Re: Battery is draining while its plugged on for charging
I see this problem all the time with bad cables. They flex enough times, or get dropped, then eventually will show up as slow charging, or charging, but battery percentage keeps dropping. Definitely check that first. Battery percentage can also drop if connected to a charger not powerful enough to charge your phone, but I'm assuming you're using the OEM charger here?
[Thread moved to Moto G subforum.]