Alster370, I don't see anything in this thread that indicates you have changed the battery, so am I correct that you still have the battery that was in the car when you bought it? If so, seems to me the cheapest solution is to buy a new onw.

 

Probably is the cheapest solution, although then I'd have to pay for it rather than the dealer. I just don't want to swap the battery only to find it was a faulty module causing the drain. Can the battery be swapped without dealer reset?

 

Yes

 

Update on Battery,

Took the XKR to KwikFit this morning for a free battery check. The guy checked it twice with some Bosch tool that prints out a receipt from each testing. I had the car on trickle 24/7 since the incident, so the battery should be nice and full, and when I unplugged it to set off it was on stage 7, which I believe is maintain. Results:

First Test:
Voltage 11.94V (Im assuming this was under load)
Rating 800 SAE(A)
Measured 508 SAE(A)
Battery Health 4/14
Overview: Good, Recharge

2nd Test:
Voltage 11.88V
Start Capacity 49%
Overview: Good, Recharge

In my opinion, 4/14 for battery health doesn't constitute a healthy battery, you might get away with it on a basic small engine car, but it aint gonna cut it on a V8 with lots of electric heaters. Sent the results to the dealer, dont think he can really argue it doesn't need a new battery.

 

Thing is though, if it was fully charge with a REAL charger it may be a 12/14. That 4/14 I'd think meant Current State, as still discharged. Course if the dealer would give you a new battery, I'd be all for that. Gratis, of course.

 

I'm by no means a battery expert, but I think they need to show more than 12V to be considered healthy.

These modern cars with the loads of computers and the extreme requirements of the electrical systems do not seem to play well with each other when the battery is weak. At ten years old, I really don't think there's any room for disagreeing that the battery needs to be replaced.

I understand that the OP would prefer that the dealer (I presume the selling dealer, with some kind of limited warranty) pay for this item, but at some point isn't your time and frustration worth it to just get a new battery and move on with it all?

 

Whatever the dealer offers it will get a new battery, like you say, batteries aren't long life things, especially on a car like this.

 

The 18month old battery in my 13 XKR vet spends its idle time on a CTek 5000 and the battery reads 12.3V at rest.