The rest of this forum is interesting, but I'm looking for practical info, how-to's, articles relating to running a computer off solar panels. These things are available right now, and almost anyone in a sunny location who has a good view of the southern sky could run his computer off solar power.

To that end I bought a small 5w solar panel from Harbor Freight. When I'm done with the project I'll be able to run a P4 setup completely off solar. Of course I need a big battery in the system, charged by the solar panel. And to simplify the project, the computer uses a PICO 12v dc/dc converter. With this setup I'm limited to an hour or so per day running the computer, keeping the battery fully charged. If I need more time powered up, that's possible with the battery......but I then need to charge for a few days without turning on the computer. The testing is going ok. I'm in the process of mounting the panel in such a way that the angle can be easily adjusted for the changing seasons. This is all new stuff for me, but doesn't seem too complicated for a beginner in solar power usage.

Thats all pretty cool, but if you own your home, and you plan to stay for a long while, then putting grid-tied solar for your whole house in will give you a lot more power, and you won't have to worry about run-time and such, as the grid would take and give what you need or have extra, with environmental and economic benefits.

On that setup, you could probably add another panel or two to lengthen up the run-time, you might also need another battery. A charge controller would be a worthwhile addition so that you get the most out of the battery. Most off-grid house systems use a charge controller to store the energy in a bank of batteries. Effectively, you are just building a much smaller off-grid system, even though the rest of your house (I assume?) is still on the grid.

And WOW, I could NEVER live with one hour of computer time a day. I guess if I did something like that, I would have a few more panels.

With this sort of project, it's best to start off small without too big an investment. If it doesn't work out, I can still use the panel just as a battery trickle charger. I have run the computer over five hours on the battery alone, so I'm not really limited to one hour usage. If the battery ever gets too discharged on the solar panel, I can switch over to a large AC power supply that also will charge the battery. This project will require some usage before I find out how it goes. I'd hate to build a big solar panel setup that wasn't being put to full use. Harbor Freight also sells a much bigger solar panel setup (30w), but it's $200.

If you were to grid-tie it would have to be done by a professional installer, they would make sure that it would work. They are pricey, between $10K and $60K, but there are federal and state tax rebates, and sometimes power company incentives to build their renewable energy portfolio in many areas.

They have about an 8 year ROI in most areas, so they are a good investment, both monetarily and ecologically. First, however, you should invest in energy efficiency, like energy star applicances, CFL/LED lighting, ETC. France has done a better job though, they just use nuclear plants.

nuclear is not renewable energy (in fact it's the ultimate non-renewable energy) and there is a surprisingly big anti-nuclear movement in France. no nuke plant has ever been delivered on time and on budget in W. Europe,the capital costs are enormous, and the waste problem looms over the whole thing like the elephant in the room no-one wants to talk about.

The problem of the finite quantity of fuel available could be effectively solved with the use of breeder reactors, which would push the time until we run out forward by millenia. The waste problem could be almost eliminated by the use of... breeder reactors. We even had one here in the UK once, but it was shut down due to short-sightedness.

There is really no way (yet) for renewable energy sources to supply all our power, and the most sensible source to make up the difference is nuclear.

Well said. It might take 30 or 40 years to figure out how to use the waste as fuel, but hey, thats what Yucca mountain is for.

I look at it this way: coal or nuclear? Even with IGCC/CCS coal, I'll still take nuclear. The mining is environmentally detrimental, but it can't be nearly as bad as blowing the top of a mountain off to get coal.

In France, so what if they stay on budget? The electric company is owned by the government. They have the cheapest electricity in Europe anyways.

On the other hand, nuclear needs to be cost-effective in the US and other countries, where de-regulated, or at least private energy markets exist. In this case, nuclear is very compatitive with coal, and the load factor of the plants has nearly doubled over the past 20 years, to around 90% now.

If a governmental carbon tax, or emission caps are put on the industry, then it becomes even more cost effective. There are plans for 28 reactors in the US now, we need plans for about 280, energy efficiency, renewables, and THEN we could have a zero emission grid.

I think that the government should regulate greenhouse gas emissions differently in different sectors. In electricity generation, the utilities have a silver bullet solution (nuclear), wheras steelmaking needs high carbon coke to make steel, and cars are somewhat inbetween, as they will hopefully move to plug-in hybrid electrics that use biofuels.

