water pump

Discussion in 'General Electronics Chat' started by teratron, Sep 24, 2008.

  1. teratron

    Thread Starter New Member

    Sep 22, 2008
    I bought a water pump from Harbor Freight Tools, item # 94639- 100watts., that works on 12vDC, primarily to be used in a boat, but I want to use it at home to pump water. I need to buy a power supply with 120vAC/12vDC. I need to know how many amperes should be the power supply to power the pump. You can check the pum spec. at www.harborfreight.com
  2. scubasteve_911

    Senior Member

    Dec 27, 2007

    Water Pump
    P = 100W
    V = 12V
    I = P/V
    = 8.333A

    For the power supply, you should be able to specify a 100W supply at 12V. Supplies are commonly spec'd in power, rather than current and voltage.

    @120V, you will draw 100/120A, 0.833A

  3. triggernum5

    Active Member

    May 4, 2008
    A PC psu should do the trick even.. The old AT psu I have here says its rated at up to 9A @ 12V.. Most modern ones are bigger.. You can jumper an ATX psu on by shorting the green wire going to the MB connector to gnd..
  4. SgtWookie


    Jul 17, 2007
    I have an old Compaq 250W ATX form factor supply set up as a bench supply.
    The +12V is limited to 8A, so it would not be enough to run your pump.
    You will need to check the supply you're considering for such a conversion to ensure that it will supply enough current.

    Marlin P. Jones has a supply that will work; it's about $33.
    Last edited: Sep 24, 2008
  5. vetterick

    Active Member

    Aug 11, 2008
    You might just buy yourself a 12V automotive battery charger, just get one 10A or better.