It’s not “just slung”… The battery fulfills multiple functions as it is part of the chassis. And nobody is “trying” to make it watertight, it is literally engineered that way. We have made things weatersealed since forever, hell even cars just standing outside in wet cold climates won’t get wet inside even after decades. Yet we can’t make a rigid part of a chassis watertight? You’re grasping at straws brother. You have to crash before water gets in.