Does anyone know where i can get the short 3.7 volt batterys. right now i have the long 17670 and that works great on the Xhaler at 3.7v but i would like the option of putting 2 3.7 volt batteries in the Xhaler and see whats its like to vape at 7.4. and are the short 3.7 volt batts still 17670 or a different number? thanks