My K101 with LR boge cartos hasn't really been doing it for me lately. Plugged in the usb passthru with a 2 amp usb thing, and bam, quality vapor. Compared the K101 with a fresh battery at 4 volts with the same carto, and it's airy wispy bullcrap. The passthru was only set up to 3.6v, and the pt even hits better at 3v than the k101 does at 3.7-4v..... so... what could be the reasons for this?