battery capacity

Discussion in 'Homework Help' started by JK3, Dec 12, 2010.

  1. JK3

    Thread Starter New Member

    Dec 12, 2010
    3
    0
    What reserve capacity must a battery have if it is required to supply the following emergency services for a period of 4 hours? It should be assumed that under emergency conditions the stated pumps will be required to operate continuously.
    • Navigation lights requiring 300 Watts • Escape lighting totaling 1.2 kW • Emergency bilge pump of 850 Watts • Emergency fire pump of 1.5 kW
     
  2. tyblu

    Member

    Nov 29, 2010
    199
    16
    (300W+1.2kW+850W+1.5kW)*4h = 3.85kW*4h = 15.4 kW-h

    Assuming 12V cells assuming 70% conversion efficiency from inverter:
    (3.85kW)*4h/70%/12V = 458.3A*4h = 1833.2 amp-hours

    This is a good read now: http://en.wikipedia.org/wiki/Peukert's_law
     
  3. JK3

    Thread Starter New Member

    Dec 12, 2010
    3
    0
    Thank you very much for that information, and the website info
     
Loading...