All my batteries Joye 510, joye 510 mega, and Egos are doing just fine and I've been vaping for 3 months. Haven't lost one yet. Charge life depends upon the battery itself. 510's usually last between 1-2 hours. 510 megas usually last between 3-4 hours. Ego's 6 or more hours. All those times vary greatly depending upon how much vaping I'm doing in that time frame. Example being I started using my Ego battery(650 mah) this morning at about 8 am and its still working just fine 9 hours later but I was at work all day and only vaped occasionally. So my 6 hours timeframe is based upon being home and vaping often.