Abstract: A method and system is disclosed for maintaining a synchronized state of charge of a plurality of independent parallel interconnected battery packs. The system is modular and scalar and relies on an embedded BMS in each battery pack for operation, thus eliminating the need for an external BMS. Three circuits are provided in each battery pack which include a monitoring circuit, a protection circuit and a signaling circuit. The signaling circuit includes a shared status line connected to all interconnected battery packs that is monitored by each embedded BMS by way of a monitoring circuit When an initiating battery pack encounters a condition to that forces the battery pack off line, the BMS of each interconnected battery pack will activate the switches associated with its protection circuit and simultaneously signal this status to the other interconnected battery packs by way of a shared status line.

Abstract: A method and apparatus for battery cell temperature maintenance including determining a battery cell temperature of a battery cell is below a temperature threshold and initiating a temperature maintenance mode. Upon initiation of the temperature maintenance mode, determining a charge level of the battery cell and initiating one of a charge sequence in which the battery cell is charged and a discharge sequence in which the battery cell is discharged. The charge sequence initiated upon determining the charge level is equal to or less than a discharge limit and the discharge sequence initiated upon determining the charge level is equal to or greater than a charge limit.