Just did a longer term test on my Hotcig150 and Skyline
With two fresh LG HG2 batts (brown chocs) I got through just over 5 tankfuls of juice on the Skyline. Vaping at 18-20 watts.
This was after the fifth tankful - the battery meter was nearly on empty
A little bit more vaping and it went flat on the mod
I estimate about 3ml per tank so about 15ml of juice (maybe a bit more) on the batts. So about 8ml per batt.
Am happy with that. Not always having to change batteries.