the battery leads with 2 * M8 (metric 8mm) nuts. It has a 7.5A in-line fuse and about 2ft of wire.

It plugs into the 12.5/25ft extension, and that easily reaches my charger. The cord easily passes under the weatherseal of a closed trunk, as shown in
the photo of the grey XK Portfolio. I keep the excess wire coiled in the spare wheel well.

Ensure the connector is insulated or covered when not in use, and this lead MUST be fused (and as close the battery as possible), since it is live at all times, and bypasses all the car systems....

I plug my maintainer in overnight, once a week or so, but some member (like Richzak and Stuart S) leave theirs plugged-in all the time.

And a final note: the Owners Manual specifically states to remove the battery before charging - probably because of the risk of outgassing of hydrogen from the battery and also the possibility of electrical surges.
Many of us have been using good-quality low-current chargers for years without any problems, but I would follow the Factory recommendation if you need to use a high-current (25+ Amps), or 'boost' charger. Actually, I'd try to avoid using boost chargers altogether - they tend to shorten the battery life.

 

If you connect a Hot Box to the battery terminals before you remove them from the battery you shouldn't have to reset anything. Plus it keeps the ECU powered up.

Great info though.

 

What if you connect your battery charger (maintainer) to the remote battery terminals in the trunk before you remove the old battery? Will that also work so you don't have to reset anything?

I think the answer is yes, because I suspect the remote terminals go to their respective POS and NEG terminals in the trunk on order to charge the battery. Am I right?

 

Stuart:

I am not sure that the battery charger (maintainer) alone will work, as it does not carry a 12+ volt supply to the car. The car battery usually provides about 14.3 volts while the chargers merely supply a trickle to maintain the battery. The chargers like yours or the CTEK does not provide enough juice alone to handle the load the car requires.

A fully charged spare battery or hot box clipped to the main battery terminals would supply enough voltage to allow one to switch out an old or defective battery without losing any of the components and thus eliminating the requirment of a reset or reprogramming.

Any other input on this topic?

 

sam's club sells a 49AGM duracell battery for $159.99, I don't think it has a vent connection. Does AGM battery really need venting or are we just being overly cautious? Thanks for a great summary post!

 

Jeremy,
Thanks for an excellent post and for the Lucas quote. LOL

 

i will again ask, the AGM battery from duracell and diehard 49 do not have vents, I dont think that these batteries without liquid need vented, am I corrrect or way off line?

 

I would strongly recommend that you DO NOT DO THIS. Battery chargers do not put out a smooth stead 12 or 13 volts, they are a noisy (electrically speaking) output with AC ripple voltage on it. Your car will not thanks you for this, it may actually damage some components.

When the battery is connected, it absorbs those ripples and limits the voltage spikes from the charger.

I have used a 12 volt battery from a motorcycle or a backup battery from an alarm system.

 

I stand corrected, the agm duracell from sam's does have two small vent holes. the vent tube from oem jag battery fits the hole. Does the other hole need to be plugged?

 

My suggestion: to be 100% safe, plug it, to ensure any hydrogen being released is directed out of the car rather than building up in the enclosed space. However, the chance of an explosion is pretty remote.

 

Hmmm... do these battery maintainers work well for AGM batteries?

 

We have different model CTEK's here compared to the US and mine has a specific setting for AGM's.

The CTEK 3300 seems to suggest you use the cold weather setting on those for AGM ones so there must be a difference in the batteries.

Whilst on the subject, I wonder why Jaguar issued a Technical Bulletin saying that you should only replace like with like batteries, i.e. replace AGM with AGM and flooded type with flooded type.

 

I think one reason could be that cars originally equipped with flooded batteries use a different alternator/voltage regulator than cars originally equipped with AGM. AGM batteries are sensitive to being overcharged, and an alternator designed for a flooded battery might overcharge an AGM.

From BatteryUniversity.com: "Automotive charging systems for flooded lead acid often have a fixed float voltage setting of 14.40V (2.40V/cell), and a direct replacement with a sealed unit (AGM) could spell trouble by exposing the battery to undue overcharge on a long drive." See: Absorbent Glass Mat (AGM) Battery Information - Battery University

So does that mean you should change your alternator if you switch to AGM? I'm not sure. Perhaps someone on this forum can give us a definitive answer.

Stuart

 

Multiple posts on this site have replaced flooded battery with agm and so far have not seen anybody with a problem occuring. I doubt that anybody has replaced the alternator! For people who have replaced with agm, wondering how long you have had your new batteries? Any problems arise?

 

I put an Odyssey AGM battery in my XK8 about 3 years ago - no changes made to the electrical system or voltage regulation, but i had no problems with it.

 

Thanks for the instructions. With my XKR Convertible (10/2007) it was slightly different. It was not possible to slide out the battery because there is a metal bar in front of the battery (picture in the middle). I had to remove the mounting on the right side of the battery (left picture). Thus I could lift the battery which is necessary to get it over the metal bar (right picture without mounting on the right).

 

It looks like you didn't remove the front clamp:

 

Do we need an antitheft radio code? Instructions in the manual says to be certain to note radio "codekey" but whatl is a codekey? If I have to have a code to reactivate the audio, it is something I would like to confirm I have first.

 

Not on US market XKs.

 

Every module in the XK is security-coded to the car anyway, so they don't need an anti-theft system - the audio module will only work in another car if you use the Jag diagnostic system to authenticate it.