Abstract: The invention is related to a battery backup system comprising a power cell array, a controller, and a power inverter. The power cell array may include power cells and a charger to provide electrical power to the power cells. The power cells may include a battery for storing and discharging electrical power, a control input, and a feedback output connected to the controller. The controller may control the operational state of the power cells between a charge state and a power state. The controller may also include a feedback input, and a control output connected to the power cells. The power inverter may convert electrical power discharged from the power cell array to drive the charger and a load.