For newer generation cars, their electronics will keep running and depleting the battery power. It is very likely your battery will be flat within 2 weeks and will need to jump start. Just make sure you are subscribed to AAM and they will despatch someone to jump start your car FOC in a jiffy. If your battery is more than 18 months old, it will probably KO and if it does, AAM will change a new one (at selling price). So nothing to worry, go and enjoy your holiday with a piece of mind. Cheers.