A hybrid energy storage module, HESM, system, comprising: a first power stage with a first short circuit switch to connect the first power stage to a DC power bus, the first power stage connected between a positive rail and a neutral rail, the first power stage comprising: a first energy storage module, ESM; a first direct current/direct current, DC/DC, converter connected in series to the first ESM; a first power filter connected in series to the first DC/DC converter; and a first neutral lead; a second power stage stacked in series with the first power stage and with a second short circuit switch to connect the second power stage to the power bus, the second power stage connected between a negative rail and the neutral rail, the second power stage comprising: a second ESM; a second DC/DC converter connected in series to the second ESM; a second power filter connected in series to the second DC/DC converter; and a second neutral lead, the first neutral lead connecting the first power filter to the second power stage, the second neutral lead connecting the second power filter to the first power stage, wherein the first power filter includes a switch circuit having the first short circuit switch, a positive ESM lead, a negative ESM lead, and a diode arranged to oppose current flow from the positive ESM lead to the negative ESM lead; and a controller operably connected to the first short circuit switch and the second short circuit switch, characterized in that: the controller has a state of charge, SOC, balancing mode to discharge one of the first power stage and the second power stage by connecting one of the first and second power stages through the other of the first and second power stages with the other of the first and second power stages disconnected from the power bus. a first power stage with a first short circuit switch to connect the first power stage to a DC power bus, the first power stage connected between a positive rail and a neutral rail, the first power stage comprising: a first energy storage module, ESM; a first direct current/direct current, DC/DC, converter connected in series to the first ESM; a first power filter connected in series to the first DC/DC converter; and a first neutral lead; a first energy storage module, ESM; a first direct current/direct current, DC/DC, converter connected in series to the first ESM; a first power filter connected in series to the first DC/DC converter; and a first neutral lead; a second power stage stacked in series with the first power stage and with a second short circuit switch to connect the second power stage to the power bus, the second power stage connected between a negative rail and the neutral rail, the second power stage comprising: a second ESM; a second DC/DC converter connected in series to the second ESM; a second power filter connected in series to the second DC/DC converter; and a second neutral lead, the first neutral lead connecting the first power filter to the second power stage, the second neutral lead connecting the second power filter to the first power stage, wherein the first power filter includes a switch circuit having the first short circuit switch, a positive ESM lead, a negative ESM lead, and a diode arranged to oppose current flow from the positive ESM lead to the negative ESM lead; and a second ESM; a second DC/DC converter connected in series to the second ESM; a second power filter connected in series to the second DC/DC converter; and a second neutral lead, the first neutral lead connecting the first power filter to the second power stage, the second neutral lead connecting the second power filter to the first power stage, wherein the first power filter includes a switch circuit having the first short circuit switch, a positive ESM lead, a negative ESM lead, and a diode arranged to oppose current flow from the positive ESM lead to the negative ESM lead; and a controller operably connected to the first short circuit switch and the second short circuit switch, characterized in that: the controller has a state of charge, SOC, balancing mode to discharge one of the first power stage and the second power stage by connecting one of the first and second power stages through the other of the first and second power stages with the other of the first and second power stages disconnected from the power bus.