Peter, if you are running 4xAAA aren't you at closer to 6V?
If you haven't tried the 18650 yet, you may be surprised by it's performance. It actually runs 4.2V when charged, and because of the high capacity (up to 3000mAh) it doesn't drop as much under load as the little batts. 'Last all day' is an understatement. In my Chuck, the 18650 can vape 3-4 days between charges.
Just a thought, what happens if you blow a little (very little) instead of sucking? That should pressurize the bottle and cause it to push the juice up on its own. I'm just thinking back to when I was a kid and drinking (real) juiceboxes. I would always blow into the straw to pressurize the box and then let the juice feed back out.
If you haven't tried the 18650 yet, you may be surprised by it's performance. It actually runs 4.2V when charged, and because of the high capacity (up to 3000mAh) it doesn't drop as much under load as the little batts. 'Last all day' is an understatement. In my Chuck, the 18650 can vape 3-4 days between charges.
Just a thought, what happens if you blow a little (very little) instead of sucking? That should pressurize the bottle and cause it to push the juice up on its own. I'm just thinking back to when I was a kid and drinking (real) juiceboxes. I would always blow into the straw to pressurize the box and then let the juice feed back out.