Battery Level Indicator Circuit With Low Charge Alarm | Inverter Battery Circuit

It is alarming when you don’t know how much battery left and when will this goes off. Battery charging level indicator is the need for any battery associated with application.The Low battery level monitoring circuit measures the level of your battery.It could be the inverter battery or your car battery.This project is about low battery level alarm circuit.Whenever battery goes down an alarm will generate for recharging.It is very useful in many applications.Most suitable for DC inverter battery circuits.The circuit is used for 12v Battery charge indicator and it uses the IC LM358.


  1. Battery Level monitoring Project Objective
  2. Required Components
  3. Pinout Configuration
  4. Circuit Diagram
  5. Working of LM358 Based Battery charge Level Circuit
  6. Results

01Project Objective:

To Monitor Battery Charge Level and alarm on low battery level.The circuit is based on IC Lm358 and an alarming Buzzer to indicate the level of battery.It is only useful with 12 Volt DC battery.

02Required Components:


 List of Components



 IC LM358



Resistors (1kΩ)



Resistors (4.7kΩ)



Potentiometer-(POT) (10KΩ)



 Diode (1N4001)

ZENER DIODE – 1N5234B (6.2V )




Transistor ( BC547 )



 12-Volt Buzzer / Red LED



03Pinout Configuration:


04Circuit Diagram:

05Working of Project:

  • The Lm358 is the most common and popular Om-amp IC.Used for many applications and projects. LM358 is a dual operational amplifier.Here we are using LM358 with BC547 to switch the alarm when the voltage dropbs below the threshold value.
  • We need to calibrate the circuit.To set the threshold value for turning on the buzzer and LED.
  • Set the voltage to around 10 volts using DC power supply.and adjust the Potentiometer by moving clockwise or anti clockwise untill the buzzer and LED turned ON.
  • Now the voltage is set when you increase the voltage the buzzer and LED will turn off.
  • You can set your desired Low voltage threshold level by moving 10K POT value.Now connect circuit with DC Battery.


The Low voltage battery charging circuit alarms whenever voltage drops below threshold value.This project can be used with CAR battery to monitor voltage level of the batter.This circuit is best used with inverter battery and also with other projects that uses DC battery sources.

In the comming posts we will see More complex circuits related to power and Electrical Engineering.Stay connected and Subscribe to our YouTube channel for more projects Tutorials and ideas.stay motivated and have faith on yourself.

About the author



Mechatronics Engineer - Entrepreneur - Solution Architect
Love writing & Traveling - Being Average isn't a Choice
Stay Happy - Live in Freedom & Always have Faith on Yourself...

Add Comment

Click here to post a comment