binxta350

Hi all hope someone can help.I've had a problem with my battery going flat(just the once)had the alternater checked and its fine,found the problem it was my cd changer.The battery has been ok since,but I'm about to go away working for 12 days,Is it adviseable to get a new one because of it standing for so long or can I just disconect it?what about the ECU will it cause any thing to go wrong with it?