AA Batteries Draining Unusually Fast!

Discussion in 'General Electronics Chat' started by Thazatoon, May 13, 2009.

  1. Thazatoon

    Thread Starter Member

    Feb 17, 2009
    I have a portable LCD screen rated at 12VDC 8W. I measured the current with an amp meter and it came in at 400mA. I assumed I would be able to power the screen with 10 rechargeable AA 2400mAh batteries for about 5 hours.

    Wrong! The batteries last no more than 40 minutes before the appliance switches off and the power supply is exhausted.

    I then tried 12 AA batteries and measured the voltage at 16.4 volts. The appliance only lasted 50 minutes before switching off. Measuring the batteries afterwards I was still getting 14 volts but there still isn't enough power to switch the appliance back on.

    Can anyone explain what is going on?

    I've just hooked up a 12V 4.7Ah C cell racing pack to the same screen and it's still going strong after 80 minutes.
  2. Mike2545

    Active Member

    Mar 26, 2009
    How many forums are you going to post this in?
  3. Thazatoon

    Thread Starter Member

    Feb 17, 2009
    This is the second forum I've posted the question in Mike. Why?
  4. mik3

    Senior Member

    Feb 4, 2008
    You need only eight 1.5V batteries to get 12V.

    Have you thought how much current these batteries can supply continuously?