Need 6600 mA battery integrated into tracking device

I am looking for an electrical engineer who can analyze the circuitry and electrical requirements of a tracking device and integrate a 6600 mA battery into it. I will also need the battery to be able to charge through a port. You will need to find the type of battery that we will use that must be compatible with the existing circuitry and electrical requirements as well as design the connections and charging port. Need a professional who can get this done quickly and knows how to do everything related to this project. Attached are photos of a smaller battery connected to the circuitry which will need to be replaced with a 6600mA battery. I have additional files about the electrical requirements of the circuit.