I witnessed a common and very annoying problem with really expensive cars. Often, someone who has a high-line car also has a preference for high tech. I was once the unfortunate stablekeeper for a Porsche 928 S4 that had front and rear in-dash radar detectors, a woofer in addition to the stock twelve speaker system, two cell phones, a police scanner, an accelerometer, and a whole bunch of other shit, all installed aftermarket.
The vehicle could sulfate an oversized Interstate battery in four days, just sitting in the parking lot. Since the battery is located in the trunk, under the woofer and all that other crap, I was less than enthused about this car’s habit. Try changing a battery in a plush white carpeted trunk without getting it dirty–it’s not easy or fun.
I figured the problem was “leakage” from all those gadgets. Aftermarket installers almost invariably wire electronic devices straight off the battery. So I made a removable cap that I could use to disconnect the toys while the car wasn’t in use.
That worked for about two weeks, then it died again. It turned out that this three hundred horsepower monster already had such a large electrical demand on it that its alternator could not keep up with the battery drainage even when the vehicle was driven well above highway speeds for hours at a time (woo hoo! That was the best “test” I ever performed!). Solution: yank all the shit.
So the moral of the story is if you’re going to have a bunch of trinkets added to your car, find someone really, really good to do it for you. I don’t know that guy.