The application describes systems and methods for a modular portable power plant system including a first module having a first bank of one or more batteries and a second module that is detachably connectable to the first module. The second module includes a first DC to AC power inverter that is in electrical communications with the first bank of one or more batteries. The first module can be configured to house a first bank of one or more batteries arranged in a first configuration or a second configuration such that the first module includes a reconfigurable battery rack assembly arranged to be reconfigurable to provide support for a first battery set in the first configuration and a second battery set in the second configuration.