OK, this is NOT my attempt to dish a manufacture, but I have recently had a problem with this mod that I bought less than 4 months ago. I quickly moved on to more powerful mods, and it really was a spare I kept at my office. About a month ago I noticed that it would not hold a charge very long, lasting maybe a few hours. As an electronics guy from way back I suspected the battery was shot. I opened the CF4 and found a leaking 18650. It had leaked bad enough to get some acid on the chip and regulator boards. At this point I discarded the whole mess. Like I said this could be a random bad battery, or maybe more mods are affected so If you notice a trend in charge/recharge beware.