I own 2 map tanks and use them on eGo batteries. LOVE them!!! You are going to want to use the 3.2 ohm ce2's in your map. The best way to get a map tank is to click on that NOTIFY ME! button on the COV website. You will have to watch your email because once those emails go out, the maps disappear pretty quickly, they are hard to come by, I feel blessed that I have been able to get 2 of them, I got the big ones, not the mini's. I just dont want to mess with stuff more than needed. What I found is the big one holds up to 5ml, but I only put 4 ml in it. It lasts me all day and sometimes a bit more than a day. When it's empty, I clean it and it's brand new again. My first map tank ce2 lasted me about 3 weeks before I had to replace it, and it would have lasted me a bit longer had I not broken the wick, the ce2 was still in working order.
Bottom line... I highly recommend a map tank!! Worth every penny! No more carts and filler mods, no more tanks and dry hits or leaking and expensive attys. Dont get me wrong, I still own the eGo-T's, and use them occasionally, but I keep them more for converting others to vaping as I lend them out for smokers to try, but the attys cost more than they are worth in my opinion. I can get a 5 pack of ce2 XL's for about $12 which is the cost of 1 eGo tank atty, and I can fill up my map tank and not mess with it ALL DAY. To me, this is a no-brainer.