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Solar Cells For Laptops?
P-Weasel hooked us up with linkage to a solar device designed to work with laptops. It's about the right size, and if you happen to ever find yourself outside, this may be just the ticket to circumventing those ridiculously short battery lives on those P3 laptops ;)
Laptops will run for hours on these 50 lb things. Of course, FUCKING LAPTOPS NEVER SEEM TO HAVE 12V POWER INPUTS. It's always 15V or 18V. Why are they doing this? It makes it harder to run laptops off of a car. My solution was to install a 300W (don't freak, the inverter won't draw 300W unless it needs to) inverter in my car, then just plug the laptop AC supply into the inverter. But this *must* wast some efficiency.
Hmm, let's see...
Maybe you want to code?
Or write a paper?
Maybe you can go into civilization occasionally, to purchase software on CD-ROMs?
I used computers just fine before I ever knew "net access" existed. I could play games, type in programs, and generally do anything I wanted to on my computer.
Also, I didn't know about *computers* when I lived in the mountains as a child, but when I came back to visit, I'm sure the people in the local commune were very glad they could run their laptop off of solar power. (and yes, there are places where people have phones, but aren't on the grid, too) I know they were using the laptop to teach the kids, and probably for other uses, besides.
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pb Reply or e-mail; don't vaguely moderate.
pb Reply or e-mail; don't vaguely moderate.
His math is correct. Watts are a measurement of energy flow (joules per second). Multiplying watts by a time period gives you a measurement of regular energy again. In the case of the example laptop battery, that measurement is in watt-hours, a unit that's easier to use in the sort of calculations he's doing. The battery has a total energy of 79WHr. If it takes 3.5 hours to drain it, that gives a constant draw of 22.6W. If the solar panel provides 13.8W, that reduces draw on the battery to 8.8W, greatly extending its runtime. (Yes, this assumes optimum conditions. I think we all realize that solar panels don't work in the dark.)
No, you can't run an Inspiron 7500 completely on solar power. You can, however, run the laptop for a much longer period of time than the battery alone will give you. You can also recharge the battery while the laptop sits unused. For someone away from a power source for an extended time, solar cells can provide a means to keep a laptop working.
--Phil (Heck, the thing would be good just for an afternoon coding in the park.)
355/113 -- Not the famous irrational number PI, but an incredible simulation!
Every discussion involving solar energy always brings out the guys saying how impractical it is to have huge panels strapped to your car / body, and how solar panels don't have enough juice to run a TV all day, and how your device will shut down when a cloud comes by.
Duh.
Solar power application today is always about charging batteries, and it's always about low-power requirements in a place where more conventional power is not available.
David E. Weekly
David E. Weekly
Code / Think / Teach / Learn
h4x0r for
Nice idea, but completely impractical, especially considering most people use their laptops inside (which is low-lighting conditions, btw). When was the last time you saw a system admin outside? Well... back in '83 we saw one go outside on a sunny day... poor bastard turned to dust, and 'ver since no sysadmin has gone outside.
Soon as I have the $400 extra.
I'm already ordering my electricity from other side of the country to have it windmilled rather than fissioned. I have a laptop that I use as MP3 player outside, and love to sit out and compute in sunny days - it's just hard, not impossible, to see the screen. Just take a good position. Battery limit of 2 hours is really lame. Lack of net sucks, but I might be able to run ethernet to the roof terrace...
This is News for Nerds. This is Stuff that matters - for me.
However, I'm waiting more anxiously to have a Crusoe wearable with wireless Net. And easing the restrictions of computer usage on flights.
I think, therefore thoughts exist. Ego is just an impression.
of these - enough power for a notebook, wireless, and more. Solar may be neat but it just can't compete with burning refined dinosaur era hydrocarbons (sunlight energy from long ago locked up in chemical form). Of course, there's only a limited supply of it left....hmmmm.
