Hey all!
So I just purchased the CTEK multi us 3300 and just instead it.

Put the positive on the battery and the negative into the chassis where the battery is grounding as well.

I left the charger over night but the charger still says charging. From what I understand this process should take 3-4 hours.

My battery also seems perfectly fine as it starts a car that was sitting for 3-4 days without any hesitation.
The manual says for AGM batteries, which I believe the XF is that j should switch to the winter mode but have not seen any other people on the forms do this. Any suggestions?
Need to have this going as I leave town for 2 months tomorrow!
Thanks in advanced!

 

The older XF, 2008 to 2012, came with an ordinary flooded cell lead/acid battery from the factory, and it was only from 2013 onwards with the stop/start system they came with AGM batteries. Although it is possible that someone has replaced your original battery with an AGM one. AGM is still lead/acid, not gel.
Have a good look at your battery to figure out what type it is then set the CTEK accordingly.