Sharing here some good BMS design, a guy named Byron Davis sent me.

His video is here:

Byron Davis wrote to me on mail: "Here is the schematic attached. it is simplified for clarity but contains everything you need to know to replicate the circuit. The cell discharge circuitry consists of a 5w 4.7ohm resistor and a relay in parallel with each cell. attached is a diagram of the discharge section."

i replied: "really thanks for that friend.

can you tell where to get the Arduino code? ilan"

Byron Davis wrote: "Hi Ilan, I used the Arduino example code AnalogOutSerial as a template. I started by writing the code to check 3 cells in series, Then added more cells to the code. Later i added functions and code to control the charging of the cells, and the communication between this arduino and the one inside the car which displays the data. All of the code is original except for what i used from the Example code AnalogOutSerial. You may use or copy any part of the code or use the entire thing as is. Attached is copies of the code at various stages starting with bms and ending with BMS COM 18 Regards"

Byron_Davis_BMS_Discharge sectionByron_Davis_BMS Diagram

Download  Byron_Davis_Arduino_code