I had mine checked for the same reasons when I had my last oil change. They said it's normal for it to say that without the engine being started. If it comes on while the engine is running, then you need to have it checked. Here's my guess why. The alternator charges the battery while the engine is running. If the engine's not running, then the alternator isn't charging. So the warning comes up when the car's not running. It makes sense to me but I'm not a mechanic.