i bought 2 650 mah ego t batteries a few months ago but didnt start using them till about a month ago on a vivi nova and im noticing that one battery dies about an hour after a full charge while the other last about 6 or 8. Both are identical other than one says (insert store initials here) on the end...which is the battery that last longer and the crap battery is blank. The previous batteries i got from them before from a starter kit both had store initials on the end and lasted me a long time on a charge and eventually lasted almost 18 months before dying off. Coincidence????