There ya go!

There was no way I was gonna pay well over $100 for a battery. SOME things are worth spending money on, but I believe an $88 battery will be just fine for these cars. Now, mind you, I have NO intention of keeping ANY battery over 3 years old in a cantankerous car like the XF.

And I'm not picking on the XF. We (at work) learned the same lesson with my company Durango (which I am happy to report is GONE now)... it would crank over, and start, but as soon as you let go of the key, it died.
$90 tow bill and one ($70) hour of labor later, they got it running - by replacing the battery.

I'd never heard of a battery that was strong enough to turn the engine over being the reason a car would not start. Seems the ECM/PCM/etc. was seeing something it didn't like.

So for me, I'm going with a cheaper batttery (that meets the specs of the car) and replacing it every three years to avoid being stranded.