Battery loses charge after being parked overnight. Why?
I have a 2002 VW Passat 4motion. After driving 1000km across Europe the battery lost charge on the 7 hour ferry crossing meaning I had to have assistance to start the car. I drove the car for about 30 minutes and after parking it for 2 hours, it started fine, however, the following day after being parked overnight, the same problem happened again. what is causing this and will a new battery solve the issuer? Thank you