I wouldve gone w/ a V2 as well, so good choice there
And I use 7.2v 4500mah RC Car Batteries to power my 722. They would work equally well powering a v2 because i used to power my old v2 w/ them. 2 or 3 7.2v 4500mah rc batteries would power your v2 fior MANY HOURS
Just get an rc battery plug>4-pin xlr cable made like i hyave and youre good to go. Only takes around 2 hrs to charge a DEAD battery too
I also used to use ecocharge batteries to power my v2/v3 but those are like dinosaurs now. But if you can find ONE 7.2v ecocharge and charger, then you'll be SET, and that would weight just about asd much as the 3x7.2v 4500mah rc batteries....
Good luck on yer quest