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?
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?