Not necessarily Charlie did die in All Dogs Go To Heaven 2.....of Boredom

Yeah. I'm sure that he never died in the series. He did go to heaven a few times cause Annabelle called him there but never died considering that he is a guardian angel.

I think CharlieFan_2 is right; he only really dies the once (in the first film) although I suppose you could say he dies twice as he does so at the end of the first film too.
In my personal opinion Charlie is sort of in limbo throughout the first film anyway (hence he doesn't actually die until the watch does) so in theory he dies once, remains in limbo (almost like a ghost) and then simply moves on to Heaven at the end

In the second one it's the same kind of deal because he is definitely a ghost and in fact he is given a 'second chance' at life in the end

I can't remember much of the series but I don't ever recall him dying again? :O

No idea. I never remeber seeing him die if your talking about the T.V. series. If you mean the movies he only really died once.