Thread:Sentry 616/@comment-27144409-20151216215042/@comment-28505610-20160609152431

It is just a theory but I think Aura recharges based on nutrition and emotion. They have to refuel their body and their Aura and it seems to be refilled when they are full. Aura can also be supercharged or drained by emotion. For more info on the concept of aura I recommend the Nicolas Flamel series The Alchemist.