New battery in GTI, battery drain issue. (Flat after two days)

[Dipesh2031]

Hi,

I have a new (2-3 months old) Varta silver battery in my gti type 096, (accidently bought a bigger one for a diesel golf oops) I've noticed my car will not start, the driver info screen goes blank. battery is flat, I wonder what is causing this? I've heard of RNS battery drain but thats when it's retro fitted to the mk5's? whats going on 

[joe6]

Is the alternator charging properly? That would be my first check. With the engine running you should get about 14.5v across the battery terminals. Leaving interior lights on or boot not securely shut (light on) can also flatten the battery overnight. Has any additional wiring been added to normal spec, that would be my next check to see if there is a drain. Not sure what else to suggest.

[Dipesh2031]

Thanks! I didn't know where to begin