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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."
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
There are many different alternatives. Yes, using a laptop is much more power-efficient, and you can get yourself power-adapters to convert DC to DC current to charge your laptop from a 12v battery car.
However, there is also a Mini-ITX form-factor system, to which you can find cases with built-in DC switching power supplies.
I think the solution is to stay native to DC current, and then convert as you see fit. So, all you need to have is a set of car batteries, connected to solar panels (for charging purposes), and you set-up some sort of power distribution & management system.
Get yourself an IBM Thinkpad X30 from the authorizes IBM Ebay store. These are heavily discounted (overstock) NEW laptops with a full warranty.I recommend these for several reasons:
Very durable, small -- won't take up that much space in your cabin
12" screen, more than adequate for general purpose computing, plus the smaller backlight mean considerable power savings in the long run.
Get yourself a couple of deep cycle marine batteries. 1 to use, the other being charged.
Do you want to build your own windmill? Looks like fun project.
P.S. I don't know how remote your cabin is, but if you get yourself a Proxim/Orinoco WiFi card (these have external antenna jacks) and build/buy from a ebay a hi gain 2.4 Ghz yagi antenna, you might be able to hit someone's WiFi AP. It's worth a shot/ fun to try.
If you do by any chance get WiFI with this setup, update your journal and let us. It would be cool to know how you accomplished it.
--
3-5 hr battery life depending on usage.
I chose laptop, even though I do 3D rendering. Everybody here has told you they use less power, yadda yadda yadda. One of the main reasons I went laptop is in consideration of a few things.
1.) I move about once a year. I'm sick of lugging my desktop around. When it goes extinct, that's it for desktops to me.
2.) I wanted an LCD that'd do 1600 by 1200, and the cheapest I've found those is $1,000. My laptop was only $700 on top of that. (Yay for Dell.)
3.) When it's time to replace my laptop, this one will still be useful. I have 4 towers at home that'll never see the light of day again, but the laptop I bought back in 99 is still finding use as a web terminal. (plus, selling them is easy.)
4.) I'm no longer sold on the upgradability factor. By the time mid-range processors are 4x what I currently have, I've saved up enough for a new laptop. I'm not the type to drop $500 in a vid card for a few extra FPS. (Lately I've been gaming on my Game Cube anyway.)
5.) Extra desk space. Need I say more?
My current desktop has been promoted to 'server', and I send it rendering jobs to do once in a while. Eventually I'm just going to hide it in a dark corner somewhere.
"Derp de derp."
I've been trying to minimize my power usage for some time and have measured several different systems using a watts up meter. (Unfortunately filtered through my memory)
I think the newer eden boards are a little bit better than the C3 in a ordinary mother board.
I think my G4 powerbook averages about ~15 watts as well. (Charging is closer to 30 watts.)
The important note is that the laptops include the LCD monitor whereas I was running the desktops headless.
Also to cut down on energy lossage with either the small desktop or the laptop try to get a DC to DC power supply. From what I've read an inverter will sap another 10 watts.
A friend has a place far from anything. Has phone, but no power.
6 solar panels -> a number of truck batteries (and charger) give him loads of power. 19" TV from the 80's works, usually, til midnight.
Gas for stove/fridge.
A couple of the panels are from the 70s. 80% of their orig efficiency.
His best investment of late was a new inverter. THOSE have gotten LOTS better in the last few years.
LCD absolutely.
Laptop has a UPS :)
Laptop can easily be rigged to take DC (48V or 24V solar is common). So why go from DC->AC->DC?
Also, you may not WANT the computing power of a full desktop.
Ideally, you could have an ARM computer or perhaps Intel/Apple might offer slower/lower power boxes. That said, are ibooks lowerpower than Intel boxes? The chips generally are.
You're absolutely right...and reminded me of something as well.
