I don’t know how accurate it is, but on another thread someone said the max during primaries was $4600. She didn’t donate it all in one lump sum; it was over time.
It's $2,300 per election cycle, with primaries and general election being considered separate cycles. Any donations in excess of the $2,300 limit need to be accounted for separately (cannot be used in the primaries, but with the ability to acquire campaign debt, it's pretty fungible, isn't it?) and applies to the general election contributions.