I wrapped a coil for the kayfun clone i just purchased. 28awg 5 wrap around a 1\8 inch drill bit that came out to .7 ohms. Probably a little too big for the kayfun. Anyway, I screwed on the chimney cap and was going to test vape it on my Nemesis clone using a Sony VTC4 battery. I hit the fire button and the battery tube got really hot almost instantly. It was no more than like two seconds and i immediately let go of the switch, took the battery out which was only slightly warm, and bolted for the deck outside. Two minutes later the battery was cold. I looked over the battery for scorch marks and couldn't find any, it looks brand new. I put it on the meter it read 4v...i think it was around 4.1v starting out...it had been off the charger for a few days before all this. So i set it aside for a day and no leaking. At this point what do you all think i should do with this battery? Retire, or put her back in service and keep a close eye on her? -Thanks