I've just checked Wiki on this. It was a name used by black slaves for the slave owner originally. Why 'Charlie' it doesn't explain. Also used for a black man trying to act white. So was that a black trying to lord it over other blacks? I wonder if possibly it was a mulatto half caste too who had extra powers over the other slaves? Wiki says the name/term has now gone out of use.
Thanks for the heads-up on this. I didn't even consider Wikipedia. It's a very informative article. Thank you again.