try { do() || do_not(); } catch (JediException err) { yoda(err); }
Hmmm, usually batteries are rated in AmpHours, but I don't see why you can't just * by their rated V and use WattHours - a watthour is a unit of energy (why you electric bill is in WH), and batteries hold only so much energy. Power is energy / unit time. An amp = one coulumb / second. A stich in time saves nine. A nearby batt says 10.8V 4.05 Ah, or about 40Wh - it can crank out 10.8V at 8.1 Amp, 80Watts, for 1/2 hour = 40Wh; or it can pump 10.8V a 2.025Amps, 20Watts, for 2 hours again = 40Wh. Since the laptop can run about 2 hrs on this batt, it's drawing about 2 amps @ 10.8 V or about 20Watts, the solar panel can supply 13 watts so the battery only need to supply 7watts, or .7A at 10V to make up the diff, resulting in increased battery life of 5.7hrs, which is the same result gotten from: 40Wh / 7W = 5.7
YMMV
try { do() || do_not(); } catch (JediException err) { yoda(err); }
Posted on a Powerbook G3 running LinuxPPC2000
History has the relation to truth that theology has to religion-i.e. none to speak of. - Lazarus Long
I hear it can give you a nasty burn, but the screen isn't all that bright. What's the deal? Is it due to CRT X-ray emissions? (Mommy always warned us not to sit to close to the TV) Probably -- my friends always seem to have them when they come back from underdeveloped places, like St. Kitts or Mexico. I imagine they have a lot of older surplus monitors in those places.
My Sun does seem to run as hot as everyone says.
__________
If you can go to bed, knowing you did a valuable thing today, you're very lucky. If you can't... it's not bedtime
First, if you are comparing to wall power, then these are obviously a bad deal. Distributed energy is always a bad deal compared to existing wall power. That's because the utility has already made all the capital investments for you, and they get the best deals on long-term financing -- it's hard for an individual to do better, even with all those utility investments in nuclear.
But these are an outstanding deal if you live off-grid. They are convenient to move around, they have a cord so you can keep your laptop in the shade and the cells in the sun. Unfortunately, the level of ambient light even in the shade is too high to comfortably view a laptop screen. It takes some getting used to, especially during the middle of a sunny day.
Second, regarding solar power plants. $0.56/kWh is not "just on the edge" (edge = $0.03/kWh) and photovoltaics are the least likely technology to be used in a commercial powerplant, barring commercialization of that Australian guy's silicon wafer manufacturing improvements. Yes, it is true that efficiency and output are directly related to the amount of sunlight shining on the panels. However, they are inversely related to the temperature of the panel. The hotter they get, the worse they work.
I'm afraid you are also taking a bunch of disparate facts about the energy industry and taking them out of context here. The reason prices hit $6000/MWh several years ago was because of market speculation and a series of shady deals. It had nothing to do with the real cost of producing energy.
I am not trying to rain on anyone's parade, as I am in fact a die-hard renewables supporter -- I worked in the energy industry and I know how much we need cleaner technology. But there are many other emerging technologies which will change the industry drastically, much more so than photovoltaics. For instance, fuel cells - technology with a chance. Prototypes of fuel-cell powered laptops and cell phones exist, and will soon allow you to run your laptop 28 hours without "recharging". Not only that, but you'll probably able to carry around a couple of very small canisters of hydrogen or other fuel much more easily than toting batteries.
Now that is mobile computing.
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"If children weren't copyrighted, no one would have babies." -- Alex Eulenberg
It's like a giant, round fullbright pixel in the sky.
A few years ago, a company (name escapes me)sold a solar panel BookCover for the 1400. It wouldn't entirely power a 1400, but you could extend battery life a bit. You could also recharge the internal battery in about 6 hours (the battery gave about 2 hours of run time, if you were lucky). I never picked one up, and I can't find much about it on the WWW any more.
-jon
Remember Amalek.
The scary part is that he might not be joking. ;)
My journal has hot
Does anybody remember comapaq's method of obtaining energy from each keystroke on the keyboard? Any insights on what happened to that?
Wattage is NOT measured per second. It's a measure of POWER as in P=IV where I is current in Amps and V is voltage in... volts.
In addition, Amperage is NOT measured per second. Both are time insensitive measures!!
Dell lists their battery life in Watt * Hours and therefore, dividing X Watt * Hours by Y Watts results in X/Y Hours.
In addition, I specifically stated in my assumtions that the notebook has the battery IN at all times. It would be crazy not to have the battery in, as you mentioned above, which is why I never suggested you take it out!
Take some physics, take some circuits, and re-read my post (noting the battery, and my comment at the end that the calculations are based on the 13.8 Watt figure from the company and the lower end of Dell's estimate on battery life!!)
