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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 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.
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.
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.
The laptop has power conserving options and its own battery source. The laptop will give you more flexibility. Plus, you can take it on business trips to meet with other hill billies in the co-op. Imagine the waste of powering the desktop on and off.
Plus, Thoreau, you can take a bag of batteries over to your moms there and charge them up.
What will you use the computer for out there? Reply.
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.
Some of us most cope with living in Rural-est America.
.30-30. Dialing 911 may disappoint.
I'd personally like to thank everyone else for voluntarily incarcerating themselves in a large city.
Thanks.
A laptop is the way to go. Just make sure it has firewire/USB2.0, so you can use external DVD and harddrives. If you pound on it all day, you'll also want a real keyboard and mouse.
BTW, get a good 12 GA or
- 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.
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. --
I use a Hush PC (www.hushtechnologies.com) and it works perfectly for what I need. It's a desktop. I don't even live in the boonies! But rather, in a very small Honolulu apartment. Since the apartment is small, I needed a computer that I could put in the bedroom without annoying my girlfriend (or me). And, since I'm a Gentoo geek, it's constantly doing something, so I didn't just want to turn it off. My 19 inch LCD monitor and Hush together take less than 100 watts, combined, maximum (that's the maximum ability of the two power supplies. It's a modern computer -- 120GB HD, 512MB RAM in my configuration. Slightly on the slow side, but hey, the advantages, you can listen to the birds and forest sounds without the din of a loud computer, and it fits within your power requirements.
Erik
They also have sensational battery life. My old g3 pizmo w/ 2 batteries would last 8 continuous hours of word processing. And would do a week business trip of casual use without recharging. My TiBook and iBook get about 3 hours of casual use (w/ airport).
If you have no religious preferences about computing then the Apple will give better power performance. The G3 iBooks are coming in cheap now. Especially, refurbed. Then you can save money for the solar setup that is going to hurt more.
Consider a lot of the same factors for desktop or laptop.
If you can sacrifice a little performance, you will find that a system that uses a Transmeta Crusoe or a VIA Eden CPU will consume far less power than anything from Intel or AMD. There are a few nice Transmeta based laptops.
Both provide good x86 instructions and run XP or linux fine.
As well, going with a small (15"-17") LCD will be a big power saver for a desktop over a traditional CRT.
Use a lower RPM disk, or a laptop drive in your desktop.
On a laptop, if you can live with dual scan it uses less power than active matrix. If you can find an "organic" LCD like the one in the Gameboy Advance, they use the least power of any acceptable display technology I've seen.
Also don't forget to optimize those energy savings times to get the components to "sleep" after just a short idle time.
Cheers!
~8^]
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
Instead, get a half dozen car batteries for the same price. You'll get about a day's worth of power (IE, 24 hours).
Err, carr batteries are designed for short heavy loads - starting your car in the winter. You can run them all the way down and recharge them a couple times but then they're cooked. Substitute "marine" deep cycle batteries - the ones people use to power bass boats - same 12v lead/acid battery but the plates inside are designed for complete discharge.
At the bottom of the endless pile of paper work which characterizes all regulation lies a gun.
Alan Greenspan
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.)
Laptop Pros:
1) A very small form factor that is easily portable, and easily stored out of the way. My experiences with cabins say that this is good.
2) The built in battery is a very effective UPS which is good when you are dealing with unreliable power sources (solar, etc).
Laptop Cons:
However, laptops are designed to be power efficient when running on battery, not when plugged into the wall. Depending on exactly how the battery charging works, they could be very inefficient when running on external power (like some UPS's are).
For example, I know the external power supplies draw some power whenever they are plugged in, not just when they are connected to a laptop.
plus-good, double-plus-good
Someone brought in a current meter in my computer hardware class. A p-133 PC with HD, Nic, vga, CD, and floppy drew 40 watts. Throw in a 14" crt monitor and it drew nearly 175 watts. So a normal PC wouldn't be that bad, just go to a LCD display.
If this is a cabin, you're probably only going to be there on the occasional weekend. In which case get yourself a laptop and a gasoline generator. You can probably get by with one of the dinky little Honda EU1000's. Whisper quiet, stingy on gas and should run your laptop, charge your cell phone battery, a couple lights, maybe a portable TV and small frig (maybe not all at the same time). It won't run a full size frig or electric heater, but it's easy to carry. Around 800 dollars. If you need more power, a Generac 4,000 watt is quiet, produces clean power and should run most of the weekend on 5-8 gallons of gas (depending on usage). Lot cheaper than Honda's for the same amount of power and that will run a full size refrigerator, heater, TV, satellite receiver, whatever you want. Home Despot, around $750.00. It weighs about 150 lbs (on wheels), so you'll need a pickup or small trailer to haul it back and forth.
