+ravi ranjan battery will discharge if you will not disconnect it and yes you can use switch. copper wire have high conductivity so you need to give high supply for heating it.
If You have not nichrome wire checkout wire used for normal wiring. it not should be of copper. stainless steel wire will work fine it will be silver color and most probably shining surface.
If You have not nichrome wire, checkout wire used for normal wiring. it not should be of copper. stainless steel wire will work fine it will be silver color and most probably shining surface.
