FOR US BASED FREELANCERS ONLY - LiFePO4 battery management system, PIC16F17146-based, USA Design Team

FOR FREELANCERS IN THE USA ONLY A 4-cell battery charge / discharge controller. Each cell (14500 config) is 3.65V @ full charge. Feed voltage is 24VDC @ 1A. - Operating mode when 24vdc power is present: Use constant current method to charge when the battery temperature is below 113°F. Cells should not charge when the battery temperature is above 113°F. Cells will not discharge when the battery temperature is above 132°F by disconnecting from the load. Individual cells will be disconnected from the circuit when they are below 2.5V. Disconnected cells will be bypassed in the charge circuit. Each cell is monitored utilizing a unity-gain differential amplifier with the output going into the PIC16. Each cell will utilize a constant current method between 2.5V and 3.65V at 300mA maximum charge current. Each cells will be maintained when 3.65V or above by utilizing trickle charging technique of 20mA charge @ 3.65V. Each cell will be disconnected from the 4-cell series if they are below 2.0V, or above 132°F. If any cell is disconnected, the series line will bypass that cell. - Operating mode when 24vdc power is NOT present: All 4 cells will be connected in series regardless of voltage or temperature. - All battery connections and disconnects are to be gate-driven devices (FET or otherwise). Mechanical relays shall not be utilized. - The PIC16 shall utilize serial communications to store the number of events. Events are defined by a) power on to power off cycle, b) individual battery temperatures falling below 2.5V (recorded with battery # as 1-4), c) individual battery temperatures rising above 132°F (recorded with battery # as 1-4). Scope of project: Design the schematic utilizing standard components from Digikey, Mouser, RS, Newark. Furnish .sch file(s). Write and prove the code for the PIC16F17146. Code shall be written with supporting comments per line explaining the code's purpose on that line. Prefer to stay away from high-density (e.g. QFP100 type, fine-pitch) components. Milestone 1) We will breadboard the design and test the code. Milestone 2) Joint debugging of schematic and code. Final Milestone when project is finished.