Stupidly whilst working on the 2012 XF I disconnected the battery earth strap and closed the boot. In addition I don't have a key to manually open the boot.
Could I connect a small 12v battery to the alternator in the bonnet and feed some power in?
I can access the interior, so may be able access from ther.
Any advice would be welcome

 

Will this thread help?

https://www.jaguarforums.com/forum/x...nal-xf-159374/

 

Without any battery connection you don't have a complete circuit anymore? I don't think applying 12 VDC will work because of this?
Which means you need to pull the emergency release cable somehow that's inside the trunk?
I don't remember if your car has folding rear seats or not? Of course the release cables will be in the trunk too if you do so no help there?

Anyway you can get a key? Might be the simplest way to go.
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Applying 12v will work just fine. Connect a battery between the starter big connection and chassis.

 

The simplest way to get power on to the car is via the front fusebox/CJB. It can be a little awkward attaching a clamp to the positive terminal but is not hard and the door "check strap" bolt - not the strap itself - is ideal as an earth point for the negative clamp. Open the fusebox hatch near the accelerator pedal and look inside or feel for the rubber cover near the top of the fusebox assembly. (one can see it immediately above the fuses in the attached image). This can be pushed aside to expose the nut which secures the thick power supply cable to the fusebox and attach the positive or red clamp. There is no exposed metal anywhere near so there is very little chance of shorting anything out. Attach the black or negative clamp to the bolt on the door check strap and finally attach the leads to the battery or power source making sure you get the polarity right..

Dont try to use this to jump start the car but press the boot release button with your nose if need be and the boot will open. You could have someone else press the button on the boot or press the button on the remote.

Thats it - job done. Now you can access the battery to jump start or charge or remove.

 

Pretty much every time this question is raised , you reply with this same misinformation, despite many users , myself included, doing our best to educate you : "Without any battery connection you don't have a complete circuit anymore... I don't think applying 12 VDC will work because of this"
. Is that really being helpful ? I'm not trying to be nasty, I just don't understand your continued belief in that comment !!! cheers

 

Well said. Total garbage.