I see a lot of battery related issues in the Jag forums, I am curious if anyone has tried switching to a Lithium battery? They hold their charge longer, higher CCA, put out higher amps for longer and most importantly charge faster. From what I have read the AGM batteries don't charge fast enough for our Jag's charging system causing chronic low voltage and that creates more issues. Lead acid go out often and can't go below 50% without damaging them and have more problems in general, it seems a good hi-amp alternator and Lithium battery would solve all of our issues with low voltage for good and they are lighter to boot. I changed my battery once and almost blew an artery trying to put that thing in a tiny space in the trunk. It went out a year later, no fault of the car I had it on a trickle charger that was highly rated. They have longer warranties and rated to last 3X longer than lead acid. They are not that much more expensive either anymore on Amazon.

 

Check out Unhingd on the F-Type forum, he put a lithium battery in his F-Type years ago and it has been trouble free since.