The Battery full charge alarm circuit for a general battery charger. It is simplified circuit and cheap, use one transistor BC557 and display with 2 LED.
All post about the battery indicators
Why your circuit does not work? Because the battery is run out. These low voltage indicator circuits may helpful for you. If you can know before and change a new one right now. It makes you not have to waste time when using those projects.
Simple battery status monitor circuit using IC-7555 or low power LED flasher by ICM7555, need to use LED display status of the battery 6V-12V