I think I understand your problem perfectly dcav. I experienced the same thing with my first e cigs in 2008.. Things have changed a lot. The VV I have provides consistent full vapor production until just before it start flashing at me for a recharge after hours of use. Nothing like the old batteries that started strong-ish and quickly faded to weak vapor production. I recently considered a passthrough when trying vaping again. It's a logical thing to assume, I think, that they may solve the weakening power problems of e-cigs past. However I've found the newer batteries fix it.