carl1864:
I'm sure a slight variation could be fine. It will be powering things such as arduinos, servos, motors, a camera, etc. Most of which shouldn't be super picky. Even the camera I'm guessing would still probably run on slightly higher or lower voltage.
That's too loose a spec for me, so I will let others give you specific suggestions. I suspect you will end up needing some voltage regulators (certainly for +5vdc devices) to supplement the batteries you decide on.
Lefty