Due to the 32-bit restriction you can only have 2.1 billion credits per character - but be careful, the value of your ship, equipment and cargo plays into that, too.
Battleships don't have them, unless you carry over some from your previous ship - once.
I would seriously suggest that on a Restart Ship you do not exceed 1.9 billion.
'I would like to be half as clever as some people like to believe they are' Life is full of disappointments, it is how we handle them that helps to define us, as a person