So stealth might work, but even that's a stretch. If Static see her once, he can tag her with an electric charge and track her through it.
So batgirl's only chance is to finish him off immediately, which is a tough thing to do against an opponent whose body can automatically rejoin lost parts, who can generate force fields, and who has incredible reaction time.
Add in the fact that, as Pey said, Static can keep himself safe from the environment without the suit, and Cassandra has few if any paths to victory. Static is massively more powerful and incredibly varied in his attacks, both with electricity and electromagnetism. He shows creative uses and can identify and counter powerful opponents on the fly. Thrown weaponry can be easily blocked and cast aside, and attempting to strike Static in melee is basically suicide. Without massive prep time that Static himself is not privy too, Batgirl is just outclassed here.