The Mégane II Owners' Club

Hi, I have a 1.6 Megane cc (2007) and think the battery needs replacing (hoping its just battery). Whats the correct battery for this model as when I try a search I get the option of many stating different Capacity (ah) and Cold Crank Amps. Havent had the car that long so don't want to swap it with similar to whats on just in case its wrong to start with, cheers