Yeah, 8s A123 is 28.8v (3.6v/cell). Even at the nominal 3.3v/cell, that's still 26.4v. Patrick has mentioned something about a transorb or similar device that shunts power to ground at any value above 26v IIRC. 7s A123 has the same "peak" voltage of 6s lipo (25.2v), so, like Speedy said, it should be fine.