Do you really think you'll need to charge your batteries every week? This seems unlikely to me if you are just using them to power your Zebralight headlamps (unless you plan on lots of night-hiking). I would guess one full charge every two weeks, but you will know your usage better than I will, of course.
With all this in mind though, if I was you, I might reconsider putting the charger in a bounce box (if you plan to take one). You could keep some extra NiMH batteries in the bounce box as well for a quick swap out option in case you are in a rush and need to get out of town. Then, when you get your bounce box again and have more time, you could charge both sets of batteries.
Just food for thought. I'm sure you might have already considered this though...