Main Fuse for Battery?
 

Something is draining my battery on my X5. I think the battery is totally drained right now (still need to check with voltmeter). I may have left one of the reading lights on. Wondering - is there a way to disconnect the entire electrical system via a master fuse of some kind to allow the battery to charge fully from the trickle charger? Also this would be useful if the car is going to sit for a long time.

Otherwise I am looking into getting one of those remote controlled battery brain modules to make quick disconnect easier. I live in the city and don't drive my car much but I hate it when I need to leave for a trip and the battery is dead and end up having to jump it.

The X5 electrical system is more sophisticated than that. There is a sleep mode which uses less power than the vehicle not being in sleep mode, and the vehicle goes into that some time after shut down, as long as all conditions are met. If there are any small current draws still on, they function like a trigger and they will prevent the vehicle from going into sleep mode. The resultant power drain is far larger than the draw of just the trigger, resulting in a flat battery.

Problems with residual current draws need to be tracked down with an ammeter.

If your vehicle is being left to sit for extended periods of time, many have found that a smart battery tender, instead of just a trickle charger, is a good investment. BMW even sell them.

Hmm that would be great except my X lives in a parking garage and it's a bitch (and unsightly) to run an extension cord. I might just break down and get the battery brain :-/

Sucks because i just have one of those $3 ebay power cutoff wheels for my Z and it works great. Obviously that wont work very well on the X with the battery being buried.

So a one of the overhead lights was left on which normally wouldnt be a problem buy my trickle charger shit the bad so I just bought one of these:

Super price on Schumacher PSC-12500A at ToolTopia.com