Ok, so my Ctek arrived today as well as the addons I purchased.
Watched the LifeOnCars video where he hardwired his, but did a modified version in the boot instead of directly on the battery.
Read some comments that direct to the battery bypasses a sensor or something.

Couple of notes:
The Ctek MXS 5.0 comes with alligator clips and 7/16" eyelets.
The connectors in the boot/trunk are 3/8". A 7/16" is a hair too large and won't make great contact.
I added the 8 foot "comfort clip" extension, so I could mount it on the wall and whether I pull in or back in, it will reach.
The LifeOnCars dude said he had to trigger the boot latch to turn off the lights.
With my convertible, the lights go off after a couple minutes, so no concerns leaving the boot ajar.
Also, with the 3/8" eyelet kit, the pos and neg leads are split. This was perfect and I was able to feed it through the plastic cover vent.
(Photo below)
All in was around $125 plus tax.


10mm ground, 1/2" socket Pos under little boot.


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Look at how nicely it feeds through the vent and caps off when not in use.



Wall mount mid-way.

Hope this helps someone someday!

 

I drove out of my garage once forgetting to disconnect. That tore the wires apart at the boot seal. I'd suggest to avoid possible damage to have a pull-connect somewhere between the CTEK and the boot seal. I also did the same thing with my motor home once upon a time.

 

There are many different ways to connect your battery maintainer. Just search this Forum.

* A WORD OF CAUTION *
It's important to note that beginning with the 5.0L models (2010-2015), the factory included a Battery Monitoring System Module attached to the negative battery terminal. It's basically a device that controls the voltage regulator to maximize battery life. If you attach the negative pigtail of your maintainer (or anything else) to the negative battery terminal you can fry that BMS Module. Find a chassis ground for that negative pigtail; don't attach it to the negative battery terminal.

 

Something to keep in the back of your mind, is that if you get random error lamp indications on your Ctek, it could be due to the extension. The Ctek wires are 18-AWG. I was using the Ctek connector to SAE pigtail and then to a 15 foot 18-AWG SAE cable to the car, and was getting an error if the battery was even slightly discharged. Went round and round with Ctek support to identify the issue (as I never had any issues with my Deltran Battery Tender brand maintainers).
I finally figured the Ctek is more sensitive to the extra resistance of the longer extension. I switched to a 10-AWG SAE extension, and have not had the charging error return.

 

I use the Ctek extension & get these random errors, so thanks for that its' nice to know why.

 

My car came with one hardwired..

They drilled a hole in the bottom of the plastic trunk..
Pull the cord through it and use a heavy duty extension cord

Trunk stays closed

No issues.

 

Is that so?!? I've had a maintainer directly attached to the battery terminals for close to a year now on my 5.0. Either I've been lucky or the maintainer has been gentle.

 

No need to drill any holes, just close lid on wires & they're not trapped at all. In fact the rubber doesn't appear to seal at all as the wires slide around easily, was the same on my previous '07 XKR.

 

@Circumnavigator , your Model Year of the XKR does not utilize a Battery Monitoring System. There is no need to worry about connecting directly to the battery, no system is being ignored, with possible exception of the Battery Junction Box.
Incidentally, the Jump Start Post IS behind the Battery Junction Box.
Of course, should you connect your charger behind the box, and a fuse is blown, there will be no charging.

 

There are many inaccurate rumours about the BMS.

 

How do you know that your BMS Module is working? You don't, because your CTEK is always in use, your battery stays fully charged even if your BMS Module is damaged and not working properly.

See Post #24: https://www.jaguarforums.com/forum/x...-241034/page2/

 

Ok, sounds like running the negative to a ground somewhere will help, as the BMS may not understand the charge of the battery due to the maintainer. I don't remember seeing any DTCs in the scanner for the BMS recently so I'll work off the hopeful assumption that it's ok. Without understanding much of that system, I would be surprised if it would kill the unit by running current through. Maybe just throw off the state of charge logged for a bit?

 

I tried hardwiring my CTEK exactly the same way, but when I tried to back the nut off the positive terminal, the whole thing turned. Did you put vise grips or something on the base to keep it from turning?

 

IIRC, I didn’t remove the existing nut, just put the eyelet on the post, and added a nut on top. (Could be wrong, but seems like that’s what I did.)