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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."
Duder, if yr headed that far out into the boonies, you might as well pawn the damn computers and buy an axe and a box of matches. Seriously.
sig not found
I feel that my laptop gives me more bang for my buck. It draws much less power, and I can take it around with me. I like it much more than the cheap pc's we have at work (which would be a low power desktop) but LCD monitors are nice, but the quality of the lcd's on a laptop are just as good.
And I didn't know Ted Kaczynski was even eligible for early release...
-- @rjamestaylor on Ello
...that way you can always charge it up from someone elses sockets.
An infinite number of monkeys will eventually come up with the complete works of
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.
The big problem you'll face on solar is the ol' "It don't work when the sun ain't around." That means you're better off getting a laptop for a few reasons. 3 or more hours of battery life can be very handy and you can march around with it, meaning you could leave lights off at your desk and stroll over to the kitchen with your laptop, saving electricity in two ways, the lights and that stored in the batteries.
Another option is get a UPS for your desktop. You can run the machine off of that when the power goes out, night, etc. and they are relatively cheap...if you get a 4 hour one... and can power other devices. The laptop and the UPC will trickle charge while juice is flowing, so you can be pretty sure that when the sun does set, you won't miss a beat with your tech.
Now... how exactly are you going to get on the net? Satellite? Pigeon?
"Life's funny sometimes." "And sometimes it isn't." --Cat's Cradle
It should be obvious that there are more low power options in laptops than PCs.
However, be aware that some laptops are really just mobile desktops, in that they're fast, hot, and hungry.
There are plenty of good low power laptops out there. Just start by looking at battery life.
"Small PCs" are not necessarily better for power consumption than big boxes. It all comes down to the CPU and graphics cards, mostly. OTOH, I can attest that a lovely little Shuttle XPC with a big fat P4 will probably be enough to heat your cabin thru the coldest winter. Mine was like a hairdryer permanently on.
.sigs are for post^Hers.
I'd love opinions from those who have been in a similar situation.
Error: division by zero
Try looking at what they have here: solarpc.
They even have a complete turn-key squeak system (it's at the bottom of the page): here.
If you're just running 3-4 PCs, what's the point? Get a Belkin (cheaper) or APC (better Linux support) unit and get the same digits.
The person asking the question states that their desktop is sucking down 250W for PC plus monitor. My laptop (Fujitsu C2220 running Linux 2.4Ghz P4 and 512Mb) has a power supply rated at 100W and draws around 90W. Previously I've had Dell laptops that draw 60W. If you go get an Apple iBook instead then they draw only 45W.
Laptops make perfectly good computers, except as very high-end workstations/gaming machines. I have not owned a desktop machine for at least the last ten years. The small amount you are behind in terms of graphics processor or CPU is more than made up for by the ability to take the thing with you.
John.
not sure how much sun exposure you have avaliable, but a laptop plugged into one of these has to last a fair while.
:-)
might even come in handy in new york next time the power goes out.
Come on now, a true nerd would build a steam engine to run his generator. You clearly have some wood around. Sure the conversion efficiency is only 5%, but think of the nerd points you'd get for posting pictures of your steam-powered computer! ;) And, if you are really nerdy, you could even try for a Stirling engine, which could also be run in reverse to cool your CPU.
- can take it with you
- can pre-charge the batter elsewhere when possible
- has built-in "UPS"
- is specifically designed to use as little power as possible
- if you later get a generator for the rainy day, the battery gives you time to start the generator without hibernate/shutdown
- if you want the comfort of separate keyboard, bigger LCD, real mouse etc, you can still get them for laptop too (and getting that 2nd LCD may give you dual screen as a bonus) and still use less power
Whilst I can't say much about power usage I can say that a few months ago, I decided that my big old XP1600+ beast had to go and that a quieter, more bedroom friendly solution was required.
:)
I chose a laptop over a small, quiet PC mostly so I could take it to Tafe, Uni, LANs, etc on public transport, which doesn't sound like it will effect you much.
The point is, that it is quite possible to get a laptop to replace your desktop, especially since your computing power requirements seem to be similar to my own.
Personally, I managed to find a nice looking (Mac design clone) laptop with plenty of power for my needs. I was set back $2,600 Australian dollars for a Pentium M 1.5ghz, 512mb RAM, 40gb HDD, Geforce FX5200 Go and a 15.2" widescreen LCD (just as wide onscreen as my 17" CRT, slightly less tall.) Expansion wise, there is the one PCMCIA card and the internal MiniPCI slot which came with an 802.11b card inside.