With any generator you have to look at the sustained wattage and surge wattage. Honda tends to advertise their surge wattage, which a generator can't maintain very long.
If you ever decide to live up there permanently, you'll want to look at either a big solar or combo solar/wind system. Figure on 15 to 20 thousand depending on the wattage you need. If you have a stream or spring, you're golden. Hydro electric is the cheapest and best, until the creek runs dry.
That's our life, the big wheel of shit. - The Fat Man, Blue Tango Salvage
Don't forget to mention how this is accomplished. You will need what is called a DC-DC converter. They sell universal ones at retail outlets where you just pick which connector your laptop uses. It is ment to be powered off 12V DC (like a car or marine battery or alternator) and basically cleans up the source, and splits it into 12v,5v, and 3.3v rails.
If you use solar pannels with the standard laptop power supply, you are seriously wasting lots of electricity in the form of heat.
Also watch out. if you are going to go all DC (ie, no power inverters for AC) then you will want to make sure to keep your power cables from the pannel to the house short and thick. low voltage DC current isn't like high volt AC. Longer and thinner cables won't carry your electricity very well and will greatly reduce the wattage your solar pannels will provide to you.
Two infinite things: your stupidity and mine. But I'm not sure about the latter. If my sig offends you, I'm sorry.
Also if there's already some sort of battery or capacitor in the solar power setup don't even run teh laptop with the battery in - why waste any power charging batteries - just put them in every week or so to top off.
Same goes for anything else, anything that runs on DC power you should hardwire to avoid the redundant conversions.
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!
Not the fastest, but reasonable performance. I don't know how much electricity it uses, can't be much, makes little noise and barely even gets warm.
HenryJamesFeltus.com
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.
You said "Err, carr batteries are designed for short heavy loads"
Being a person who has worked with many lead acid batteries, I have to disagree with you. A lead acid battery is at its most efficient when the load is the least. Under very heavy loads a lead acid battery will generate high heat and release alot of hydrogen. The only components that are really suited for short heavy loads are capacitors and inductors. The reason that you can use your car battery to start your car without damaging it is because the duration of the high load is very short.
I agree that lead acid batteries can become damaged if they are discharged to depletion, but if you only discharge about half the capacity of the battery (and then fully recharge it), it should run for a very long time before replacement is necessary.
Suddenly, the hairy finger of a familiar monkey tapped me on the shoulder. It was time.--G. T.
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
1. Use a laptop. A real one. The cheap desktop replacement with p4 and everything suck well over 100W. Get a light weigth laptop. You should be able to get something with p3-m that draws an average of less then 50W. I personnaly love my Thinkpad X20.
2. Use deep-cycle battery (used in boats and some RVs) they last 2-5x longer (both in number of months you can use them and in how long you can suck power from them before they're fully discharged) then car batteries so you won't need to replace them every 3-6 months.
3. Get a good marine-grade charger while you're at it. And, also, marine wind generator might be an option, especially if you're on top of a hill or on the shore or if there's a strong dominant wind. When a good wind is blowing they generate a lot more then a solar panel.
4. Try and find a AC/DC power adapter such as the IBM 22P9010 Thinkpad 72W AC/DC Combo Adapter. This will get rid of the huge inefficiency of running the power through an inverter to make AC to then have a transformer turn it back into DC. Note that the watt rating is because this adapter is good with ALL thinkpads.
5. Your lighting will suck more power then your computer anyways, invest in the most power saving DC lighting you can get, see a marine or RV dealer.
6. Pumps (say, for pressurized water) will drain your battery really fast. Air contitioner/heater, electric pipe heater (ie: you use a well that is not under the house and the pipe is not buried deep enough or pump from a lake and you're in a cold climate) will require a genset.
That's what I can think of, on top of my head. Basically, the Marine electricity folks have the most experience with clean DC electrical system, mostly from cruising sailing boats. RVs are also ok but they rely heavily on genset so they get away with 1+ kW/h of consumptions.
Also, when you switch to DC power, what you really want is an amp meter on the main circuit to know just how much you're drawing and a volt-meter on each battery bank(s) to know the charge level.
A marine deep cycle usually provides 90 Amps/Hr. @ ~14VDC nominal for 1 Hr. Full discharge is about 11.5VDC (this would kill a car battery in a few cycles) and full charge is around 15VDC. A 48W constant DC draw @ 12V is 4 Amps/Hr.
Try this link and see if they will let you be a test Guinea Pig: http://www.sta.com.au. Their dye sensitive cells are suppose to be cheaper than commercial power. They are in the testing phase.
Also try the Valence Technology Lithium Ion battery for extended up time.
