I have a recurring issue with a current leak on my 2010 XK (X150) convertible. I have had to replace the battery twice in 18 months despite routinely keeping the battery on a tender. I also religiously put on the parking brake before turning off the car, and use the lock button in the door handle to lock the car and put it in sleep mode the fastest. I have read that there is a quiescent current monitoring system designed to protect the car from such batter drain issues, but either my car does not have it or it does not work as advertised.

I have used ChatGPT, Google Gemini, and other AIs to suggest likely culprits, and the rechargeable backup battery inside the alarm siren appears to be the most common one. Unfortunately, the fuse box that was supposed to house this fuse was reported to be in a fuse box that does not seem to exist on my 2010. After additional querying, it appears that there may have been multiple different locations for the fuse in question during the production run of the 2010 base XK (X150) convertible, some of which were reported to have been hidden behind trunk carpet without any access panel or flap. The owners manual refers only to three fuse panels, but none contain the fuse for the rechargeable backup battery inside the alarm siren.

1) Does anyone have or know of anything definitive on electrical system changes during the 2010 XK Convertible model year production that could explain the different fuse box locations?
2) Does anyone else have a 2010 XK convertible with recurring, excessive parasite drains on the battery? If so, were you able to resolve the issue?
3) Does anyone have any recommendations on higher likelihood culprits to check before going through every fuse in the car?
4) Any other recommendations?

Frustrated,

Ted Bellinger
2010 Jaguar XK (X150) Convertible

 

I do not have the Electrical Guide for your MY.
Do you have the workshop manual?

 

https://drive.google.com/file/d/16x2...ew?usp=sharing,
https://drive.google.com/file/d/194o...ew?usp=sharing,
https://drive.google.com/file/d/1A1F...ew?usp=sharing,
https://drive.google.com/file/d/1hu7...ew?usp=sharing,
https://drive.google.com/file/d/1i9E...ew?usp=sharing

You can access these until I remove that access in a few days.
I don't remember which is which though.

 

Days later, access removed.

 

Bugger. I waited too long.
Wanted to toss them in my laptop.

 

I seem to remember that the power source for the alarm siren that you are looking for is direct from the under bonnet fuse box and not via a removable fuse.

You can unplug the siren for a period to see if that is causing your battery drain