From an electronics standpoint - it all depends on charger output, battery output, atomizer resistance.
If you've got a 3.7v charger, you'll never push more than 3.7v into the battery, and may damage the battery (but I'm not sure).
If you've got a low resistance atomizer, you'll push more wattage
through it than with a lower voltage battery. Most wattage over 11 is pretty smokin' hot. Even the Evolv darwin will limit to about 12.6w (if memory serves.) My personal sweet-spot is in that 8-11 watt range for 306 atomizers. Either way - if you're in the 3.4-3.6v range, and your atty's / carto's are in the 2-3ohm range, they SHOULD be fine, but you'll be running hotter, increasing vapour, flavour, and TH, but reducing the life of the atty, and possibly the battery if it can't handle the drain.
Simple calcs.... I=E/R, P=I(I)*R
(Typical cartos)
3.3v @2.5 ohm = 4.356 w (Is this thing on?)
3.7v @2.5 ohm = 5.476 w
4.2v @2.5 ohm = 7.056 w
5v @2.5 ohm = 10 w
(Some LR atomizers)
3.3v @2.0 ohm = 5.445w
3.7v @2.0 ohm = 6.845w
4.2v @2.0 ohm = 8.82w
5v @2.0 ohm = 12.5w
(Typical LR atomizers - huge current draw here...)
3.7v @1.4 ohm = 9.75 w (Crackle)
4.2v @1.4 ohm = 12.6 w (Sizzle)
5v @1.4 ohm = 17.8 w (POOF!)
(High resistance atomizers for VV units...)
3.3v @ 5ohm = 2.178 W
3.7v @ 5ohm = 2.738 W
4.2v @ 5ohm = 3.528 W
5v @ 5ohm = 5 W