I would say IANAEE (I am not an electrical engineer) but oh wait, I do have a BSEE. Even if you discount the figures significantly for fluxuation in sunlight levels and optimism on Dell's part, your figure:
you might get, uhh.. 20 seconds of extra life per hour of use. With 30 flourescent lights shining on it.
is patently ridiculous.
- StaticLimit
The laughter thing has an easy fix - you have to put these things called "clothes" over yourself. Bob probably just assumed you already had them on.
These folks are just trying to unload stock after their solar-powered flashlight business tanked.
Next we'll see them unloading the flashlights as a means to light the solar panel.
But plenty expensive, too. Look into solar panels for RV's - many of these are quite large, and can be adapted easily. You will need a large voltage regulator and a battery bank as well - and if you are planning on running 110VAC, an inverter (many people just buy 12 or 24 volt appliances, instead). You can easily spend several 10's of thousands of dollars on a system.
Look into wind power options as well (if you have an ample breeze blowing). If you live near the border of Mexico (near a border town), sometimes resellers of solar solutions hang out on the US side (esp if there are RV camps near the border town).
Building a solar panel for heating water is almost trivial - a bit of copper pipe, some plywood and two by foors, and black paint (plus a sheet of glass) is about all you need. You can build a pretty good system to tie into your home heating system for less than $500 (and remember, you might be able to take a tax break as well).
Final note - it is possible to build a house and COOL it using a passive solar solution. The trick is the house has a large chimney which is heated by the sun. As the hot air rises, it draws in cooler air through the windows, or through vents with water evap pads (similar to a swamp cooler). Not great for places like Lousianna, but for desert areas without too much humidity, it is almost free cooling.
Reason is the Path to God - Anon
I've got an expedition model of this series that I purchased a few months ago. A bit pricey (around $400+ i think) and I haven't quite got it to go quite to the full rated spec of around 20 Watts, but the cell is supposed to be more efficient at higher ambient temperatures.
;)
:-)
With passive resistive loads I've seen as high as 16-17W (but on cold days as low as 10-13W!), but keep in mind if you run it through an inverter you are going to get some loss probably 2-3W. To bypass this problem I bought a 50 Watt zener diode at the rated voltage of the DC input (around 16V for my laptop). (Cost around $12 versus $75-$100 for an invertor). In my research I came across this site from which I learned that solar cells act like current sources, which is ideal for a zener diode. The diode essentially syphons off all the extra current your laptop uses, and since it is placed in parallel with your laptop it doesn't draw any power that your laptop can use. The zener also regulates the voltage fairly well. The 50W rating is necessary because there is no series limiting resistor and thus the zener should be able to sink twice the rated capacity of the solar panel (to be on the safe side, especially if you don't have a heat sink
I also played around with the idea of some kind of mirrors to focus more sunlight on the panel, but then I figured that kind cuts down on the portability of the system. The panel itself is fairly lightweight, around 3 pounds I think, same as my laptop
I'm not a journalist, but I play one on slashdot
Amen. I don't care if a CPU is 5% faster than the previous generation, because with the 5% comes an equivalent or greater increase in power consumption and heat output. The laptop industry may be the savior of us all, and solar cells are a step in the right direction.
It's not convenient to sit in direct sunlight to even read a book. A shady spot, under a tree is much better, and, well.. there goes the solar power idea.
The cord is 10' feet long (about 3m) so you just have to find spot that is within that distance of a sunny spot, whcih except for heavily wooded areas, shouldn't be a problem.
I suppose if you wanted you could even mount the panel in or outside a window and use the notebook inside, but who wants to be inside.
Also, it can be used to charge your battery so you can take back into the shade once it is done charging.
Work for Change & GET PAID!
You call that cheap?
this is half the price for slightly more wattage (15 vs 13.8).
Work for Change & GET PAID!
Ive never been outside... What's it like?
Are you sure you need 15V to run your laptop? I've got an old Toshiba Libretto 50 which runs fine on 12V but only after you send it a brief jolt of 15V to convince the power management hardware that there actually is an external power source connected. To get the 12 V I use cheap sealed lead-acid camcorder batteries (Radio Shack 22-187 or equivalent), which I can get for as little as $25 each, and which run my Libretto for about three or four hours or so on one charge. I got the idea and plans from Xin Feng's web page, thanks Dr. Feng! Certainly a little doodad with a couple of 9V batteries will be easier to handle than a big inverter plus your laptop's AC adapter, and you can carry a camcorder battery or two around with you.
