Table-top LCD's vs Laptop LCD's

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I want to put together a low power computer, but dealing with laptop LCD displays are a royal pain... You have to have a controller with the specs for the lcd display and connections for the more-then-likely propriatory connections, you need to have a specific power inverter to go from DC to AC for the thing, and you need to have clean power supply at the correct voltages for it.

The price adds up quickly.


But one thing I am extremely curious about is the amounts of watts a typical LCD screen uses, like the ones that you use for a desktop computer. A typical 15 inch or smaller (if I can find one) display..

 

[Frightcrawler]

Well, my entire laptop uses 90 watts, so I dont think it would be much more than that. Perhaps 150?

 

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What sort of laptop uses that much juice? Were did you measure it, or is it specs?


If you measured it from the power plug going into block that converts the current from 120 to 12 volts for your computer then your going to get a false wattage reading since power supplies/conversions have a great deal of inneficiencies...

90watts seems like a lot to me for a laptop... What is the mAh rating on your battery, how many cells is in it? It's Lithium-ion, right? how long does it last on it?

 

[jschuk]

He was probably basing it off of the power requirements on the bottom of the laptop (or output on the AC adapter). A lot of the desktop CPU laptops have 90W AC adapters and I have seen a couple with 120W AC adpts. I do believe the desktop LCD consume more power because they are usually brighter. I don't know if they are brighter because they have two FL tubes in them or if they have one bigger and brighter FL tube. That bulb is a big power consumer so you can lower the power consumption if you have an option to turn down the brightness.

 

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How much watts does a typical laptop use nowadays?

Publications and such use a generic "laptop uses 15watts" thing, but to me that seems BS.


Maybe 15 watts if a laptop is idle and running, but not when it's actually working.


I suppose a laptop with a smallish screen and one of those ultra-low power pentium Ms could pull if off.

But not the typical models that most people buy.

Because what is a typical battery pack?

Lithium-ion cells, 2250mAh?

A lithium-ion cell puts out a nominal 3.6v, so you put 3 in a series that will give you about 11.8 volts at full charge and 10.8 volts at a typical charge. A battery pack, I am guessing, has about 12 cells? So that's a total of 4 groups of 3 cells that will give a battery pack a nice 9000mAh at around 10.8 volts, depending on the charge. (or if you do the same thing for 4 cells in a series, and 3 series in parrellel that gives you 6750mAh at 14.4volts)

So a laptop eating 10.8 volts that draws 15watts of energy is going to use about 1400mAh.

That's going to get you over six and a half hours in between charges! Only the very nicest laptops can come close to doing that, or am I just that far behind the times? Or is my math just completely messed up?