For how long???
Vapers are an obsessive bunch, aren't we.
Think what you'd do when you smoked cigarettes. (Assuming you used to. I think it's a safe assumption.)
Personally, when I went out into the wilderness, which used to happen for 2-3 weeks at a time, I just packed a pack per day. Sometimes I smoked less that than, especially when I was getting a lot of exercise, so I knew I was covered.
Likewise- I get through about 1000mAh of vaping power a day. (Really more like 900, but I like to be safe.)
So if I were going on a week wilderness holiday, I'd pack:
10 750mAh batteries.
Or 3 2600mAh batteries.
Or 8 1000mAh...
you get the idea.
And pack a few extras- but don't oversweat this.
when I smoked, if I ran out of ciggies, I had to do without for a little while.
If you run out of power, or juice, same same.
It's why they call it roughing it.
Ande