The Moto G ships with a micro-USB cable, that can be used to charge it by plugging it into a computer. I took the Moto G on a trip recently where I only had access to a Windows 8.1 notebook. I did not use Moto G for a few days and it completely drained out the battery. On plugging the dead Moto G into the notebook for charging, the LED on the phone would blink for a few seconds and the phone would go dead.
No matter how many times I tried this and how long I left it plugged into the notebook it would not charge! The Moto G had been charged with this same notebook successfully when it had not been fully drained. Folks on the Internet suggested holding the power button pressed for 17 seconds or freezing the phone for a few minutes in the refrigerator. None of these methods worked for me.
I noticed that there was some type of communication happening between the Windows OS and the Moto G whenever I plugged it in. I guessed that this was what was causing Moto G to not charge from the notebook. Once I was back from the trip I found an old micro-USB charger from Samsung that could be plugged into the electricity outlet. Moto G started charging successfully from this! 🙂