My Libretto runs Linux too; in fact it's a bit underpowered for them new-fangled power-suckin MS OSes, but Linux just sprints along on it, though it's a bit of a trick getting it installed because of the weird external floppy drive that doesn't work with Linux boot discs. Basically my trick was to yank the HD and get an adapter so I could hook up the Libretto's 2.5" hard drive to a normal 40-pin IDE connector like you see in a desktop machine.
Yours WDK - WKiernan@concentric.net
Suppose you worked outside all of the time for the expected life of the system, 20 years. Suppose that once you figure in the number of hours of daylight times the 'directness' of the sunlight cutting into the efficiency, you'd get about 7 hours of 13.8 watts. Then you'd get about 700kWH out of the pack over its lifetime. At $395, that works out to only $0.56/kWH. Not bad, only about 10 times the cost of plugging into a wall.
.15 m^2. The incident solar power constant is about 700 watts/m^2 at noon. At 13.8 watts, these things come out to about 12% efficient. Also not bad.
I figure these things are 2 panels of about 9" by 12" or about
So, obviously, these things aren't for everybody. But it is a good thing that prices have come down and they're manufacturing the cells more durably than before.
Maybe in a few years (with the power grid peak prices hitting $6000/MWH recently), someone will decide to build a solar panel power plant. It has the advantage of having its peak output at the same time as the air conditioners are using the most energy. It's just on the edge of being a practical energy source at $0.56/kWH. We'd just need to make lots and lots (and lots) of cells...
http://jcwhitney.com/product.jhtml?CATI D=5460
12.75V but should be ok $129
*Repent!Quit Your Job!Slack Off!The World Ends Tomorrow and You May Die!
But what do you do if the sun explodes? What are you going to do with your solar panels then?
They've been selling solar cells for laptops for a long time -- this is nothing new, but still interesting to look at for those didn't know these things existed.
MrSolar also has some laptop solar panels available -- kind of pricey, and he was a bit of a Y2k nut. Wanted to boost his sales, I guess.
Patrick
Hosting for Creators: http://rpg-works.net
I hate having to correct people, but StaticLimit was right. One watt is one joule per second. It measures instantaneous power. Watt-hours are simply watt multiplied through by unit of time relavent to this application, multiplied by an appropriate conversion factor (3600s/hr). Thus, one watt-hour is 3600 joules.
Now, look at his math. 79W-hr*3600s =2.84e5J. Okay, that's stored energy. Looks good so far.
2.84e5J / 3.5hr = 8.12e4 J/hr. Hmm, non-standard unit. Let's convert those hours into seconds.
8.12e4 J/hr / 3600s = 22.6 J/s. Why looky here! Joules per second! That, my friend, is out long-lost Watt.
"The best way to do mathematics is to be creatively lazy." -I. M. Isaacs
Just think - now in the summer we can get outside, use that wireless LAN to hookup to the server, enjoy the fresh air, and ... yes ... if you position those solar cells under you chin like so ... you can even get an even tan!
Cheers,
Toby Haynes
Anything I post is strictly my own thoughts and doesn't necessarily have anything to do with the opinions of IBM.
My subject line works on so many levels.
In fact I already thought about placing multiple solar batteries on the roof of my house to save on at least a portion of my Hydro bill.
Has anyone any experience with this? Are there other products for that use or do you have to build something of your own. I don't really want to have 20 P-Weasel bags on my roof!
You can't handle the truth.
I got one of those, bought a new laptop also, full stack P3. I got it on monday, plugged it in and NOTHING worked. I called tech support and they said
/that/ powerful.
:) Out side the door I seen people I knew from when I was younger. They starting talking to me, and poking me and making this awful sounds (Bob said it was probably laughter), confused and dazed I retreated back into my room to review the sisuation with Bob.
"Sir, the unit must be in direct sunlight for it to work"
"Excuse me?"
"Sir, you must take the unit outside with you, it needs to be exposed to direct sun light for it to harvest enough engry for it to power you laptop"
"uh, ok"
At this point I had no idea what he was talking about, but at the risk of sounding dumb I replied
"right-o boy, thanks it is working now"
Having no idea what 'sunlight' was, or where to download a copy, I did a search on http://www.google.com and came up with a few links.
