yeah - sorry. If it says E8 in its name, that is probably Chinese wholesaler model E8. I have never seen an adapter for E8. If that was a 2-piece, you were using cartomizers, not cartridges
Do some research and choose something more compatible.
For slim minis...
I recommend either Joye 510 w/ manual batteries (like LiteCigUSA.net or Liberty-Flights.com) (180mah or about 2-3 hours charge for light to moderate
vaping). The longer Joye 510 mega xl manuals are 280mah (about 3-4.5 hours of moderate
vaping) but pretty long (128mm w/ a cartomizers). Put your favorite thinner juices in Boge 510 standard resistance cartomizers.
Or see Vapor4Life.com and Smokeless Image Volt models (KR808D-1) - I recommend manuals but the button is extremely small on the Volt. The larger size batteries (standard Vapor4Life, or 78mm Volt) make 120mm ecig including cartomizer and give 280 to 320mah charge, or about 3-4.5 hours depending on how much you vape.
But if you want really long charge life then you need to skip slim ecigs and go to fat battery models (like Ego, Riva 510 for 650mah+ of charge - see Liberty-Flights.com) and mods. These long-charge models can also use the hotter low resistance cartomizers and atomizers.