Main Fuse for Battery?

[we350z]

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.