12v battery charger auto cut circuit

12v Battery Charger circuit with Overcharge Protection

12v Battery Charger circuit with Overcharge Protection

This 12 battery charger circuit provides the Automatic cut off facility when the battery get fully charged. Before the use of this circuit you need to adjust the Cut off voltage range for autocut . This adjustment is done by the 10k preset , and a multimeter connected with the output terminals that goes to battery . This voltage range can be set by using any 13v or 14v DC supply which connects the terminals which goes to battery. And move the preset till the green led ON. Once auto cut voltage is set , circuit is ready to use. 

One terminal of Input AC power to Transformer connected through 12 V Relay. When Battery needs charge then Red Led glow, When Charge level goes to about above to 12v or 13v then the Red LED will OFF and Green LED will Glow. And Input Power to the Transformer of charger is also Disconnected by Relay. 

One 555 timer ic is used for detecting the voltage level and Relay is used for disconnect the AC input. 7808 voltage regulator is used for constant supply to the operation of circuit to cut at required fixed voltage.

This 12v battery charger Automatic cut circuit after full charge and provides 6 Ampere high current and this can use for big size Lead acid Battery upto 100 AH. If you want to more high current then replace the transformer with 10A and use 10A10 Diode . You can use readymade 12v  10 A Bridge Rectifier which is available in market.

how to make a 12v battery charger



6A8 or 6A10- 4 pc

1N4007 - 1

7808 ic - 1 pc

555 timer ic - 1 pc


1000uf 50v - 1pc

1000uf 25v - 1pc

100nf (104) - 1 pc 


10K - 1

5k - 1

470 Ω - 2 

Relay 12v 6 A - 1

Preset 10k - 1 pc

LED 1 pc - Green

LED 1 pc- RED

Transistor BC547 -1 pc


Circuit 2


How to make 12v battery charger



Circuit 3


This circuit has maximum current capacity of 1 A only.


12v battery charger circuit diagram

Share this

About the Author


Hi, My name is Aman bharti, I am interested in making and study of Electronics & circuit diagram. I like to share my knowledge and all ideas with people which i get from My Experiment & from different sources. I try to provide any circuit details deeply with test result as possible as. You can contact me on- Email – [email protected]

1 thought on “12v Battery Charger circuit with Overcharge Protection

Leave a Reply

Your email address will not be published.