I was in Mexico this past summer and went on a a tour of the Mayan ruins at Coba with these guys. (highly recommended, BTW). On part of the tour, they had kids from a local village taking pictures of the tourists with a digital camera. Then, when we got back to the village you could buy a picture of yourself looking foolish.
The kids had a laptop and an inkjet photo printer inside a hut with a line run outside to a solar panel. These folks are way off the grid, but this seemed to be enough to run not only the laptop but the printer as well. Of course, it probably didn't do much good at night but is worked fine for them during the day.
If anybody else has seen this and taken a picture, I would love to have a copy. My technology failed me that day. (/hangs geek head in shame)
The trouble with that is the a Transmeta runs about 1/5th the speed of the equivalent Intel, and the newer Intel processors use less power.
Transmeta is complete crapola.
A bunch of solar panels, a few voltage rectifiers, an array of deep cycle marine batteries and most importantly a DC to DC power conditioner. (This will stablize your DC out from your battery array.
Get a laptop with a known good DC input voltage. (12-16 volts DC) and plan your system accordingly. (Say, running 24 VDC out from the battery arrays, conditioned down to whatever you need.)
Invest in some superbright white LEDs, a power bus and some other goodies and you have light with your computer.
Just don't plan to run any heavy appliances off the system.
You should design the system to cover all these angles by a factor or four, depending how reliable you want it. (Multiple factors for cloudy days, taking into account how many batteries there are to charge. Multiple factors for how many days you would want to be able to run laptop/lights for without recharging, etc.)
- 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 */
Actually, Li-Ions are very efficient when it comes to charging and discharging. I think the numbers were over 90% when I last checked them.
Laptops get hot when plugged in because of cheap regulator circuitry at the power input. Remember, there is no incentive to be frugal with power there because you are plugged in and have lots of chunky KWH coming out of the wall. My Powerbook gets very warm on the rear right corner, where the power cord plugs in, when it is plugged in. Definitely a voltage regulator module (VRM) there.
The actual charging process is very efficient, however.
Lots of people use tech much further off of the road than fifteen miles. If you are using a gas generator, even a small one, will power a few computers easily.
Laptops are great. I used one all thru university when I was living out of a tent. The worst thing that happened was getting frostbite while typing in my sleeping bag. Their only downfall is breakablility. Mine made it thru school to die a few days after completing my classes.
If anything, your biggest challenge is connectivity. For that you will need a satellite system and those take power, But again, a decent generator will power all that stuff and leave plenty extra for a fridge or other heavy device.
Good luck! Invest in a good inverter.
I got AC power not long ago but lived thru a couple years of "self generation of household power." I am in the mountains of Colorado. This is a situation where nomenclature such as generators, power inverters, DC to DC converters, solar cells, storage batteries and stuff will soon become everyday terms.
I would suggest that for electronic devices, stay as close to DC as you can, meaning use electronic devices intended for battery power. It is far easier (and safer due to transients) to use solar cells to keep battery systems charged than using inverters powered by generators to power devices.
I suggest going the laptop route and find yourself a local electronic engineer who (like myself) has been this route before.
Enjoy the new place !
TG
but they basically take the power in and put it right to the motherboard and components.
This is incorrect. Standard computers use 12v, 5v, 3.3v, -5v, and -12v power. 5v and 3.3v supply the majority of the power used. Additionally the 12v as supplied by cars and boats is not 12v, it can be anywhere from 10.5v (mostly dead) to 14.5v (chargeing). 12.66v is the actuall full charge potential of a lead acid battery. The power from an engine altenator is also not nearly clean enough for use in a computer.
A 12VDC power supply as discussed by the parent is a DC-DC converter. Typically the DC input will be inverted (converted into AC) so that a transformer can be used to generate the various required voltages. After the transformer the power supply is very similar to standard switching power supply found in computers. A good DC-DC power supply will be slightly better then an inverte and standard power supply. Typically either will be equally efficient.
A car is a really terrible generator. Most have trouble keeping their own batteries charged. An inexpensive generator will do far better.
