Gaming notebook battery / power consumption

Discussion in 'Hardware Components and Aftermarket Upgrades' started by Razyre, Jan 22, 2014.

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  1. HTWingNut

    HTWingNut Potato

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    Most external PSU's are 90% efficient.

    See the efficiency marking by energystar: http://www.energystar.gov/ia/partne...International_Efficiency_Marking_Protocol.pdf

    For a power supply mark "V" (most laptop ones are): "Power supplies with greater than or equal to 100 watts input power must have a true power factor of 0.9 or greater at 100% of rated load when tested at 115 volts @ 60Hz."

    Not Alienware, but similar config, see Clevo SLI power consumption here: http://forum.notebookreview.com/sag...s-sager-np9390-clevo-p375sm-review.html#power

    Up to 330W draw form the wall with quad core and SLI 680m!

    That being said, it gets up to 2.5 hours on battery with light web browsing!
     
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  2. Qing Dao

    Qing Dao Notebook Deity

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    A PSU's rated wattage is its maximum output, not what it pulls from the wall. So for example, a 240 watt power supply can deliver the full 240 watts to the computer. If this power supply is 90% efficient, it would pull about 267 watts from the wall when providing 240 watts output.
     
  3. HTWingNut

    HTWingNut Potato

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    Exactly. That was the point. If you measure pull from the wall, you can estimate power delivered to the machine by using the PSU's rated efficiency, so if 300W is pulled from the wall that's ~ 300*0.90 ~ 270W.
     
  4. Razyre

    Razyre Notebook Evangelist

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    Ah I was completey mis-understanding the efficiency ratings. Because I hear a lot about low end crappy PSUs not being able to deliver their full power rating, I imagine the same with higher end PSUs. So my 750W 80 Plus (No rating) would draw 900W from the wall. I hadn't taken this into consideration when I was measuring the power at full load either. So while I have 600W when using a 7950, 560Ti and 4770K all OC'd at the wall, I'm actually only sending around 450W to the components, right? I Imagine the 7950 is using around 180-190W, CPU around 130W and the 560Ti around 150 which comes out around 465 so I'd say that's about right. Leaving a little overhead for the rest of the components let's say around 480-490?

    I thought my power supply was conking out using all these components at the same time but I think things were probably just getting too hot (bad airflow in my case atm) since it's a fairly decent PSU as they go.

    Also, I looked into Lithium Ion batteries, and it's possible to get one that draws a crazy amount of power at load. I'm talking a good 30-40A or something crazy. So this no longer seems as unbelievable. These are single 3.7V cells though so I presume you'd combine 4 and divide the output by how many cells you've got or something and then you end up with 10A at 14.8V which'd be around 150W output. I imagine this is likely what that Alienware battery can do, hence why it throttles so much under load because it needs a 240W supply at the wall you've got a lot of missing overhead there.
     
  5. HTWingNut

    HTWingNut Potato

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    Not only that, but if you drain your battery at max amps, it will get super hot and possibly melt down or explode. You'd drain your battery in minutes too even if it didn't.
     
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