I drop my power cast in water

@jlmitchell You did not really give us a lot of information about this case. Maker/model number would be great. Anyhow, most of those case have either a battery that charges separately or capacitors that prevent the power when needed. Since it got water damaged you would have to try and disassemble it, clean it with some isopropyl alcohol, check components for damage and replace the battery. You are better off not trying to use it on your phone since you may shorten that out as well. Can I receive another power cast to replace it? Receive it from where? I am sure you can purchase a new case to replace the damaged one.