Simple battery charger circuit and battery level indicator with low battery recharge alarm

This is a simple 12V rechargeable smart battery charger circuit. You can use this best battery charger circuit as car battery chargers, Inverter battery charger, Emergency light battery charger etc. An automatic indicator alarm circuit also comes along with this battery charger schematic. The main advantage of this indicator is that a buzzer informs us when the battery needs recharge. This circuit schematic definitely helps for your daily life battery charging applications.Also Read:

Circuit diagram of battery charger

Batery+charger Simple battery charger circuit and battery level indicator with low battery recharge alarm
                                                 Click on the image for enlarged view

Components required

  1. Transformer (230V to 15V or 110V t0 15V)
  2. Bridge rectifier (1N4007 x 4)
  3. Capacitor (470µF, 50V)
  4. Voltage regulator IC 7815
  5. 12V rechargeable battery
  6. Diode (1N4148)
  7. LED Zener diode 9V
  8. Transistor (BC547 x 2)
  9. Resistors (10kΩ, 1.5kΩ, 100kΩ Each ¼ Watt)
  10. Buzzer (12V)

Working of battery charger circuit

  • The charging circuit is build around voltage regulator IC 7815 and two transistors BC 548.
  • The main supply 230V or 110V is stepped down using a step down transformer, and then it is rectifiered and filtered out.
  • That DC voltage is then fed to the voltage regulator IC 7815; the output will be regulated 15V.
  • 12 volt rechargeable battery is connected at the output of voltage regulator and it charges when main power is available.
  • This circuit also indicates the charging status, that is the LED1 is glows when the battery is charged (Above 10.5V).
  • When battery voltage goes below a particular value, LED1 stops glowing and the buzzer produces sound indicating that the battery has been discharged and it needs recharge.

Pin out of 7815, Diode, BC547, LED

8 thoughts on “Simple battery charger circuit and battery level indicator with low battery recharge alarm

  1. I am interested in using this circuit to simply buzz and tell me to turn on my charger…when the battery gets down to 12.4 volts.
    What would I modify to get the buzzer to go off at 12.4 V instead of the 10.5 V noted in the narrative?
    Can I simply omit everything to the left of the battery (the charger) AND can I also eliminate the unnecessary LED? I only want a sound indicator.

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>