This device is very helpful for everyhome // 12v, 5v & 4v battery charger auto cut off circuit

 This device is very helpful for everyhome // 12v, 5v & 4v battery charger auto cut off circuit

In this video I'm showing you how to make an easy and simple Auto Cut Off Charger For 12 Volt Battery 8ah to 100ah.

There i have used few components including Relay & NPN Transistor.

Input voltage should be fixed at 14.5v

And when the battery voltage will reach 13.9 volts, the circuit will automatically Cut off the charging supply to the battery and saves the battery from over charging.

This circuit is designed to give beep sound also to indicate battery is fully charged.

WORKING

You can see the bc547 is connected to one end of coil pin to switch relay & when it receives enough current at base it will switch on relay. Usually we use preset to set cutoff voltage but here i have used fixed resistance.

10k connected to positive that provides current to 2.2k connected to base of bc547 to switch but to avoid early cutoff, i used 180+470 ohms to groud the current from 10k Resistor and when voltage reaches 13.9v there current also increases so 2.2 k resistor finally receives some current to the base of transistor, and relay turns on and Cut Off supply to battery.

If you increase resistance then (180+470 ohms) cutoff voltage will decrease.

If you decrease resistance then (180+470 ohms) Cutoff voltage will increase.

 This device is very helpful for everyhome // 12v, 5v & 4v battery charger auto cut off circuit

In this video I'm showing you how to make an easy and simple Auto Cut Off Charger For 12 Volt Battery 8ah to 100ah.

There i have used few components including Relay & NPN Transistor.

Input voltage should be fixed at 14.5v

And when the battery voltage will reach 13.9 volts, the circuit will automatically Cut off the charging supply to the battery and saves the battery from over charging.

This circuit is designed to give beep sound also to indicate battery is fully charged.

WORKING

You can see the bc547 is connected to one end of coil pin to switch relay & when it receives enough current at base it will switch on relay. Usually we use preset to set cutoff voltage but here i have used fixed resistance.

10k connected to positive that provides current to 2.2k connected to base of bc547 to switch but to avoid early cutoff, i used 180+470 ohms to groud the current from 10k Resistor and when voltage reaches 13.9v there current also increases so 2.2 k resistor finally receives some current to the base of transistor, and relay turns on and Cut Off supply to battery.

If you increase resistance then (180+470 ohms) cutoff voltage will decrease.

If you decrease resistance then (180+470 ohms) Cutoff voltage will increase.