The original poster should really figure out what they plan to do for power first. Depending on the power source they may not have to compromise.
Solar cells sound great in theory, but in practice leave a lot to be desired. Especially if the cabin is not located in a desert with lots of sun. Even if sun is plentifull it is hard to show that solar cells plus a bank of batteries are more environmentally friendly then an old fashioned disel generator running on dead dinosaurs. A properly installed generator running on biodisel with heat recapture, for hot water and heating, would be better. Although expensive a fuel cell generator (as posted elsewhere) is also worth looking at. Again heat recapture can be used. If the fuel cell is the propane type, the same propane can be used for cooking, refrigeration, and additional heating. Hydro is also worth looking into if there is water nearby. Bonus points for useing a windmill to pump water back up to the resevior for reuse.
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).
.5 amps" and I sigh.)
Both satisfied by VIA EPIA and Procase 12V DC-DC converter board (included in their Mini-ITX cases). I purchased a couple of these to play with in designing an outdoor router. (One with a lot more oomph than the commercial alternative, the routerboard)
The DC-DC board presents at one end a 12V 4.5A input, and at the other an ATX power connector and power for 3-4 peripherals (in my case, only one is used to power an IDE-CF adapter)
The only great problem I have is with 12V 5A power supplies - they're damn near impossible to find! (guys at Dick Smith say, "you mean
I too am very interested in having a solar-powered home, and have slowly accumulated much of the necessary equipment over the past few years (solar panels, large good quality near sine-wave inverter, batteries, charge controllers, etc.)
.80 = 6.4KWH per day (effective)
One of the things that you'll pick-up along the way, if you're serious about solar, is the 'Brand' digital power meter. See model 4-1850 here: http://www.brandelectronics.com/meters.html#table This device will tell you instantaneous as well as accumulated power use for any AC-powered device in your home, and is an invaluable aid to determining what system capacity you will need. Highly recommended.
As far as laptops go, my experience is that they use dramatically less power than their desktop counterparts. My DELL Inspiron 8100, which is getting a bit old now but for the purpose of discussion, typically draws 20-40 watts, depending on if the system is running and/or the batteries are charging. Once the batteries are charged, the system will run and the batteries will stay topped-off with less than 25 watt draw.
So, if you assume a 10 hour work day, you have something like:
Laptop: 25W * 10H = 250WH/day
Desktop: 250W * 10H = 2500WH/day (2.5KWH/day)
Note: WH is a Watt-Hour
That's a very big difference when it comes to generating solar power. I don't know where you are located, so I can't tell how many 'solar hours' you average per day in your locality (how many equivalent full-sun-hours you receive per day). Where I live, near Los Angeles, we average something like 5.0 solar hours per day. So, two 100W solar panels will produce:
2 * 100W * 5.0H = 1,000WH
If you live on the east coast, the average number of solar hours you receive will be significantly less than 5.0. A map like this http://www.solarseller.com/solar_insolation_maps_a nd_chart.htm will give you a crude idea about your own locality (but local conditions can vary greatly, depending on cloud cover, trees, etc.)
By the time people go around their homes and add-up the total number of watt-hours their individual appliances use they usually end-up realizing that they need a system substantially larger than two 100 watt panels. Most systems generate approximately 1.5 to 2.5 KW of power (instantaneous), before system losses (such as conversion of DC power to AC in the inverter, cabling losses, losses in charging/discharging batteries, etc.). So, for example, if your system generates 2.0KW and you average 4.0 solar hours per day then you would average:
2.0KW * 4.0H = 8.0KWH (kilo-watt hours) per day
In reality many people estimate that only 80% of the theoretical power that can be generated by the solar (photovoltaic) panels will actually be useable, so:
8.0KWH *
This is a significant investment, and your 'sizing' decision should revolve around all of your needs (not just your PC) plus a little extra for growth. As you can see, 2.5KWH would probably be a substantial part of your energy 'diet' (compared to 250WH for a laptop).
