I have a solar charge controller which can charge 12volts batteries. I have two 12 volt batteries which are connected in parallel. I need to have 24volts output without using dc-dc step up converters. Can I connect two 12 volt batteries in both parallel and series? like first having a parallel then having a series connection with some Diodes to control the current/voltage flow. Is it possible? are there some best practices?

EDIT: goal is do charge/discharge the batteries simultaneously.