The jump in difficulty from fabricating a couple of gadgets to fabricating a handful of batteries was immense. These weren't regular batteries but ones that stuffed an incredible amount of energy in a package around the size of a couple of K-coins!
Ves respected the intricacy of the tech he only gained a rudimentary mastery from a fragmentary collection of research papers. He suspected that the Skull Architect who provided them to him likely never expected him to come so far after only a single month of intensive studying.
Everything the Senior handed over to Ves consisted of a treasure hiding behind a trap. It must have been some sick game to the Skull Architect to witness greedy mech designers become ruined after they sought to master knowledge beyond their ken.