Based on the info from V2, you have to send it back to its original country for warranty claim.
You can still do repairs on local LG stores, but you kene bayar la.
It's suggested to do repairs locally rather than sending it back because its gonna cost more.

My usage:

1) Facebook
2) Clash of Clan
3) Browsing using Opera
4) viewing instagram
5) pick up 3/4 call in office hour.

Unplugged at 6.30am. and drive to office for 20min. arrive at office, the battery still indicate 100%. after 1 hour just lost 1%.With my nexus4, after driving for 20min, i lost 2% of battery.

In lunch hour, with nexus4 i already lost 50%. Nexus is far more better, losing 20% of battery. Can see the significant different between nexus 5 and nexus 4.

at the end of the day, my nexus 5 still indicate 50% of battery left. if nexus4, only 20% left. i'm using stock kernel for both nexus.

oh hell no....
that's made a lot of user disappointed man...

Other than above your usage almost similar to mine, but your Nexus 4 battery dropping almost 99% identical to mine... at the end of the day left 20% battery as well or even worst. Somemore, I even Greenify my apps like, Facebook/Foursquare/Instagram and some other often push notification apps as well.

yeap... kinda sympathy to LG sales also...

haih anyway....

That is why use Greenify to block it from wake up. Tried Friendcaster, don't like the interface much.. Tried Flipster, like the interface indentical to Offical FB apps but still lack of certain feature.
Lol? You must be Facebook a lot. Have you use Greenify and mange your wakelock wisely?