I'm noticing with this vamo (V2) that after a freshly charged battery to 4.2 volts (18350), after only taking a few hits (5 for instance) when I check the battery percentage it has already dropped to 4 volts, this seems pretty extreme. Why is it discharging so fast? I haven't really used the 18650 yet because I prefer the device in "mini mode." My ProVari Mini using a 18490 lasted much longer than this, I don't understand what the problem is.