Looking for a standard 12v Lead acid battery charging circuit with 5v & 12v o/p

Discussion in 'The Projects Forum' started by BtoomBoom, Mar 31, 2015.

  1. BtoomBoom

    Thread Starter New Member

    Mar 31, 2015
    Hello everyone.
    I am building my first robot and am a noob at electronics, so need your help.

    I'm looking for a charging circuit for a 12v Lead acid battery with 5v & 12v output. I mean to run 4 12v geared motors, run by an L293 H-bridge, and an arduino with it.

    So do off the shelf standard circuits which can do this exist? If so, could you please list them. If not, where can I find directions to make one?
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
    Separate the battery charging from powering the robot.

    The H-bridge and motors can run directly from the 12V SLA (no regulation required). You will not be happy to learn that the L293 is very inefficient, and will only deliver ~9.7V to your 12V motor when powered with a battery whose terminal voltage is only 12.5V.

    The Arduino will run just fine with 12Vdc from the battery going into the external DC input jack. The built-in voltage regulator on the Arduino will make the required 5Vdc. I am doing this in one of my projects.

    A small 1A, microprocessor-controlled, three-step charging algorithm Sealed Lead Acid battery charger can be purchased for <$20. I wouldn't try to build one...