Many Chinese say "ever" when they mean to say 曾经 (ceng2jing1). But that word can be translated to 曾经 only when it's in a question, e.g. "Have you ever been to Shanghai?", or in a negative sentence where it changes to "never", e.g. "I've never said that". Otherwise, it means "always", e.g. "Finding the cure for cancer seems to be an ever-lasting process without an end."
If you really want to say 曾经, say "once" instead, e.g. "Once I had a car accident."