I have a 5v box mod from madvapes using Ultrafire 14500 batteries and last night it quit working. I checked the voltage on the batteries, 1 was @ 3.2v BUT the on other one I could not get a reading, 0v. I checked 3 times and it always read 0v. I put them on the charger and 1 hr later they both read 3.8v, I put them back on the charger for anoyher hour and evey thing has been fine today. Is this an indication of pending problems with this battery? I just got it in the mail Monday.