My needs were also based around portability, and being a thin and light, this notebook weighs 2.7kgs. However, since you'll not likely be walking to the nearest LAN party from that location, I do think a laptop designed for good battery life will obviously use less power. Between the slower hard disk, powersaving, speedstepping CPU and powersaving motherboard, you could be using far less power than all but the best designed MiniPC. Another advantage to the laptop is that you get a few hours battery life in case your power dies or runs out of juice. Perhaps you could even take it out roaming your property if you're into that kind of thing.
Think I've rambled on a bit, but hope it's been helpful.
Seems you'd just need to stop by Home Depot and pick up about about 792 100' extension cords...
Solar power is generated and stored as direct current. In order to use a desktop system, you will need to convert to AC, so that the computer's power supply can convert it back down to the proper DC voltages. This is a wasteful process.
If you start with a laptop, preferably one whose input voltage is the same, or lower, than the voltage of your storage cells, you will make a more efficient use of your power system.
-Chris
-- This sig is only a test. If this were a real sig it would say something witty. --
...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
.
-- I wonder which will go down in history as the bigger failure: the War on Drugs or the War on Filesharing
I'm not sure if this will produce better power savings than a decent laptop, but it should save some 30% on power if you are going to use a PC.
I assume that you use solar power to charge up 12v batteries. Running that power through an inverter only for it to eventually get converted back to DC is hugely wasteful for a variety of reasons(A horrible power factor being one of them).
I just googled around, and found this page with a variety of DC/DC PC Power supplies, with a variety of supported voltages.
Now that I think about it, if you have the capability to supply the power supply more than 12 volts(ie: 24 or 48 volts), then that will probably improve your wattage even more(as well as improve your stability if your power is "dirty").
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...
— darco
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...
A word about laptops. Most of them have two modes they operate in. While running off internal power, they run in a low power mode. This many times slows the CPU down and dims the display. Also while in battery mode the fan will run on various speeds on demand.
When they are plugged in they speed the CPU back up and brighten the display - consuming more power since it is available. I think I would probably recommend a laptop, and a few spare batteries. Then you can charge on someone else's power and bring it back home with you.
Since your laptop will use less power when running off battery you should always use your laptop on battery power. Then when you shut it off you should charge the batteries. Make sure you get a laptop with two bays.
If you go with a PC get a variable speed CPU fan with a sensor. Then it can slow down when it is not needed, saving you some juice. Since I am assuming you would be building your own system then evaluate the watt consumption of each component, and add it up getting a good quality (expensive) power supply that meets your needs without exceeding them astronomically. When possible use one component instead of two (Optical drives, hard drives, memory modules, etc.) Two will consume more juice then one (obviously) when you can get a single hard drive that is big enough to do the job.
Display brightness has a huge impact on battery life. Whatever you go with make sure your display is as dim as possible. Put your computer in a dark room.
Also, don't run SETI@Home, GIMPS or one of those other background processing systems. Those really increase your machines power consumption, as do games!
Another must have would be a good UPS with a power conditioner. Brown outs are very damaging to your computer hardware. Not that I doubt your ability to build your own power grid, but wouldn't you hate to loose your PC because of a brown out?
"Anything is possible with enough programmers, time and pizza." (Substitute caffeine for time as needed.)
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
According to the insurance industry, 50% of all laptops get stolen.
According to the naturalists I know, grizzly bears are extremely smart, and damn near unstoppable when they want something.
When the grizzlies look in through that window and see that shiny new glowy-apple Powerbook, you *know* they're gonna want it.
Just be careful out there, is all...
Eloi, Eloi, lema sabachtani?
www.fogbound.net
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 would suggest starting with a rough power budget and working from both that and the monetary budget to figure the best trade off. Firstly do you really need a 1.4GHz athlon worth of power - no laptop today that is low power really has that.
For the VIA EPIA type desktop systems with the right LCD displays you can get the power down to about 55W including monitor (thats a real configuration EPIA M6000, Keycorp K57H + 12.1" TFT display, 256Mb, and a disk)
Laptops take you a little bit lower and you get the benefit of the battery being pre-fitted of course. That means looking for real low power laptops - crusoe, anataur, maybe PIII-M as well as making sure they have good power control in your favourite OS and preferably suspend to disk so you can kill the drain entirely when its off.
