This link will take you to the X150 page which is where you want to be.

https://www.jaguarforums.com/forum/xk-xkr-x150-33/

Start a new thread appears as a little radio button on the left both above and below all of the threads. That said, no need to post there for this topic as the advice is the same. Your battery is toast. bring it to the auto parts store and they'll load test it for free but you should just replace the thing.

 

So here is a successful update through this morning and this afternoon.

From the manual I followed the instructions to place the Smart Key in the docking station in the console. This was to deactivate both the lights and the horn alarm from opening the trunk lid with the manual valet key. Even though the battery was dead the alarm was active as soon as the CTEK was connected. Having success with that I plugged in my CTEK battery maintainer.

I chose not to boost the battery with jumper cables from my other car based on forum member comments and elected to use the CTEK.

Being patient from about 9am to about 1pm today with the CTEK did its job. I checked the battery output with a voltage meter to just above 12V. I opened the door foot on the brake and pushed the starter button. INSTANT START, amen!! Checked the battery output at 14.9V on start up with the engine running. Reset parking brake, reset windows, radio OK, turned car off as instructed in the manual to remove the Smart Key from the docking station. All systems go for a nice drive. Sought out the nearest highway and travelled 30+ miles. Exhilarating to say the least. Flawless all systems fine.

Lesson learned, even in the summer when not using the car often, lock the car even though it is garage kept to limit any potential draw down on the battery and let the CTEK to the job it was designed to do - maintain the battery.

Interesting and frustrating even the dealer service advisor did not instruct me to dock the smart key to disable the alarm first before connecting the CTEK. Advised me to disconnect both the positive and negative terminals from the battery, wait 30 minutes and reconnect them. This did absolutely nothing.

Thanks forum members for caring and your help.

Cat2