Power transfer systems including a direct current source and a plurality of outputs operable in several modes. A ground mode may couple an output to circuit ground and a current mode may couple the output to the direct current source. The power transfer system may also include a controller configured to iteratively select a pair of outputs from the plurality of outputs. Once a pair is selected, the controller may set a first output of the pair of outputs to the current mode and the second to ground mode for a determined duration. After the duration has passed, the controller may set the first output to the ground mode and the second output to the current mode for the same duration. Thereafter the controller may select another pair of outputs.