I've done that math using @Gabriel's exact cash limit and if it's like @St.Denis said, and it takes into account sell value, then my BS scanner Serenity and can hold a bit over 2 billion with the current equipment.
The question that begs to be asked, why do you want to max it out when you can get close, by restricting it to about 1.9 billion?
If you make a mistake, the character becomes corrupted and unusable.
Just use a Restart Ship and store the money on there, making sure you have put sufficient time on it to stop it from getting inactivity wiped.
'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
It's a personal preference thing, I like having all my money in one place. I want to have a single bank, otherwise I will just trade forever with no reason at all. This way, my bank limit is 2bill. When it goes below, I can trade again to bring it back. I won't ever need more than 2 billion.
If you do it right, you can make a lot of money building Bases.
'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