My finds indicate that "direct sunlight" is "light" that is not produced by a light bulb, but rather an object that is referered to as the "sun". Easy enough I though, I take the unit and my laptop into the server room, and place the unit directly under a Sparc Station 20. Giving it 20 minutes (has to charge) the laptop still was not receiving power from the unit. Thinking quickly, a SS20 these days isn't
Pushing pass ethernet cords I set the unit directly under an a cluster of Ultra 10's. "That should do it" I proudly thought to my self, waiting, waiting, I was sure it was going to work this time. After 30 minutes I re-contacted tech support.
"Sir, *THE* SUN, you know, *OUTSIDE*."
Ah, I felt really stupid at this point. I decided to contact Sun tech support and see if it was a defect in the rays their servers where giving out. I relayed what the other tech support told me to Sun's kernel group, they to where making refereres to the "OUTSIDE". Hanging up before they thought I was stupid.
Loading up Netscape on my workstaton, I typed in http://www.theoutside.com and came across a punk band. After searching their site for 4 hours staight I still didn't see any "SUN"
*sigh*
Really depessed I started talking about my problem with this unit on IRC. A helpfully person by the name of "Bob76" on #bob_channel enlightened me to a whole other world. Not methophically mind you, but really a WHOLE OTHER WORLD. See said that someone in my room there would be an object called a "door" that was either made of wood or metal. Searching around and relaying my finds to "Bob76" I finally found the "door" after many failed attempts.
"Bob76" insturcted me to go out the door. Bob even helped me Crack the security methods on this certain door (I feel elite!
He said these strange cretures where *REAL* "people" and that this was known as "*real life*". Bob started getting weird with this topic, about people and life, really deep, but creepy.
quickly changing the topic, bob insturcted me, that their would be yet ANOTHER door after the first one, and maybe something called a "hall way" of other rooms with strange names like "kicthen" or "living room". Bob advised me to quickly open the door, keep my head down and quickly find the other door. He said this second door should take me outside.
Packing up the solar unit and the laptop, I thanked bob and decided to go for it.
I quickly opened the other door and these people started using strange launge like "hi" and "how are you", I keep my head down and didn't say anything like bob instructed, I quickly moved in and out of this maze of other rooms and "halls" and finally came upon the second door.
I started to sweet and time seem to stand stil, I reached out and opened the door. tossed the solar unit and laptop out on what appeared to be "green carpet, but real dirty" I push out and I knew I was outside.
My eyes started to burn from this intense light, and my skin started to burn, the light was really intense and bright, pushing on me, burning me, making me really disilluated and confused. I feel to the ground and all I could see was WHITE, burning my eyes, face hands, arms
I managed to find my way back into the second door and quickly close it. confused, but a lot better, I made my way back to my workstation, making sure I closed and re-enabled the security fearture on the first door I orginally found.
I felt really terriable for days after the experince, my laptop and the solar unit is still traped in this hell know to bob as the "outside". I think Bob is the devil.
I hacked out 20 thousands lines of ASM code, porting the Linux kernel to a embedded device I found in my alarm clock, after that I felt a lot better. It was only a 2-bit cpu with 32 byets of main memory, but quickly rewiring it, and using some ram I pulled from a CD-players LCD I was able to get a nice port of kernel 2.2.13 to it.
Anyways, I still don't know how I am going to get my laptop back, hell can keep it's "solar panel", I think it was sent here as a temptation from bob (the devil) to lure me out into hell ("the outside").
"`Ford, you're turning into a penguin. Stop it.'" -THHGTTG
Real Goods ( www.realgoods.com) has a variety of solar panels, including one which powers a laptop, so is comparable to the unit featured in the above story. Price is $369.00
Maybe they should work on a wind powered charger for as much hot air that blows though corporate these days.
Of course a solar panel isn't much use in an environment in which the Sun can sometimes be considered a myth used to inspire hope in the general populous. Though I guess if it opened out to the size of a football pitch it might manage to get enough power from the ambient light.
I used to live in Scotland and am now in Southern England so I guess I'm moving in the correct direction (but my feet may get wet if I continue).
Gamma Testing - Where testing is extended to the full user community (AKA Shipping the Program)
Carousel is a lie!
This would be great if I could actually see my screen outside in the daylight.
Claiming that your operating system is the best in the world because more people use it is like saying McDonalds makes
Real Goods and Jade Mountain, among others, have been selling these for several years now, for a wide range of laptops.
Solar cells recharging... my power is returning... BIIIIIIRRRD MAAAAAAN!