1.) There's a limit on how many Champion Points one can
spend, not how many one can
earn; you still earn CP even when you hit the current spending limit; once that limit increases, you get to spend all those points you accumulated.
2.) The first time you hit Lv. 50 CP 160 with one character, all future characters will start with however many CP you had with your first character when you create another. For example, let's suppose that, with your very first character, you reach Lv. 50 CP 300, and you then decide to create another character: that second character will still be Lv. 1, like with any new character, but will have 300 CP 'in reserve', if you will, for when they hit Lv. 50. Let's also look at a slightly different case: in this case, your very first character only reaches Lv. 40, probably because you didn't like some of the skill and attribute choices you took, and you have no money in-game for a respec, nor enough real-world money to buy enough Crowns to purchase some respec scrolls, so you create a new character, who, as usual, starts at Lv. 1 with absolutely
no CP. You like this one much better, and you take him all the way to Lv. 50 CP 750. By this point, you've exhausted absolutely
everything there is to do with a single character, so you create a third, perhaps of a different class so you can see if you like it better: he starts at Lv. 1 CP 750. You manage to get him to Lv. 50 pretty quickly, so you try out your very first character again, maybe after getting enough real money for some respec scrolls: you find that your very first character is still Lv. 40 with
no CP; this is because there were no characters
before him who reached at least Lv. 50 CP 160. You respec him, though for a slightly different play-style than you originally intended, since you perfected that style with your second character (maybe he was a Templar tank, but you change him into a healer, to see how that appeals to you). You get him up to Lv. 50, but you only have 10 CP, the standard reward for reaching Lv. 50, meaning that, if you want all 750 CP, you need to earn them the hard way. All. Over.
Again. So you ditch him, preferring to create a fourth character, who can reach Lv. 50 much faster than your first one can reach CP 750. While you've been working with characters, a couple new DLCs came out, raising the CP spending cap to 810. After getting your fourth character up to Lv. 50, you go back to your second character, whom you played with a little bit after reaching Lv. 50 CP 750: he's now Lv. 50 CP 775, because you got enough XP for another 25 CP while playing with him originally.
Hope that clears things up!
P.S.: I'll update my sig as soon as start playing ESO again (which should be here in a few minutes); I forget the
exact number of CP I have, think it's 61-62.
