I just happened on a 2008 XKR Porfolio convertible recently and am totally taken with the car. As many people report, there are numerous electrical gremlins that have been greatly reduced by locking the car every time I stop and putting a battery tender on it overnight. Here is my question. I would like to power down the nav system, the CD player and the Bluetooth device. I don’t use any of them and would think that would reduce the load. My question is whether the rest of the system would continue to operate. My simplistic notion was just to remove the power cables from each device. Would this work? Thanks.
I doubt it will make a noticeable difference. When you shut down the vehicle, over a period of some hours, the quiescent current drawn from the battery drops down in stages to a few tens of milliamps. In the case of my '97 XK8 the final figure reached is 32mA once all the modules have entered sleep mode. There was hardly any difference whether the car was locked or not. Most of this current is supplying the Security and Locking Module and the alarm system when armed
At this figure, a 90 or 100AH battery in good condition will supply the standing current for a few weeks and still leave enough in the battery to start the car without issues.
If you want to go to the bother of hooking up an intelligent battery conditioner you could leave the car for as long as you want and all should be OK the next time you use it. The amount of current that is being supplied to preserve memories in the radio etc. is so small as to be not worth the effort of disconnecting them in my opinion.
Eric
Shropshire, UK