Black holes can have charge but a charged black hole would attract ions of the opposite charge strongly and would quickly neutralize. So it would be quite difficult to get a non-negligible charge on a black hole.
If you pump in enough charge that the electrical repulsion is stronger than the gravity attraction, you can then store them safely next to each other, for when you might need one.
It may be a very useful thing if it turns out that we can make small ones.
At the risk of spoiling the mystery of a 50-year-old short story, this happens in the The Borderland of Sol by Larry Niven.
Maybe you can time it to evaporate on your enemy, but that's an incredibly precise timing, and your enemy will literally be able to see it coming and deflect it.
So I would recommend moving your civilization to a Dyson sphere around the black hole before aiming your cluster of LHCs at it.