Over the past 4 days the charge on my ZMAX PRO has lasted maybe 4 hours MAX.  It would charge very slow if at all and would sometimes discharge while plugged in. As of last night it would not charge past 10%. I powered it off and it charged to about 60% but it has been unplugged for less than 2 hours an is already on 20%. Is there anything that can be done about this or is it time for a new phone since the battery in this phone is not replaceable by users?