If those doen't work out, I'd get a bicycle with a generator.
Somebody else mentioned that laptops usually have DC going into them (external converter). A very few take DC direct in, and that would be bad for you. If you can do direct DC->DC conversion to whatever your (external) adapter puts out, you'll save a good bit on power conversion.
Yes, a desktop would be more expandable, but just how much expandability do you really need? If you're preparing to live 15MI from powered civilization, then I'd have to presume that you're going for a vaguely minimalist lifestyle. If that's the case, make due with what you get on a laptop.
I'm still using a P3/450. Other than doing thing like recompiling the kernel, I really don't miss the extra CPU. A voodo3 gives me all of the graphics I need. You'd have to look pretty hard for a new laptop that doesn't give you more power than that, today.
One thing that is useful on a laptop is an external keyboard and mouse. Most laptops can also take an external display, so you can also add a nice 17"LCD if you'd like.
Free Software: Like love, it grows best when given away.
Gasoline is costly.
[warning, american centric prices]
Is Gasoline costly, vs power directly from the grid? Not to put to fine a point on it, but based on my observations.... the fuel bill for something like fuel oil, which is diecel #2 floats at $1.50 a gal... and is also on par with what I use, propane heat also at about $1.50 a gal.
I burn roughly 100 gal a year at a cost of $150 for heat and stove. While I don't have an accurate price estimate of what I was consuming with electrisity for the heaters... but needless to say it was a hell of alot more then $12.50 a month average. Friends I know have oil heat burn a similar amount.
I don't have much in the way of experence with generating electristy with a gas (petrol, diecel, propane/methaine) powered generator, but based under the assumption that it's cheeper to heat via gas... depending on how efficent the generator is it might actually cost less to heat by gas.
I had planed to research this for friends / family who live back east, where the cost of electric is extraordenary and depend on AC in the summer to not cook.
There is no sanctuary. There is no sanctuary. SHUT UP! There is no shut up. There is no shut up.
If you decide to go the route of the desktop for this project (which is possible, but I still recommend a laptop with DC/DC power adapter) then here is what you need to get:
Start with an ATX or microATX case. If you choose microATX, make sure that it accepts a normal ATX power supply. You can buy DC-DC ATX power supplies online (but microATX ones are harder to find) As long as your microATX case takes the ATX PSU (i have one i bought for $30 online that does just this, I think enlight's microATX also does it) then purchase an ATX DC-DC power supply online. 180 or 200W should be enough. You may also want to consider a Shuttle Cube barebones with nForce2 motherboard. In this case you could probably still use the DC/DC power supply, but you would have to have it sitting external to the unit (in the back somewhere) Maybe paint it black so it doesn't look ugly, or put it in some sort of asthetically pleasing case of your choice.
- Don't go for the highest power CPU and video card. Select either AthlonXP (barton core only), Duron (latest core), Pentium3, or if you can get your hands on it, Pentium M processor. DO NOT buy a pentium 4 or P4 based Celeron you will seriously regret it. the newer AMD AthlonXP Barton cores have very good power saving features and if you don't overclock it, you will not be in so much hurt. In fact, it is possible with newer motherboards to underclock the chip and under volt it. I would definately consider doing this once you get your system up and running for the long run.
- Select a motherboard for your processor. if you are going with athlonXP or duron, I would recommend the nForce2 Ultra motherboard. Get the one with integrated video. You don't want a seperate video card taking up extra power. The integrated video is decent 3D with quality similar to Geforce MX series. NForce2 Ultra's dual channel memory controller should HELP make up for some slowdowns get for having a lower powered/underclocked CPU.
- With the nforce board (or other comparable board) you won't need addon cards like NIC or Sound. (hopefully your motherboard will be supported under linux with sound and NIC drivers) if you do need addon cards, use only your absolute minimum requirements.
- Buy LARGE 5400RPM hard drives. Don't go for 7200RPM, and don't buy small ones. If you want 160 gigs, don't go out and buy 4x 40GB drives. Just buy one. if a RAID array is required, then still try to stick with 5400RPM drives as large as possible. The larger your drive the fewer you will require in your system. Don't use a buncha extra drives you have laying around. Spend extra on this project and do it right with a single drive solution.
