Energy Management of Blood Pump Controllers

A medical system comprising:

• a medical device configured to be worn by a user or implanted in the user;
• a first external battery comprising one or more battery cells and a first external battery output connector configured to output electrical power discharged by the one or more battery cells of the first external battery;
• a second external battery comprising one or more battery cells, a second external battery input connector, a second external battery output connector, and a second external battery controller;
• wherein the second external battery input connector is configured for coupling with the first external battery output connector to receive the electrical power discharged by the one or more battery cells of the first external battery, and wherein the second external battery controller is operable to control distribution of the electrical power received by the second external battery from the first external battery to simultaneously recharge the second external battery and output electrical power via the second external battery output connector to power operation of the medical device;
• and
• an external controller comprising an external controller input connector and an external controller output connector, wherein the external controller is configured to control operation of the medical device, output electrical power via the external controller output connector to power operation of the medical device, and receive electrical power from the second external battery via the external controller input connector.