That is precisely why I started this thread.

 

The picture of your OEM battery appears to be an H8. Funny thread.

 

If it helps, I bought an interstate MTP-49/H8 for my 08 XK ​​​exactly 5 years ago, it fit fine and has been trouble free since. Always hooked up to a C-tek immediately after parked for the day.

 

Thanks. I see that my local Costco has that same AGM battery for only $169.

 

AAA will come to your car and install the battery. I don't know if you can specifically request a T8 group battery.

 

I did try AAA. My car is bricked in my garage, and they wanted to “ drag” it out, to install the battery. I said no.

 

I also 'tried' AAA, for 14 years...when I finally needed a tow at 7:30 one evening it never arrived. No communication that they couldn't find a hauler after 5pm in my semi rural area. So, my false sense of of security cost me a couple of grand. No more AAA for me.
Sorry I got off subject!
I was working on my 08 xk yesterday, noticed that voltage was dropping rather quickly ( one door open, ignition nm off). I doubt the illumination bulbs are drawing much so are the subsystems simply drawing this battery down while waiting to be asked to do something?

 

Yup. You open the door, the car enters ‘convenience mode’, awaiting your orders sir!

 

it at times does not feel like a convenience to constantly be concerned @ the battery!

 

Thanks for all the guidance regarding the correct battery. I put the Interstate AGM H8/49 in today. Although my seat, and stereo functions will need to be reset, everything works as it should.

 

I believe the MTP- 49/H8 is a non AGM battery.

 

Battery has this on the side “Interstate AGM H8/49 “.
Plus, no place for a vent tube.

 

Interesting. I'm pricing batteries right now, and the AAA battery quote generator came up empty for the 2009 XKR. I wonder if they even had the right battery...

 

Makes sense, H8/49 likely just the size/fit.
Thought that you got the exact battery (MTP).

 

AAA in SoCal doesn't carry a battery for the X150. Ask me how I know. If you want somebody to come out and install an AGM battery try these people: battery.com or 800-battery.com. They are not cheap but they do the job in your driveway or in your garage. The batteries in these cars are in the boot, so if your xk is pulled in nose first in the garage that should not be an issue. The battery I got from them is a Diehard Platinum H8-AGM. Make sure that the battery you get from whomever is fully charged when installed. Good luck.