So, I am able to get one decent session at a time with my current battery set up, between charges, and I am finding that the Evo needs a good solid warm up, then it performs beautifully! You just have to be patient and let it get really hot at first. I judge based on how warm the battery chamber starts to get, once I feel some heat transferring over to the battery casing (with my lil'chuck) it seems to be sufficiently warmed up and then I start to take slow steady pulls. Once it gets hot, it stays pretty hot for a little while, so you can take a drag, then wait a min or so, and then activate it again, with only a few seconds waiting to get it warm enough to take the next pull. I also noticed once it's really heated up, and giving good vapor, you can stop heating it, but keep drawing on it for a few more seconds and still continue getting vapor from the heat build up in the chamber. I wonder how this will differ from the actual TV battery, as well as over all performance. That goes for the Dart as well, since I have been running the Dart on my ego batteries. Still have to say WOW on the level of medication the Evo delivers on such a small load.