1) The tanks are simply too small, you should have been relatively heavy smoker.
2.) If you get the wrong train technology Liquid in your mouth - not very pleasant.
3.) The tanks siffen - Eventually, after repeated filling the tanks at the evaporator not quite tight.
My recommendation, which is also favorable, would be:
2 Joyetech-Akkus650 mAh: 13.89 X2 = 27.78
1 Joyetech USB charger set: 14.00
2 Clearomizer CE4 + 2.1 to 2.4 ohm: about 10.00
Total: 50 - 55 Euro
That's it. Now you have a complete set only with better taste, better flash, no siffen, more content.
Everything is much easier to handle and less cumbersome (for beginners plus). Important: Please pay attention to the Ohm-number !!!
And the best: Everything is available here at Amazon!