I have never been happier with my OMG with the 18650 battery extension ring. I go through 2 6ml tanks (1.5 ohm) a day and 1 battery over a 24 hour period. I use the Orbtronic 3100mAh 18650-Industrial NCR18650A Panasonic Cell battery and after 24 for hours of usage, my battery voltage is 3.52V. I have 2 of these batteries and have never reached cut-off. No over heating and excellent results. A little more costly than some, but well worth it.
This combination is absolutely wonderfull!! Going out without having to take spare batteries and cartomizers is a dream come true. Cannot say enough good about the OMG.
Does anyone know the lifespan of the OMG? Should I buy a second one for a spare?