Not sure how you get to 5 batteries Marzy Baby? I use pretty much one battery all day and only change to a second battery late afternoon or early evening. I go through around 10-12ml's a day.
running a 0.4ohm dual coil setup on the reo chows the battery.
being single battery is its weakness. it takes away alot of options in terms of builds and wire you can use.
the reo definitely was not intended for subohm in my opinion