Hi,

I would like to build a simple circuit to measure the current charge level of a li-ion cell. The range is about 2.7v to 4.2v. I would just need about 3 LED indicators. I would like the cell to power the circuit itself too.

Maybe an example:

For LED to light up:

LED 1 : >4v
LED 2 : >3.5V
LED 3 : >3V

May I ask if anyone know if such circuits exist? Or which IC to use? is there a smaller version of LM3914?

Thank you in advance for all your help and suggestions. Please ask me if I made anything unclear.

 

Hello,

You could build someting like this:

You can adapt the number of leds to your needs.

This comes from this page of the eBook:
http://www.allaboutcircuits.com/vol_3/chpt_8/3.html

Greetings,
Bertus

 

Hi bertus. Thank you for your help. I saw something similar from the LM3914 datasheet before.

I think I found an commercial product that is small and suit my needs. So therefore, I think this problem for me is solved.

Thanks once again, bertus.

Sorry for the late reply as was busy these few days.