Tool/software:
Hi,
I have designed BMS with Internal Cell Balancing using BQ7791506. But Cell Balancing not working .Please see the test results below:
4 Cells are in Series. 5AH Battery
Before Charger Connected - Cell Voltages
Cell - 1 -- 3.34V
Cell - 2 -- 3.34V
Cell - 3 -- 3.34V
Cell - 4 -- 3.30V
After Charger Connected - Cell Voltages (Time: 10.08AM IST)
Cell - 1 -- 3.47V
Cell - 2 -- 3.47V
Cell - 3 -- 3.46V
Cell - 4 -- 3.39V
Cell Voltages (Time: 10.13AM IST)
Cell - 1 -- 3.52V
Cell - 2 -- 3.53V
Cell - 3 -- 3.51V
Cell - 4 -- 3.38V
Cell Voltages (Time: 10.27AM IST)
Cell - 1 -- 3.66V
Cell - 2 -- 3.62V
Cell - 3 -- 3.51V
Cell - 4 -- 3.34V
Here 4th Cell is at down side and that cell is started discharging but other cells are charging more than 3.5V. But as per datasheet for BQ7791506 cell balancing start at 3.5V. No cell balancing observed Please explain the what's the problem and why Cell 4 is only discharging more. I have used Rin resistor 33E and Cin 1uF
