ZTE zmax pro won't hold charge

[AC Question]

Hello android central today my digitizer arrived so I changed it,took phone completely apart even battery. I put phone to charge and turned it on, battery started to charge but pretty fast.. I thought weird but cool my phones back..Yay... I unplugged it and it turned off.. tried charging again and the percentage restarted from 1% it charged to 80% I unplugged and you guessed it... IT DIES... so basically can some one help me please. I will be opening it up again tomorrow and trying to fix it.. will update if I find a solution... thanks and goodnight...lol