I started off with that exact setup years ago. The battery should be fine. The T3S is a good tank once you learn its quirks, still have a few of them laying around infact for my old iTaste VV V3. The T3S was Kanger's entry into the bottom coil design along with the Protank series.
The coil is the rascal of it all, bottom set and horizontal orientation. The strength of it is it rarely can get a dry hit due to the coil and wicking is constantly submerged in liquid, this is however its greatest weakness, yep you guessed it "Leaking and Seeping". The tank works off several physics, vacuum, air and liquid elasticity, and affected liquid thickness as well, surprisingly temperature and air pressure. To hot a temperature outside thins the liquid also builds up heat, that whole liquids get warm they wish to expand thing, causes pressure, the only relief valve is the coil and wicking channel. In a controlled environment, store the device on its side, going out into the hot weather or changing elevation, this includes going up or down a building to go outside, driving up and down hills, taking an airliner flight, keep the tank upside down, this puts the air in the tank at the coil so as air increases or decreases, only air is vacated. All bottom coil designs fall prey to this fatal flaw unfortunately, with the T3S I adapted to it like I did my Protanks once I began rebuilding them, thinner liquids I'd wick tighter wicking in the rebuild, thicker liquid I'd wick less, hot weather add more wicking, cooler weather less wicking.
Alternatives to the T3S you could look at would be the Aspire Nautilus Mini would be more eye appealing on an Ego with its transition beauty ring on the Ego skirt threads, its bigger brother the Nautilus Full Size is just fuggly on an Ego on top of top heavy, be cautious though, the Nautilus being bottom coil as well suffers the same above weaknesses but not to the extent of the T3S, the technology of the Nautilus was a year down the road from the T3S when it launched.