Most F-Types have a pretty weak charging cycle. If you don’t drive long distances, the battery fades and will eventually die from chronic operation in a low voltage state. The answer at that point is a new battery. But… many new batteries sit on the shelf for a while, so they too may be in a pretty low charge state when installed. In most cars, that would get remedied upon the first solid drive, but in the F-Type, a partially charged new battery can fall into the same low voltage rut.
The problem is exacerbated by Jag’s selection of a high quality AGM style battery, which operates at a little higher voltage than Lead Acid. AGM’s are notoriously very finicky to slow-charge once significantly depleted, and even if new condition, they may fail to accept a low amperage charge.
Obviously this isn’t a great dynamic for the Jag’s low amp charging circuitry. So it is important to fully charge a new AGM battery upon Jag installation–your dealer probably did not do that because, sadly, they really don’t know much about F-Types.
Recommendation: disconnect your new battery from the car and charge it manually to 100%. After that it will likely function just fine. The owners manual recommends physically removing the battery from the car before charging it out of an abundance of caution.
You will need an AGM capable charger that outputs at least 5A to get your new battery back up to 100%. You will probably find that 3A or less “hangs” during charging and the terminals may get a bit hot. The solution is to apply 5A to10A to an AGM in the 1000 CCA range, like ours. It is worth investing in a decent charger with a percent-charge readout, so you can verify and monitor AGM progress to 100%.
Good luck! I think your F-Type + AGM is displaying normal behavior.