You could get Joye Ego (large version of 510) or Joye Ego-T (though many have issues with the
tanks and switch to cartomizer, like most atomizer users do). Ego is 3.4.
Or go for something 3.7v - like the Riva 510 kits at Liberty-Flights.com (their stock is new 3.7v kits from the Riva manufacturer who makes the 3.7v ones now), and many like Kgo which I think is also 3.7v
Or go for a mod - there are so many. Then your batteries will be standard industrial protected Lithium Ion or AW IMR batteries. There's everything from $20 plastic box mods up to wood and metal mods as high as $200. One new simple mod is Bolt (see it at Madvapes, LiteCigUSA.net, probably at
smoktek.com). You could look at variable voltage ones like Provari or the New Lava tube or its mini version, or plastic VV boxes (I recommend only ones with Evercool aka varicool circuit -
smoktek.com has one). Check out the ecig mods database and if you see something you like come back here and research it to see if it has problems.
Best e-Cig Mod List | e-Cig Mods Database
And BTW if you were in the armed services, there is an armed services forum on ECF.