Power Transmission Project

Discussion in 'The Projects Forum' started by ywong, Mar 12, 2012.

  1. ywong

    Thread Starter New Member

    Mar 12, 2012
    Hey everyone,
    I'm working on a small design project to pump water up 3 meters (10 feet) and light a 12V incandescent light at the same time. We are given a 12VDC battery, a 500' coil of 16 AWG wire, and the pump and light bulb we have to use. We are allowed to make two circuits, on for between the battery and wire and another between the wire and pump/bulb.

    The pump is 12VDC with a current of 320 mA. The bulb draws 8W. The efficiency and total cost are factors in determining the success of the project.

    My initial thoughts were to use a boost converter before the wire and a buck converter after to decrease the current through the 500' of wire because of i^2*R losses.

    Any help would be greatly appreciated. Thanks!
  2. #12


    Nov 30, 2010
    With the wire calculating at 2.009 ohms, you stand to lose 1.96 watts in the wire. The assignment seems to be how to do 2 conversions for less than 2 watts.

    11.84 watts at the load, 90% efficiency on a switchmode buck converter, wastes 1.184 watts in each conversion. This doesn't seem right. You seem to be looking for 95% or better conversion efficiency. I wonder what a National.com simple switcher can do at these levels?

    Hint: Go to www.national.com and see what's the best they can do with their free online calculators.
  3. ywong

    Thread Starter New Member

    Mar 12, 2012
    What does the Simple Switcher do?