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  1. #1
    5 Star Lounger
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    Where does the power go?

    In a laptop computer, where does the power go and in what proportions?

    I guess if you work backward you can discover heat sources in the computer and get some idea from that – a processor with a heat sink and a fan is a likely suspect, a screen so bright it can light a ball park at midnight is another, a drive that is spinning at a standard speed is another. On the other hand both heat and available battery power will depend on the ambient temperature, over which the operator may have no control in a heat wave with a blackout.

    I am wondering, in a purely hypothetical way, what you can do to optimize the performance of your computer to run on as little power as possible for the available battery power, and what you would do to configure a new (or ‘emergency’) machine that would allow you to run your most commonly-used programs with more modest resources than you are accustomed to.

    Are fewer processor cores better or worse? Would a monochrome screen (if one were available) make a difference? What about a monochrome display, like the old familiar-to-some white text on blue background? Most of us have assorted power schemes available, but which is best? Is an SSD better than a mechanical drive for power drain?

    The best investment may be a spare battery or more, and a handy service would be a shop that specialized in ‘your’ batteries and always, to the extent possible, had charged batteries available to swap or sell. I wonder how many industries have such a thing for their in-house laptops, since they would be the first to have an uninterruptible or emergency supply, depending on their needs. Are solar power supplies available for laptops? I well remember the old hand-crank lab generator, but I haven't seen one of those in years. On the other hand, there is no shortage of automobile cigaret-lighter connectors for power for a variety of things. What are people in the heat-wave/blackout in the States using, if anything? And what will they use the next time around?

    Ideas, anyone?

  2. #2
    Plutonium Lounger Medico's Avatar
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    I would think using the Power Saver plan under power options, then having a spare battery would suffice in a pinch as long as you shutdown between uses, and do not do a lot of computing or surfing during those times of power emergencies. The Power saver option will dull the brightness of the screen, shut off the display earlier, power down the HD quicker, things like that, but you usage will be the biggest factor I would think.
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  3. #3
    Super Moderator jwitalka's Avatar
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    Checkout Battery Optimizer at:
    http://www.reviversoft.com/battery-optimizer/

    Once you run the program, it will run a series of tests measuring the effect on battery life on various laptop settings and will set them for maximum battery life. I ran it a while ago and it seemed to be effective but I didn't accurately measure the increase in battery life.

    Jerry

  4. #4
    4 Star Lounger I.M.O.G.'s Avatar
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    It depends on the specific hardware in the laptop in question... However, generally speaking, last I looked at figures, the screen accounts for 30% (LCD + LCD backlight) and everything else pales in comparison. The next biggest consumption in most laptops will be the CPU, if there's a discrete (not integrated) GPU that will be next, then things like drives, wifi cards, etc.

    With that being said, the biggest impact can be made by improved screen technologies. The backlight especially is important - there are LED backlights now which help a lot compared to older laptops using CCFL backlights.

    Processors are always being created with better and better power usage functionality, with increased focus on mobility and the power savings emphasis that goes along with that.

    Graphics has also evolved recently, with the inclusion of technology that enables discrete GPUs to power on during gaming, but power down during web browsing or word processing.

    I expect we'll see more of these types of improvements to lower power usage further yet.
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  5. #5
    Bronze Lounger DrWho's Avatar
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    I've been setting up Laptop computers for as long as they have been made. Minimizing the power drain has always been somewhat of a problem.
    Granted, today, batteries are a lot better than they were over a decade ago, but they still have a very finite life expectancy.

    In the previously mentioned list of power users, the Hard Drive was erroneously or otherwise left out of the list. Just touch the case of any running laptop, in the area where the HD lives and you will quickly see that it's a huge heat generator.

    So whenever I set up any laptop PC, even when it's going to be run primarily on Line Power, I always set the HD to spin down after just five (5) minutes of inactivity.
    That greatly reduces the heat and also the current draw from the PSU or battery.

    I do the same thing on desktop PC's to help keep the HD cooler. Heat Kills!

    It's an easy adjustment and only requires a couple of mouse clicks. It's probably not needed on SSD's.

    To run a laptop beyond the life of its internal battery, the little PSU can be run off of a UPS or inverter.
    A little 200w inverter, powered off of a cigarette lighter plug in a car, can run a laptop almost forever.
    I recently bought one for my own car.


    However, this inverter and deep cycle batteries, could run a laptop for days, without a recharge.


    It can also power most kitchen appliances.

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  6. #6
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    Regarding hard drives, I think they are further down the pareto chart than other components......

    Consider two 2.5" laptop drives that I quickly looked up: The Seagate Momentus 5400 and the Western Digital Scorpio Black

    Both these drives have power a consumption at or under 2 Watts during Read/Write, which drops to 0.8Watts idle and 0.2 Watts sleep. However, spin up current can be around 1 Amp, requiring 5 Watts of power . I purposefully did not select them as being good, bad or indifferent, just common drives from mainstream manufacturers.

    Powering them down reduces their drain by 90%, so does make a tremendous difference to the relative consumption, but, does 2 Watts during read/write and 0.8 Watts idle really turn them into major heat generators, and moreover, how does their consumption compare to other active components?
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  7. #7
    Super Moderator CLiNT's Avatar
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    A solid state drive would be far more power efficient than a mechanical drive, but that still does not negate the need for optimal power management settings.

    Personal usage & habit account for quite a bit too.

  8. #8
    4 Star Lounger I.M.O.G.'s Avatar
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    Quote Originally Posted by DrWho View Post
    In the previously mentioned list of power users, the Hard Drive was erroneously or otherwise left out of the list. Just touch the case of any running laptop, in the area where the HD lives and you will quickly see that it's a huge heat generator.
    Under load, a rotational drive can pull about 8 watts of power. At idle, they can pull about 5 watts of power. That would be for older, worst case scenario, non-green drives. Compared to the other components listed, that isn't much - similar to what the wireless chip pulls and other miscellaneous components. If that section of the hard drive is warm, its due to the mechanical warming up/friction but not due to the amount of power draw.
    Matt Bidinger
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  9. #9
    5 Star Lounger
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    Still thinking

    Since posting the question I have installed an SSD, but it's too early for me to report much from experience (except that it's super-easy to install and get running, in contrast to the experiences reported in the newsletter, although I had to go through the routine a second time for failing to Read The Friendly Manual).

    Thank you all for the contributions, which I found to be most interesting. One quick fix to keep in mind in case of need is to create a flash drive with any flavour of Linux that suits your fancy, keeping in mind that you can tailor it to suit your own preferences, and then use it on any computer that you have permission to use. You can save the files you create or use on the same or a different flash drive, or to the cloud. If your hard drive is dead (or consuming power) it remains 'off' unless the flash drive brings it into play.

    Now that it appears the the screen is Mr. Big, it is reasonable to assume that the more acreage you have the bigger the drain - but for the matter of resolution and the number of pixies dancing across it. Can we refine the math to factor that in?

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