rick, racehorse - that of course was my first thought - dual coils - because of my experience with them with eGos but there's a point to where it becomes beating a dead horse, (or riding a hobby horse

....but I think we'll see more of that. With a single coil you can have even a 1.5ohm joye atty go to about 1.3Ω and you most likely will recover, but if esp. the 1.5Ω dual coils get gunked, I think because of the dual aspect, the ohms can drop even further and quicker. That said, as posted early on, I lost 3 Joye eGo-c upgrade batts from dual coil T3D's and as would be expected, I got the short circuit 3 flashes but the batt continued until the next short then died - that's the extra protection from short circuit. Most batts will die upon the first short. The first two losses were on a 1.5Ω dual coil but the last one was on a 2.0Ω dual coil.
Most eGo types will flash 3 times on a short but 6 if you hit the button twice

trying to get it to work. End of charge is more of the 8-10 flashes of the led.
Also depending on the type Joye or Joye clones - the button flashes 4 times when connection is made with the charger and the light goes out and charger goes red. With the Vision batts - at least the ones I had, the button goes off for a few seconds when connected to the charger then comes on and stays on until the charge is complete, then it goes off. I think some of the early Kangers did that too but not sure.