2 days ago the XF started kinda slow and the wing popped up. I drove around for about an hour with no problems. I jumped in it today and there was nothing. Absolutely nothing. No sound, no display, no clock. It was completely 100% dead.

The battery is just under 1 year old. It either is defective and shorting itself out, or there's a circuit somewhere drawing energy.

Update (yes it's taking 2 days to write this post) I had it on trickle charge while still in the car and it was still completely dead. I took it out to NAPA and their tester couldn't tell if it was good or not. It's currently at NAPA on their charger til 4pm. The brand name on the battery is "Werker".

What the H is going on with this?

 

If NAPA cant tell you if it is good or bad, I would worry about the test equipment or the tester. You could have one or more bad cells and it is just no good. Stuff happens. At a year old you should get some help on the replacement cost.

 

To test a battery it has to be charged up, if it does not charge properly then it is bad, if it takes a charge but fails the load test it is bad.
You cannot test a flat battery.

 

I'm off to NAPA. It's been charging there for 5 hours. I actually hope it's bad as it would be cheaper than tracking down some stupid electrical issue on the car.

 

The battery's toast. NAPA wants $97 and Advance wants $155. Goin with NAPA. The battery will be in Monday.
I can't do the warranty because I bought it from a localized company in MN.

 

Wow! What a difference in price. Even our batteries are expensive. Did you check out good old WalMart?

 

AFAIC, if it comes in under $100, I'm happy. NAPA has an 18 month 100% warranty then pro-rated after that. It's good enough. Bummer they didn't have it in stock though.