Here in this forum (and elsewhre) I read about "charged" black holes. What is the background for this questions? Is this more a question of theroretical interest?
In "practice" :=) black holes should be neutral, because matter is neutral globally. A star is charged a little bit, depending on surface temperature and plasma physics in corona. But this charge will be blast away (with surface material) when the interior of the star collapses to form a black hole. Again, when a black hole "eats" matter from around, charge separation might occur, but only to a limited extent, until the voltage developed would cancel the separation mechanism. (As in case of a star)