12V power supply vs 12V battery charger

Discussion in 'Power Electronics' started by Chassis, May 21, 2015.

  1. Chassis

    Thread Starter New Member

    Apr 21, 2015
    I am trieng to figure out the difference between a 12V power supply and a 12V lead acid battery charger. Can a power supply be used as a car Battery charger aswell or can somone please explain to me the difference.
  2. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    A charger needs to provide a controlled voltage higher than the battery voltage in order to charge it, and also needs to control charging current. Its voltage needs to change as charging progresses.
    A 12V power supply will provide a constant 12V, and may or may not have a current limit/control feature.
    JWHassler likes this.
  3. wmodavis

    Well-Known Member

    Oct 23, 2010
    A float charger for a lead acid battery is a constant voltage device and a regulated power supply is ideal for that.
    Must set the voltage at optimum value depending on designated battery use and/or manufactures recommendation.
  4. Kermit2

    AAC Fanatic!

    Feb 5, 2010
    some battery chargers can generate voltages as high as 15-16 volts when connect to a low resistance load.
  5. alfacliff

    Well-Known Member

    Dec 13, 2013
    most "12" volt supplies are actualy 13.6 volts to operate car stuff, 13.8 is the normal engine running, car voltage and will charge lead acid batteries. the majority of battery chargers have no current limitting other than maybe a fuse., chargers are also not known for having good filtering, so they make lousy supplys for testing equipment.
  6. MrChips


    Oct 2, 2009
    In order to properly charge a lead acid battery you need three charging stages each with different current/voltage requirements.

    Check out the Battery University.
  7. gerty

    AAC Fanatic!

    Aug 30, 2007
    And if you're thinking of using a car charger for a power supply be advised most of the newer ones have a circuit built into it that requires you to connect to a battery before it'll turn on. The purpose of that is to prevent you from connecting it backwards(reverse polarity) and blowing something up. Yes the circuit can be bypassed ..