The CPU is critical, you can get "micro" P4 boxes but they still burn the same power, just in a smaller space. Large boxes can actually use less power because you need less fans!
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...
I'm in the process of building (year #5, woo-hoo!) a totally off-grid home in (almost) the middle of nowhere. I've gone through this already.
The short answer is if power is all you care about, a notebook is better. My Sony TR1A consumes 13 watts of AC when plugged in at full-tilt according to my power meter, and display-off sucks just 5 watts. However, I care about more than power, like uptime/durability, ability to use off-the-shelf components, and being able to support some modest external hardware, so the actual system that stays on 24/7 is a VIA Epia 533 MHz box. It takes about 11-12 watts but can peak around 24 watts or so, plus a 15-inch LCD monitor which is pretty much never on, but consumes 16 watts when it is; so you're looking at about 30 watts with one of the lowest power desktop configurations possible.
Other odds and ends consume power as well. Inkjet printers are great (Epson C82 sucks 1 watt in standby, about 5 when printing.) Larger ethernet hub-like things are about 5 watts as well. (That'd be hubs, terminal adapters, wireless routers. nearly everything in my 3com officeconnect stack at my real house is 5W per unit.)
As far as power budgets go, it's the time the devices on that really gets you. An 18W average setup running 24 hours a day is 432 watt-hours, almost half a kilowatt hour. While I have a pretty substantial solar array (1 KW at the moment) during the winter I'm going to see maybe 4Kw-hours per day, so I'm burning nearly 10% of my capacity on just one PC.
So.... you can use your kick-ass system if you want, and if you limit it to one hour a day v. 24 hours a day, you'd be ahead.
BTW, my losses on the total system aren't bad at all. Inverters and batteries are pretty efficient these days. I'd gladly accept a 50% loss on storage and conversion, however, if I got 50% efficiency out of the panels instead of the sub-20% that's typical of solar today.
As with most things marine, the 'marine' classification doubles the price instantly. Better look for traktion batteries that are used in golfcarts and forklifts etc.
As always with batteries, you pay for better quality, and just because lead ain't cheap either.
You are not supposed to run these dry too, discharging till 50% gives a much longer lifetime.
This space is intentionally staring blankly at you
- you have daylight
- the river is flowing
- there is a breeze
If all of the above fail, you have 2-8 hours of UPS power (depending on how big and how many UPSs you get), and 2-3 hours of battery in the laptop (make that 4-6 if you get a spare battery). You could make it through a frozen, long, dark, and still Alaskan night with that setup. You'll be set...and still nerdy/* oops I accidentally made a comment, sorry */
Not a bad idea!
Lets see, you should ideally keep your voltage drop under 5%, and this 250 Watt computer will draw about 2 amps of current.
120V * 95% = 114V, so we need to keep it above 114V, therefore we cant drop more than 6 volts total on the extension cords themselves (or 3 volts per wire, since the current is bidirectional.)
Thats 3V drop per wire at 2 Amps, so resistance of each 79,200 feet of wire should be lower than:
3V / 2A = 1.5 ohms
OK then.. we need three wires, each 79,200 feet and with less than 1.5 ohms per wire. That's 18.9 milliohms per thousand feet. Well, they do make wire that big, but you cant buy it at any Home Depot. So, we'll make the extension cords from the biggest wire you can get at Home Depot. Aluminum 4/0 wire, typically used for 200 amp service entrance condutors.
Unfortunately, using a single cable of 4/0 would drop almost 9 volts in each direction across this long a run at 2 amperes, so we're going to have to use ALL the conductors in an entire four conductor 4/0 cables for EACH conductor of your power cord to get the resistance low enough for your application. That will get us right at the maximum 6 volt drop at 79,200 feet out.
So, we need two 79,200 foot long 4/0 Aluminum SE-R cables, one cable for hot and one for neutral and we'll assume you'll drive a ground bar yourself since you're 15 miles from the 120V receptacle.
I think that cable is about $2.90 a foot last time I looked, so we need $459,360 worth of cabling. Probably best to buy in 1000 foot spools, but then you'll need hundreds of split bolt connectors and miles of electrical tape. (The good kind, not the cheapo electrical tape.)
