League of Legends (LoL) Question: Problem with Kled’s Ult: Chaaarge?

you should point on the map (or mini map?) where you want the ult to end, if you try just the direction it won't give you the whole range.

So as a Kled main I can tell you that his ult is supposed to be used either with unlocked camera or by clicking on the minimap. I prefer to go with unlocked camera to have a better idea of what's going on and where I should ult, then lock it as soon as it starts. Also, never ult at max range since the enemies will be getting away and you'll waste your ult, get closer first, then ult.