12v Automatic Charger (Auto Cut OFF) | 12v battery charger with auto cut-off circuit diagram

12v Automatic Charger (Auto Cut OFF) | 12v battery charger with auto cut-off circuit diagram

12v Automatic Charger (Auto Cut OFF) - Electronic Project


Power up your batteries like a pro with these Simple 12V Battery Charger circuit diagrams with Auto Cut-off! Are you tired of dealing with dead car power supply batteries or alarm Project system batteries. We bring you two easy-to-build circuits that will charge and protect your batteries from overcharging. These circuit diagrams are perfect for those who want a high-quality battery power supply charger that is both efficient and automatic.

We are sure you’ll love these Simple 12V Battery Charger circuit diagrams with Auto Cut-off! Say goodbye to dead batteries in your car or alarm system with these easy-to-build circuits that will charge your batteries safely and automatically. With these great circuit diagrams, you can charge your batteries and take your power supply to the next level.

The first circuit diagram is an automatic 12V battery charger with an auto cut-off and feature that can recharge car and dry batteries used in alarm Project systems. The circuit is powered supply by a transformer with a secondary voltage of 14-15V and a current of 3A minimum Circuit diagram. A trimmer is adjusted to achieve an output voltage of 14.4V without load. The maximum distributable current is 3A, so batteries with a capacity higher than 36Ah Circuit diagram should not be charged.

Diagram of 12v battery charger with auto cut-off circuit diagram:

auto cut off 12v battery charger

Components Needed for this Project:

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Working Principle of Battery Charger Circuit with Auto cut-off:

In this tutorial, we are going to make a “Battery charger circuit diagram with auto cut-off”. A battery charger is a device that recharges a depleted electrolyte by using direct current. After it has replenished all the electrolytes, the battery’s current supply should come to a halt. As a result, a battery’s performance is determined by the charging process. Nowadays we have become more reliant on batteries, as we require batteries for cell phones, emergency lights, car batteries, UPS batteries, and other fundamental electronic circuits.

They make gadgets more portable, making them more accessible to users. Here we design a battery charger circuit diagram by implementing an adjustable voltage regulator LM317 with an auto cut-off feature. This circuit will give adjustable DC supply output and charge battery ranges from 6 volts to 12 Volts. The LM317 is a monolithic integrated IC, it is a positive adjustable voltage regulator that comes in three different packages.

In this circuit, to step down the AC power supply we have used a (230V to 15V) step-down transformer. And then the bridge rectifier (1N4007 X 4) converts the AC supply into a DC supply. Here C1 and C2 capacitors perform filter operation then finally IC1 LM317 regulates the DC power supply. Variable resistor changes the supply to adjust the pin of the voltage regulator and it changes the output voltage range. Now green LED represents the charging condition and the red LED indicates the fully charged battery.

When the battery becomes fully charged, reverse voltage through the Zener diode (12V) flows to transistor BD139 (The transistor detects when the battery is fully charged. When the battery is being charged, it turned a charge indicator LED on. And turns off when the charging is complete) base and makes it turn ON. Now due to the conduction in the transistor adjust the pin of the voltage regulator connected to the ground and cut the output voltage from the regulator.

These are the chargers that continually monitor the charging voltage of the battery and switch off the charging voltage when the battery reaches full charge. Connect the heat sink with voltage regulator LM317 to avoid thermal runaway.It can deliver 1.5A of load current, and the output voltage can be adjusted from 1.2 to 37 V.


Frequently Asked Questions

What is the cut-off voltage for a 12V battery?

Usually, the power supply low voltage cut-off (LVC) for a 12V battery is 10.5V. It means the battery will stop running the load when it comes down to 10.5 V. This LVC can be set even higher, such as 11V, to improve the Project system battery's life and reduce all chances of deep discharge.

What is the voltage of a 12v battery at full charge?

A fully charged 12-volt battery should read at 12.6 volts on the Power supply multimeter. If the reading is lower than this, you'll want to charge your battery with either a battery charger or by taking your car for a drive.

How do I know if my 12-volt battery is bad?

You can easily perform a voltage test on a project system deep-cycle battery you suspect is bad using any voltage meter (voltmeter) that the Circuit diagram tests for DC. A fully charged, 12-volt deep cycle battery typically has a Power Supply voltage range between 12.8V and 13V, while a bad battery's voltage is below 10 volts.

Why does a 12v battery read 14v?

You are absolutely right, it is because of the alternator. When the car is running the alternator is set to generate around 14 volts which not only charges the battery but also supplies all electrical requirements of the car.

How do I know if my 12V 7Ah battery is good?

Connect the red (positive) probe of the multimeter to the positive terminal of the battery and the black (negative) probe to the negative terminal of the battery. Read the voltage displayed on the multimeter. A fully charged 12V lead-acid battery should read around 12.6 to 12.8 volts.

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