Many, many web sites dealing with solar and other forms of alternative power have cropped-up over the past few years. I like the prices and service that I've received here: http://www.partsonsale.com/slrelecar.html#anchor42 999
Either way, solar is still probably much cheaper than having the electric company bring power out to you (even if they can). 15 miles of cable will be VERY expensive. If you don't already know, check around because many states offer rebates and or other incentives for installing solar power. There's a lot to learn, and there are many ways go about planning your own set-up to match your needs.
One of the best resources for information is the venerable 'Home Power Magazine' (http://www.homepower.com). These folks are fantastic, and have been publishing a magazine for people who want to set-up their own 'home power' systems at least as far back as
A small system for powering a cabin can be had fairly cheaply - under $5000.00 for a decent system (a very decent system), if you install it yourself. Most of cost will be in the panels and batteries. You won't be able to run a washer/dryer or anything large like that, but if you set up LED lights or compact flourescents, you can have a nice solution for the cabin, to provide lighting, run a small TV or radio, maybe a few small RV/boat appliances (they make appliances specifically for RV's and boats that run off of 12 or 24 volts) - plus a laptop.
If you have steady wind, a small wind generator or two could be handy as well, as long as you are in a clearing or can get it above the treetop level (just make sure to ground it for lightening strikes).
If you just need some quick and cheap power for lighting, a small solar rig can be easily cobbled together from a small panel or two, one or two small old UPS batteries (like the small desktop UPSs use), a diode (for reverse current protection of the panel), and some wire plus a fuse. I built such a small rig to run a flourescent light in my tent at Burning Man this year - ran great at night, charged it during the day - didn't spend a dime on the batteries, the panel was from a yard sale (think I spent $10.00 on it or something).
Reason is the Path to God - Anon
Don't get "marine" batteries, and forget about bass boaters. They don't know jack about DC power. As the owner of a sailboat, I can tell you that golf cart batteries are cheaper and better than marine deep cycle batteries. If you really care, the AGM (a glass mat) or gel batteries are the best, but you would want to work out the cost per amp hour over the life of the battery and I think that the golf cart batteries might still be cheaper, since the gel's and AGMs are really picky about the charger used. They are also more resilient. You'll probably want to chuck the inverter and get one of the 12v lighter plug adapters (the adapters for airlines) for the laptop. Otherwise you'ld need an inverter from dc that would go through the laptop ac adapter that would take it back to ac. Not very efficient.
Then you can use solar/wind/diesel to charge the batteries. It works on sailboats, and you won't have the same space/weight constraints so you should be fine. (Also, get a centrino based laptop, I believe they are more power efficient...)
Don't be so quick to dismiss wood! Take one 30' coil of steel tubing (auto store), used weed eater two stroke engine, make a bash valve, injector, and condensor (water cooled) and a few hours of lathe and mill work and some brazing. Add a used alternator, and some controls and add a deep cycle battery and a 1000W or so inverter ($100 online). Google will reveal the details. Now a cord of wood will not only keep you warm all winter but also run your PC, lights and a small fridge/freezer. Much more sensible than a solar/wind system :) :(
If I wasn't so dang busy helping my wife get her business off the ground I'd have mine built by now
90% of the wealth is in 2% of the pockets. Bummer to be in the majority.
This is a no brainer. Go with a laptop. Laptops are designed to use minimal power. Mine only consumes 75W max from the wall. Much less if it's not charging a bettery, backlight turned down, not burning a CD, etc. Use a wired net connection since wireless cards use a lot of power. Don't forget if your power browns out or fails you're still golden if your battery is charged.
Another way to look at it, is to optimize power for the other electrical appliances/gadgets you'll be using as well. Energy saving fluoroscent lighting, washing machines, smaller TVs, etc can all free up up more juice for your laptop. Oh yeah....and I'd go with a laptop. Especially a Centrino based one. They have really good power utilization.....some laptops can run 6 hrs at a stretch.