Why won't my Droid Ultra turn on?

[AC Question]

why wont my droid ultra turn on?

so recently my black droid ultra battery died. when i plug the phone in to a charger it constantly starts up (showing a white Motorola logo) and shuts off. i have tried holding the power and volume down key to reboot and even factory reset the phone and it goes back to the constant on and off. i also got a solid green LED light. any help would be greatly appreciated! thank you!