- This next step is a little harder to do with commodity equipment, but is possible. Buy fans that will adjust their speed depending on temperature. Most "temperature sensitive" fans are tuned so that in any real world circumstance, they are either full time full speed, or full time minimum speed. You won't find many fans that are tuned so they slow down when your PC sleeps and speed up when the temp rises due to CPU load. You need seperate logic to do such things. The simplest way to go is with a "fan bus" which has manual knobs on the front of the computer. You turn the fans down as low as they go when you get up and leave your PC idle. AVOID fans smaller than 80mm like the plague. Don't put active cooling on your motherboard chipset, insted opt for a larger heatsink on the northbridge, with quality mounting and quality heatsink grease. Also, opt for expensive but massive and large heatsinks for the CPU. Don't even bother with a 60mm heatsink, as it will cost you in the long run. I personally use 80x80mm alpha heatsinks (with copper inlay) with a 92mm fan that has a 92-> 80mm plastic fan "adapter" cone. This way you can buy LOW SPEED 92mm fan that uses negligable electricity rather than buying high powered high speed 60mm fans. Consider using a single 120MM case fan in the front of the PC running at 5 or 7 volts (you can do this by changing the wires on the MO
Two infinite things: your stupidity and mine. But I'm not sure about the latter. If my sig offends you, I'm sorry.
D-I-E-S-E-L
He committed suicide because idiots spelled his name wrong.
That was classic intercourse!
Keep in mind that while chemical-to-heat reactions can be made over 90% efficient, chemical-to-heat-to-motion reactions in a typical portable generator are more comparable to car engines - 30-40% efficient (non-portable large-scale multi-stage turbine generators can do more like 60-70%). If you're storing the resulting electricity in a lead-acid battery, that's only 70% efficient.
Assume that you have an average 35%-efficiency generator charging lead-acid batteries. That system has an efficiency of 24%.
Given that gasoline stores about 130 megajoules of energy per gallon, and you can recover 31MJ of that (same as 8.61kWh), and it costs you $1.50, then the break-even point is $1.50/8.61 (or $.174) per kWh. If you're not charging batteries, then the break-even point is $.118/kWh.
For me at least, the grid is significantly cheaper. As it should be.
Also, if you need the waste heat from the generator anyway (and can rig up a way to exchange it without dying from carbon monoxide), that could make generation a lot more worthwhile.
I live in Australia, and moved from a capital city to a place that was off the grid, uses gas cylinders for hot water, and water tanks & a dam for drinking.
I am a contract programmer.
Laptop is definately much less power hungry - a lot of effort goes into customising the system to be low power friendly. Also, your switch mode transformer and batteries will act like a power conditioner and UPS rolled into one - this is important.
With the solar system, it all depends on your budget - get the best you can afford. I have 1.8 Kw (nominal) of solar panels, and a series of 6 deep cycle batteries (6000 AmpHours). When building the system, it is important that you don't cycle the batteries too hard - day to day you should only be using 10% or so of your stored power. If you use much more, the lifespan of the batteries drop considerably. I also recommend a good inverter - I use Selectronics (a high quality local brand). For internet access, I use satellite down, and modem up (I have two phone lines, but I am too far away to get ADSL). In the states, DirecTV has similar systems - not sure of local pricing.
Just my 2c worth...
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.
Check out Ken Kifer's bicycle touring experience with a solar powered laptop.
-biff
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.
Bringing the information to a thread more specific to the subject, i'd like to inform that #7806067 previously posted a link to a interesting Battery FAQ
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.
Some questions:
1: How long will you be in "the boonies"
2: Is Internet connectivity a necessity, or nicety?
2a: Is dial-up satisfactory?
3: Can battery or otherwise low-wattage/DC solutions do the job, or do you need AC power?
If you take into consideration that you'll be in an apparently stripped-down environment, you might be happier and more productive in the long run if you have a stripped-down computer to match. I lived in the country with a radically altered computer situation, with 28.8 the absolute BEST I could do, without springing for ISDN, and I found that a powerful PDA - as long as it had a typeable surface was enough to suit my needs. However, I didn't need to compile anything, host any databases, or do any kind of "9 to 5" (as you mention) thing with that setup.
Diesel (generator) is a great idea. Is it practical for your situation? Solar is also a worthy power factor to consider, but not starting in January :), nor February, and questionably March, as well. Pedal-power works in any light condition, and since you're in the country, your access to citified diversion is limited as well, so maybe a little treadmill or excercycle computing would probably benefit you. (As it would any geek!!
My suggestions:
8/16 Bit Wonder of your choice & TV (portable, handheld, console, whatever - can be modified to run on straight DC)
2nd/3rd Generation Palm/WinCE Device
Apple Newton 130 or eMate 300 at minimum,preferably 2100/2000U (WiFi/MP3/web server/etc. capability plus EXCELLENT power usage)
Psion or compatible device (Has keyboard and multi-tone display)
Modern, power-concious laptop (used Transmeta-powered devices are in the stream, now)
Standard, off the shelf laptop. IBM or Toshiba, if you're going to be out there for a while! (Maybe a Toughbook?)
I dunno.