# Power usage

1. Mar 25, 2007

### barneygumble742

hi,

the attached image is from the back of my laptop.

i'm trying to figure out how much watts it consumes per hour.

i know that power is current multiplied by volts. so its 90.09 watts = 4.62 amps * 19.5 volts. is this the watts per hour?

thanks,
mark

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2. Mar 25, 2007

### Averagesupernova

I'm not sure, but the 4.62 amps may be what it takes to run the laptop as well as charge a low battery. It may not take this much current all of the time. Once the battery is charged current consumption probably drops off.

3. Mar 25, 2007

### dlgoff

"...is this the watts per hour?"

This is the amount of power consumed. The energy from 90 watts for one hour is 90 watt-hours; for two hours is 180 watt-hours.

4. Mar 25, 2007

### sunday

And you have to take in account the efficiency of the power brick, usually in the range of 90%, so the total power will be around 100.1 W