something is draining the battery on my 2005 xc90. If the car sits a day or 2 it will not start. I replaced the battery and thought I had the problem solved, I was wrong. The problem is more prevalent in the cold weather. Nothing more annoying then going out to start the car and its dead.

 

next step is to use a meter to measure the current draw to the battery with the engine off. Start pulling fuses until you see the current draw drop, then research what's on that circuit. Typical causes are things like vanity lights / glove box lights that are not switching off so I'd start by taking a look around. A small light can drain a battery in two days.