Anyway, it is doable. Pulling the cable could be a real bitch. And keep in mind you're not allowed to suspend cables from trees anymore according to 2002 NEC. But then, you cant really use SE-R cable as outdoor extension cords, I'm just trying to keep this affordable for you.
Regards
I lived for eight years without electricity and then about 6 months on an off-the-grid power system. The laptops are definitely better: 1) Yes they take less power which will make a BIG difference. The numbers may not seem like it now, but when you actually get it set up, you may end up going for a few days of rain, clouds, etc. and then your battery bank can bottom out if you have too much to run and heaven knows that the computer is a necessity. 2) For some desktop power supplies you may need a true-sine inverter. Regular inverters that convert from DC to AC make a simulated sine wave out of the electricity, but its really more of a blockish wave. Inverters like the Prosine 1000W are more efficient and will run your desktop if you have the battery juice left, but they cost significantly more. 3) You're going to need that laptop for the car-trip back to civilization.....
If you can't say something nice, make sure you have something heavy to throw.
I have a "unabomber" shack out in the middle of nowhere, with no utilities to speak of. What you speak of is *very* doable with Solar power.
A few reflections on what I've learned.
* A PC, as you've learned, will usually consume in excess of 100W of power with the monitor on. Using aggressive settings on your power management software, a VIA EPIA motherboard, and a small LCD monitor you could probably get it around 50 watts. Such a machine is likely to feel slow.
* My Apple Powerbook is very solar-friendly. ~15W during heavy use.
* Try to get everything you need built-in. Things like PC Card devices or external storage really suck down power. The built in devices tend to be engineered for better power management profiles.
* If you find yourself needing to network, wire it. Wired networks suck less juice (at all points) than wireless. And it goes a lot faster.
* If you want to listen to music, budget that into your battery system. A laptop playing a huge MP3 playlist is never going to idle the processor down. Luckily batteries are relatively cheap, so adding just one more battery will add several hours to your runtime.
* If your situation is like mine and you will have a lot of little construction projects on your cabin while you're out there, my power use went WAAAY down when I switched from corded power tools to 18V Ryobi cordless tools. Charging the batteries did not appreciably diminish my reserves, the tools were almost as powerful as those they replaced, and they were much quieter and a joy to work with.
* Don't mess with car batteries. They are no good for this application. At the very least, look at RV/Marine Deep Cycle batteries (12V). Better yet, look at 6V Golf Cart batteries (which you pair up in series for 12V). The Golf Cart batteries will be the ones you want during those overcast weeks.
* Look into lighting, appliances, etc. that run directly off of 12VDC. There are many web sites out there that cater to hunting cabins, homesteaders, RV's, etc. You'll pay more for these appliances up front, but it is much more efficient to run most of your day to day stuff off 12VDC as you lose a lot in the inverter going up to 110VAC. The computer, however, should probably run off 110VAC if for no other reason to ensure that you're getting a steady clean feed from the inverter rather than from your PV panels & batteries, which may surge if the clouds suddenly part or what have you (the inverter will buffer this).
One thing you should probably think about, particularly considering your means of generating power (solar), is how you're going to jack this thing into your power system. You'll probably want a transformer to have some AC power in this cabin, but that's an extraordinarily inefficient way of using electricity.
If you go with a desktop computer, the power supply is going to expect AC input. The laptop, on the other hand, is going to have a power brick and a DC jack on the laptop.
For optimum power efficiency, you should get a laptop and then buy a 12V regulator, and a car-lighter type plug. The wattage is important, in terms of power consumption, but the voltage is equally so.
The HP/Compaq laptop we use onboard (its a ze1210, which is a basic consumer model of a year or so vintage -- runs Athlon with PowerNow). Using the DC adapter, the strain on the ship's battery is noticable, but not huge -- much less than the radar, for instance. When we run it off of one of our AC plugs (we only have one, and we almost *never* use it, the transformer usually stays disconnected), its a huge power drain -- more so than our radar array.
So, definately a laptop. Wire your cabin for DC. And consider looking at boating technology guides in general. They probably most closely approximate what you're trying to do.
-Shylock
Statistically speaking, there's a 99.998% chance that my IQ is higher than yours. Get over it.
Some numbers behind Kriston's post.
The "highly efficient" Luxeon star white led will produce a mighty 25lumens/watt.
A boring hardware store compact flourescent will produce 55lumens/watt or better.