Hi @Rupesh one thing I would like you to check is to see if the charger is working during supply mode.
When the charger is plugged into the robot and supply mode is on, if you run in the terminal stretch_robot_battery_check.py
The voltage should be greater 13V, to indicated the charger is correctly working
if it does show greater than 13V I would suggest leaving it on there for a couple of hours (4-5) and then take a look at our forum post on Repairing Unhealthy Batteries to run a repair cycle on your robot