Auto cut off 6V/12V battery charger

Hello friends, today in this video i have shown how to make a simple automatic battery charger circuit for any 6V /12V battery. This circuit needs to be connected between your existing charger and battery. Normally the relay is OFF but when battery voltage increases to the selected voltage the relay energized by the transistor which now disconnect the battery from the charger.
Parts used :-
1. Relay 6V or 12V( as the battery to be charged)
2. Any general purpose NPN transistor
3. 3.3k resistor
4. 10K pot
5. Red led (optional)
6. Resistor for led
Thank you for watching.