Battery Level Indicator/Alarm

In this project learn how to make an LED battery level indicator using an LM3914 and some LEDs. The device will also feature a buzzer to alert you when your battery's voltage is too low and needs charging.

Each LED represents 10% and when the battery voltage falls below 40% the buzzer will sound alerting you to charge the battery.

To set the 100% voltage adjust the 10k potentiometer connected to pin 5 so that the 100% LED turns on at the voltage at which the battery will be 100% charged. I would suggest connecting a adjustable power supply to the circuit to set these values. For example you want to use the circuit with a 12V battery set your power supply to 12V

Once the 100% voltage has been set the power supply to 10% of the voltage you set in the first step and adjust the 200k potentiometer until the 10% LED lights up. Once this is done you have successfully set up the device and can now connect your battery.

You can adjust the brightness of the LEDs by turning the 10k potentiometer connected to pin 6 and 7 until the LEDs are at a suitable brightness.

If you would like you could build the circuit on a PCB. I have designed a PCB for you so that the circuit is easy to build and easy to connect to the battery using the screw terminals. I have attached the Gerber files for you to use.

Acknowledgement

I thank PCBWay & LCSC Electronics for the partnership.

PCBWay Is a cheap reliable service where you can get your PCBs manufactured. All the PCBs are high quality and the engineers are very helpful and will resolve any problems you may have quickly. Sign up today and get a $5 welcome bonus. Check Out PCBWay Hackster page.

LCSC Electronics Is China's leading Electronic Components Distributor. LCSC sells a wide variety of high quality electronic components at low prices. With over 150, 000 parts in stock they should have the components you need for your next project. Sign up today and get $8 off on your first order.

Website

Check out more of my other projects on my website.