I would suggest the kgo vv from hoosierecig.com man is great it goes from 3.6 volts you can use it while its charging and its got a lcd screen. it dont lite up when you press the button. your can turn it on or off. has a nice battery bar in the lcd. its Li-po last about 4-5 hours on a full charge with a single coil carto or the vivi nova tank. and hoosier ecig has super fast shiping your in ten im in alabama i got my order in 3 days with a few custom house blends that make it take a extra day regardless. carges to full in about 45 mins its fast for sure.
KGO V.V. 650mAh
heres a review i did showing the vivi nova tank and all that on it
Kgo vv Battery 3.0-6.0 volts review - YouTube
it cost 25.99 and i got a coupon code that in the card you can use if you wat any one can its
5off
shipping is free with orders that are 50 bucks or more but if you dont want to spend 50 bucks it was like 2dollars and something.
heres the vivi nova tank witch is worth the money regardless what your get
mega vivi
Vision Nova Tank Clearomizer V3 Mega
mini vivi its the same size as the battery.
Vision Nova Tank Clearomizer V3 Slim
and heres a adapter you dont have to have these for the tanks to work just make it look like it all one peace 3.5 mill for the mini vivi and 6 mill for the mega vivi
Adapter for Dual Coil Tanks
hope this helps