Ambrossiaa as long as the air tube in the carto is clear of excess fluid, hubby's auto will be fine. I vape 50/50 manual and autos, the key is to hold the carto to the light and just do a quick check first.
Since you are using a syringe toss on a .... Plug Condom (
whenever refilling) then flood the entire carto, fill it to the rim, then extract juice back into the syringe so that the top layers of the polyfill are no longer saturated. Remove the condom, hold it to the light and check the air tube. That carto should last for 3 hours of steady vaping (50 draws an hours) before needing a top-off and 5 hours before a refill.
I'm a hardcore juicer and have never killed an Auto Battery in 9 months.
Sidenote:
I also use a flood, extract, flood, extract, technique now and then just to ensure there are no air bubbles in the carto.