How do you measure a notebooks watts?

how can you know how many watts your notebook is using, in order to determine est. battery life? that is the factor here right? watts?

 

RMClock estimates your laptop's instantaneous power draw under its battery page. I've found it to be a fairly accurate figure, but your mileage may vary. You can also use something like the Kill A Watt to measure your power draw at the outlet, but this doesn't factor the inefficiency of your power supply. If you're really hardcore, you can work multimeter leads into the input of your laptop or the output of your adapter and read those figures.

 

hmm i have a multimeter. i r hardcore?

can anyone explain simply how to do this? i just stick the leads into the battery hole?

 

http://www.freewarezoom.com/archives/batterybar
check this link

 

If you don't know what you're doing, you probably shouldn't do it...

You need to identify the positive and ground lines coming out of the adapter, bridge the ground and the signal line (if your adapter has one) (the implementation is up to you; I don't know how I'd go about this short of breaking the adapter output line), and measure both the voltage and current on the positive line. P = IV and you get the power draw.

I take no responsibility for you shorting your adapter or computer...

(and obviously someone correct me if I'm wrong here; I've never had the need or guts to try this myself)

 

didn't know you could short things using a multimeter. as far as i know they were made to stick into wall outlets =p

 

The ones that stick directly into outlets will do just fine.

 

you cant measure amperage the system uses by plugging a multimeter into the wall. All it will read is ~110V AC
You can get a device called a KILL-A-WATT, which measures the amount of power your system uses. This is the most accurate way second to a ohmmeter (those things which clip around the wire, which show current draw)
In experience, RMCLOCK isnt usually right but it will give you an idea of power usage

K-TRON

 

hey man like this buy it i have it at home
http://www.amazon.co.uk/Plug-Power-...1?ie=UTF8&s=electronics&qid=1239916530&sr=8-1

just now my laptop consuming 60w am on internet and high performance selected ..

 

I have the exact same one, it works great.

 

awesome, and these are accurate?

 

Don't know about the specific one linked, but the Kill A Watt I have is accurate to a tenth of a watt, so I'd assume this one gets about the same. Likewise, you're still not factoring power supply inefficiency at the outlet, so your numbers will still be an estimate.