I tested one of my Reos with an AW 2200mah 18650 in it with an IKV LR2.0 306, and under load it was pushing 4.04v, with a hot off the charger battery, so comparing a fresh "big boys" batt to the Provari at 4.2v, may not seem like a huge leap, but an hour down the road, the Grand would only be...