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Laptop vs. Small Desktop: Best Bang Per Watt?
Deagol writes "Tomorrow I take possession of a remote, wooded lot with a cabin. 15 miles to the nearest utility pole, my electricity options are limited to those I can generate myself, solar being my primary goal. I'm sitting here staring at my power meter, seeing my desktop & monitor draw about 250W -- a non-trivial amount to generate over a 8-to-12 hour workday. I'd be happy with equivalent computing horsepower (1.4GHz T-Bird, 512M RAM, though more is always better). Should I get a small PC with an LCD monitor, or should I get a laptop? Will laptops draw less power (in general), and if so, will losing the modularity and lower cost of commodity PC parts be worth it? I'd love opinions from those who have been in a similar situation."
I'd be willing to bet that the power savings from getting a laptop, as opposed to a desktop with a LCD, will be sufficient that you will more than make up the price difference by being able to buy slightly fewer solar panels and batteries.
Solar power is not cheap.
"The worst tyrannies were the ones where a governance required its own logic on every embedded node." - Vernor Vinge
The batteries in a laptop will give you the flexibility to work independently (for an obviously limited time) of your home's power source. This might come in handy if you have a solar system that has intermittent output or oyou have other high-draw electrical needs.
...due to going from 120VAC->12VDC that both computers actually use. If you get a desktop, the power supply does it, if you get a laptop the power adapter does it. Maybe the laptop will use less energy because there's no fan on the power supply but either way you are still going to lose a big chunk of energy due to the conversion. I can barely hold my laptop power adapter it gets so warm...that's got to be more than a few watts.
What you should do is get yourself a computer with a 12VDC power input. They sell power supplies that take in 12VDC and have standard motherboard power connectors (although the last time I shopped for one it was using AT connectors). They work well for computers used in cars and boats. A little more expensive, but they basically take the power in and put it right to the motherboard and components.
Speaking of cars, will you have one? Why not use that as the power source? Get a laptop with a ton of extra batteries and keep three or four charging from car adapters wired into the car's trunk or something. If you get a laptop with a mobile processor that sips power, you should have well more than enough power. I work with a Dell Inspiron 600m and I ususually get 3-4 hours per battery. I have two spares I can hot swap so it is easy for me to go an entire 9 hour day running off of batteries.
Also, how much storage do you need? Why not go completely solid state? You could boot from say a CD, load everything into RAM and then power down the CD drive. At that point all you need is a USB key or other flashram to keep your data safe and that should be it. No hard drive, no CD-ROM should mean a lot less power right? Those are both big draws on my laptop.
Those are just a couple thoughts I had...
- JoeShmoe
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-- I wonder which will go down in history as the bigger failure: the War on Drugs or the War on Filesharing
off my Powerbook 12inch power supply:
- Input 1.2 Amps.
- Output, 24V, 1.875 Amps.
Of course, a laptop will not likely draw the most power, the SATELLITE dish you need for the net connection... unless your bazillion acre lot has some GPRS coverage (yeah, right)...
Having lived on a 1000 Acre camp, I can tell you the DIRT is what will really drive you nuts, good luck.
I think he intends to do computer work and actually live in the middle of nowhere. You can stay there much longer if you're getting paid...
If you really need a computer in the middle of nowhere, buy an Apple LapTop (iBook or PowerBook, first needs less power).
...)
Anyway, I'd suggest doing anything but use a computer.
Man, enjoy nature! (wildness, mountains, girls,
Tend to post comments only when drunk
or, he could get an iBook, which i normally get 5-6hrs out of w/ one battery.
just pointing that out.
My iBook (and I assume all Apple laptops) have an Energy Saver Preference Pane where you can control when the computer is put to sleep, when it dims and turns off the screen, processor performance, and if it spins the hard drive down during periods of inactivity or not. It has different settings for battery and power adapter modes, but you can set it to run in the same low power modes when it is on the power adapter.
I spent years living in a place like that. It didn't impede my programming at all. In fact, I believe it improved my software design skills, by forcing me to figure out exactly what I wanted before I sat down to write it.
I think the laptop would be the better idea. Gasoline is costly. If you could get one with a seperate battery charger, and get two or more batteries, you could leave the used batteries to charge at a friend's house or your work and swap them whenever you're out. I have uncertainties about being able to use the solar power for your laptop, depending on your setup.
Listen,
Both a notebook and a desktop system suffer from the same thing: They both run on 110AC. Inverting your DC solar power to that will cost you 30-40% of your power. Converting back to DC (for your notebook/desktop) will cost you a second round of 30-40%. This is bad.
Find a method that can keep you at DC power, ideally as close to the voltages you need. Many of the mini-itx boards will have an option for 'dc power'. These will run on 12-15 volts, and will cost you more like 10-15% TOTAL. Plus, many of the mini-itx boards will consume far less power - - some of them as little as 15-20watts. You won't quite have the speed mentioned (1.7ghz), but close to it (900-1200mhz).
You could use a notebook & build a native DC supply for it - - but many of todays notebooks, regardless of size, draw MASSIVE amounts of power. My dell notebook draws 3.5amps@20 volts [70watts]. That's at 1.2ghz/512megs of ram/15" screen.
As others have pointed out, you'll need power storage. This can be calculated based on your consumption & number of panels used. You can lookup the typical number of solar hours per day for your region.
Solar panels cost around $1USD per watt. The charge controller & storage will also be somewhat costly - - do some reasearch, and purchase a few books on the subject before spending to much...
"Pair this with a small, power-saving bare-bones PC, and I would imagine you would have a setup that would be comparable in wattage to a laptop. Perhaps even better, considering that you are still using gobs of power from the DC->AC->DC conversion when charging the laptop batteries.
Finding a DC LCD Monitor may be a bit harder, but I'm sure they are out there somewhere. If you are feeling adventurous, you could even modify a monitor for DC..."
For the laptop, they sell 12vDC->DC converters in most retail stores. buy.com and bestbuy both sell them. They come with interchangeable plugs where you can fit any model laptop onto it. Be sure to check compatability of the power adapter with yoru laptop before purchase.
As for LCD monitors, most also have external AC Adapters. All you need to do is find out what pin does what in the power connector. Then buy an approprieately speced DC->DC converter (just like the one for the laptop) and you might have to cut and splice the connector yourself.
unless the LCD monitor has an integrated AC Adapter (like the viewsonic VP171B) then this trick will work provided you are technically inclined to sort out which pins provide which voltages and how many amps each one requires minimum.
Please don't underestimate the power savings from going DC only. As long as you keep your main power lines high quality and short (from the solar pannel to your batteries, and from batteries to devices) then DC power can cut your solar pannel requirements down by 30-50%.
Two infinite things: your stupidity and mine. But I'm not sure about the latter. If my sig offends you, I'm sorry.