hi everyone been reading quite a few reveiws on here about dse901. just wondering how long the battery supposed to last between vaping on my e cig mine seems to last about 1- 2hours 3 fags worth at most is this normal. also bought the 36mg of tw cherry liquid filling with about 4 drops of tw and 2 drops of bpg getting about 3 cigs out of this -is this about right how long will a bottle of 30ml last me cheers for any advice