I gave away all my shorty batteries and only use the extended. I also got the Pila charger and use that now. I have 6 batteries that I rotate through (6 would give me several days between charging, if it came down to it). I've been using the Boge cartos, also about 3.0 ohm, and I tend to keep it in the 4.0-4.4 volt range. Maybe because I prefer a cooler vape than you do, but it also could be that the power output on a ProVari is different than your eGo. The ProVari uses pulse width modulation to control the voltage, so instead of (for example) the output being a steady 4.0 volts, it cycles on and off very fast - several times a second - between 6.0 volts and 0.0 volts. The amount of time it's on vs. off is what gets you the average voltage. At 3.0 volts, it's on 50% of the time, at 4.0 volts it's on 66% of the time, etc. It's very efficient for a basically analog device like a heating coil, and you may find yourself seeking a lower voltage on your ProVari than you're used to with your eGo.