Join Date: Dec 2010
Location: northern Deep South
Bikes: Fuji Touring, Novara Randonee
Those look like about the size of my Cygolite battery. I've mounted it on top of the stem, and on top of or hanging down from the top tube right behind the fork.
Mount the light first, then play around and see where you can fit it. Top tube is great except for brake cable -- you have to make sure the mounting strap is under the brake. Almost makes me nostalgic for water bottle battery!