Well, I don't have a Vamo V2, mine is a V5, but I'd imagine they are similar enough where I can say that the purple Efest should fit just fine. There is more than enough room in the battery tube even if the purple Efest is a little thicker, and enough compression in the spring if it is a little longer. It's still an 18650, which is 18mm x 65mm (give or take some variance between batteries).