Without photographs it is hard to comment.
But even if the hinges and lock were not repairable, I'm pretty sure that a repair could be effected with small stainless steel hinges and a cam lock, I would give careful consideration to the hinge and lock fixings and ensure that any drilled holesfixings were suitably sealed.
I would not be replacing the battery box if I could effect a door repair.
Hopefully someone will come along with a quick fix for you.