Make Your Own LED Battery Level Indicator

In this project I will show you how we can use the classic LM3914 IC to create an LED Battery Level Indicator. Along the way I will show you how the IC works and explain why it is not the most precise circuit for a Li-Ion battery pack. And at the end I will show you how I created my own, more precise Battery Level Indicator circuit with a couple of simple components. Let's get started!

Step 1: Watch the Video!

The video gives you all the information you need to create your own Battery Level Indicator. During the next steps though I will present you some additional information.

Step 2: Order Your Components!

Here you can find a parts list with example seller (affiliate links):

Aliexpress:

2x LM324: https://s.click.aliexpress.com/e/_d8EF8Yr

6x 10k Trimmer: https://s.click.aliexpress.com/e/_dTFyPv5

6x 2k Resistor: https://s.click.aliexpress.com/e/_dTPpXjt

6x 5mm LED: https://s.click.aliexpress.com/e/_dV63r7D

1x Boost Converter: https://s.click.aliexpress.com/e/_d8Eky7d

Ebay:

2x LM324: http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

6x 10k Trimmer: http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

6x 2k Resistor: http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

6x 5mm LED: http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

1x Boost Converter: http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

Amazon.de:

2x LM324: https://amzn.to/2KO65iu

6x 10k Trimmer: https://amzn.to/2u3udnH

6x 2k Resistor: https://amzn.to/2KE0DPY

6x 5mm LED: https://amzn.to/2u9Cbeg

1x Boost Converter: https://amzn.to/2u2Htcb

Step 3: Create the Circuit!

Here you can find the schematic as well as pictures of my finished perfboard circuit. Feel free to use them as a reference to create your own circuit.

Step 4: Success!

You did it! You just created your own LED Battery Level Indicator!

Feel free to check out my YouTube channel for more awesome projects: http://www.youtube.com/user/greatscottlab

You can also follow me on Facebook, Twitter and Google+ for news about upcoming projects and behind the scenes information:

https://twitter.com/GreatScottLab

https://www.facebook.com/greatscottlab

Comments

[xsbiggy]

why does the circuit schematic versus the video show a different IC being used? in the schematic you have a LM324, in the video and header you say its a LM3914

[Clockington]

You can use the LM3914 for a linear Battery level indicator which means each state (LEDs lighting up) is a 10% indicator; however, discharge of batteries isn't always linear so he uses an LM324 IC (OpAmp) to have a custom 6 level indicator which can be adjusted for the non-linear power drain, it is all explained in the video at minute 5:04.

[SilentException]

Hi, nice project :) Been thinking of making something like this but have a couple of thoughts:

- The schematic and the board do not match. There are 3 types of capacitors added and I think a fuse holder? Maybe you could update the schematic?

- The DC-DC converter has 3-24V input specification. So it is only useful for up to 5s LiIon/LiPo battery packs. Maybe 6s if you like living on the edge :) I suppose there are DC-DC converters for higher voltages but I think you can achieve the same thing with voltage reference IC and a voltage divider, correct?

[martonbaksa]

Hey! Based on your comment, you imply that you could use a 1S battery with this circuit, could you provide any ideas on how you convert this circuit to use 1S instead of 4S? Thanks a lot for your help,

Marton.

[martonbaksa]

Hello! I am wondering how you would adjust the potentiometers and everything to make this work with a 1S (1 cell 3.7 nominal battery.) Thanks a lot for any ideas anyone can provide.

[KableClear]

I've made this circuit and keep "bricking" my lm324, as in it becomes a dead short. Can you post values of the three capacitors and/or update the schematic? Thanks!

[DGW]

Please include an explanation of how this circuit functions for beginners. They do not know that an LM324 is a quad comparator or that the resistors make up voltage dividers.

[GianlucaG1]

You need 20V by a step-up converter??? Why? You can simply compare a fraction of the battery voltage! :-)