The 510 is all I have (and some spare parts from the Blu).
I was using my 510, and was just trying to come up with a way of doing away with carts and ended up mocking something up with spare pen parts slapped onto my 510
about a wek ago.
Using this crap mock-up, so far the only drawback I am seeing is that since the vapor passes the tank on an inhale, the tank sort of "sweats" a little, do it is damp when I pull it out to refill it. Since it can hold about 2ml, luckily I don't have to fill it often.
When trying to figure out how to attach the tank sleeve to the atomizer (without it looking like I stuck two silicone pen grips and a brass cap at the end of my 510) I learned that the inner diameter of the 510 is the same as the outer diameter of the 401.
It wasn't until last night that I learned that the 401 atomizer doesn't have the sttached cart sleeve on it like the 510 (I had never seen one before I went to order them).
Once I get all this hardware, I can see how it all fits together and decide what to do from there.
I don't want to go buy a whole 401 kit, with a pcc, if the parts will not fit together like I hoped and if the tank will not fit inside the 401 sleeve (I used a glass tank, so there is no doctoring that to fit where it doesn't want to).
If it DOES fit into the 401, I may just be ordering more hardware and it will set my project back a little further - but the simplicity will make it worth the wait, my frankenstein mock-up is working great for me in the meantime.
One tank a day, five battery charges, no refills.
When I do my higher-capacity battery mod, I am using a tank design, but I am planning on making it so the tank is integrated into it, and I don't have to pull it out to refill it - and it won't be gathering nicsweat on teh outside.