Measure current and voltage of battery being charged using PIC

Discussion in 'Embedded Systems and Microcontrollers' started by goliathpk, Apr 29, 2009.

  1. goliathpk

    Thread Starter New Member

    Apr 29, 2009
    Hello everyone
    Last edited: May 1, 2009
  2. lightingman

    Senior Member

    Apr 19, 2007

    You would need to give more details:-

    What are you using to measure the current? Resistor, hall effect device or what....

    The hall effect current transformers are very acurate and can be read directly by a PIC's analog inputs.

    If your battery voltage is greater than 5 volt, you will need to use a couple of resistors to divide this voltage, as the PIC can only read 0 to 5 volts.

    So basicaly, read the voltage.
    Read the current.
    And and wait for the correct voltage/current condition, then stop the charging.

    If you wish, you could also add an LCD and display the charging condition and status.

    Good luck.

  3. russ_hensel

    Distinguished Member

    Jan 11, 2009
    I am working on building one now. Use op amp to condition the voltage input from the battery into a range for the adc converter on the pic. I use a differential amp with a gain of 1/4.

    On the low side of the battery insert a sense resistor, say 1 ohm for currents up to 1 amp. I use an amp with a gain of say 4 feed it to another adc on the pic.