Need help on building a li-ion voltage tester

Discussion in 'The Projects Forum' started by ici7ee, Jun 21, 2009.

  1. ici7ee

    Thread Starter New Member

    Jun 21, 2009

    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.
  2. bertus


    Apr 5, 2008
  3. ici7ee

    Thread Starter New Member

    Jun 21, 2009
    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.