Just got my civic si on wednesday and I have had two events where I had a dead battery.
-The morning after I bought the car, I was sitting in the driveway and I plugged in my laptop adapter and within 10 seconds the battery died. I figured the battery mustive been low from someone messing with the radio/lights or something.
-Last night I accidently left my lights on when I ran into a store to buy something fast. Exactly 27 minutes later (thanks to the parking meter) I tried to start the car and the battery was dead.
The car is a 2007 Civic Si and it's the factory battery that came with the car. I left my headlights on in my garage on purpose and it pretty much takes exactly 30 minutes for the battery to die out.
Is the battery dying or is that normal? My dad said it's normal and maybe it's a little old. I don't know though. I plugged in my laptop for 10 seconds (it barely had time to get to the windows logo before the battery died).