I think Blue should make a Mr. Coffee Fusion reactor for his computer. Other than that, the solar panel looks like a neat hobby to try out. There, back on topic.

a lot of people tout breeder reactors as a panacea, but the fact that breeder programmes have been shut down all over the world suggests to me it was not as promising a technology as everyone is making out. who wouldn't want an infinite fuel supply??



and there I was thinking there was more than 2 ways to get energy. silly me. In the US you have some of the most abundant solar resources in the world, use them!



the current once-through fuel cycle for PWRs is wasteful and stupid, period. A silver bullet it ain't.

A new follower of Al Gore !!!

The one big problem which they do not solve is politics. Of course they are not the perfect solution, but there are no perfect solutions, only better compromises.



Using 100% renewable sources would be ideal, but, in the case of solar, it's still extremely expensive and the fact that not all areas receive enough and it's absent totally for half the day means you need efficient storage and transportation, which is also extremely expensive and not currently practical.

All renewable sources have similar problems, which while soluble, make them a long-term solution, not a fix for our immediate problems.

Stop that....Al Gore is a curse word, in my book.

The panel is up and working. The wiring into the house is already there. I'll use the RG56 line that went to the dish.....plenty big to handle 5W. The final adjustment angles need to be figured. There seems to be several theories about the proper angles for a fixed dish. I have my own. I'll be playing with this for a while, not during a possible storm however. As the pictures show, I just cut up a dish that is mounted to my car port. The mount was left intact...and has the correct adjustment ability. These little dishes can be had for free.....I see them in trash piles frequently. They can be mounted to a roof, to the side of a house, or to a car port support beam....like this. I used some cedar fence wood. The stuff lasts forever. Just turns black with age. More to come.

I've been thinking about a similar setup myself for "emergensies". How well does the pico psu and the motherboard handle the varying voltage you can get from a car battery? If my understanding of the pico is correct the 12V line is pretty much passed through unregulated, and a fully charged battery might give in excess of 12V.

On the other hand, I don't know what tolerances there are in the ATX spec... How many percent is the voltage alowed to vary and still be acceptable?

@jaganath:

We can figure out how to refine the waste at some point in the future. For now, we need a lot of carbon-free energy.

None of the other forms of energy can provide a large proportion of the world's energy quickly enough to slow climate change.

Natural gas doesn't have a good fuel supply, and still puts out a lot of CO2.

Wind doesn't put out constant energy, but could do 25% in some areas.

Solar is somewhat more predictable, and holds the most promise of the renewables.

Geothermal is only available in a few areas.

IGCC/CCS coal is just ridiculous, and a completely untested technology.

If Nuclear is not a silver bullet solution, at least it is silver buckshot. And a lot of buckshot.

@Mr Evil: Well said.

Cool. There is a PicoPSU that is for cars, can handle from like 9-26VDC.

ATX says ±5%, so 11.4-12.6V is within spec.

Trekmeister.....I can answer that question somewhat. The 120w PICO I'm using, will start and run ok with a maximum of about 13.8V. Go higher and it refuses to start. This P4 setup will continue to run as the battery discharges, to at least 11.4V. I haven't tried anything lower. I left the thing running for over five hours on the battery alone. This is a very small car battery.....330CCA. Car batteries can be had over 1000CCA. But they get pretty heavy at that point, hard to carry around. I might mount the battery box in the living room closet.....and run some wires out to the computer. I can monitor the state of charge using the volt meter in the first photo. PICO does make a dc/dc converter for automotive use.....it handles a wider input voltage range.

Interesting stuff about the voltages... Almost 14V sounds like it could be quite bad for the components...

I like the concept of powering the computer from a car battery directly, since the efficiency is a lot higher than using an inverter. Should be quite easy to build a nice little on-line UPS using a pico and a car battery or two.

How high capacity is that battery of yours and have you measured the power draw by the computer? Oh and are you powering the monitor from the battery too? I guess some of those new fancy flat screen monitors should accept a 12V input.

Auto batteries don't measure much over 12V, except when the engine is running. This is a small 330CCA battery. You can buy a lawn equipment battery that is that powerful, and smaller than this one. Auto batteries are much cheaper however. This computer I'm using (Rubbermaid computer in the cases forum) draws about 45W at an idle. Something like an EPIA computer would run on 1/2 that wattage. I have a 12V monitor that I'm going to use.....not hooked up yet.

I think this would be a perfect solution for a friend of mine who wants to bring a computer out on his small island. He already has a number of solar panels to power more essential stuff and he was thinking of adding a couple more for "play-stuff". I think he has an old P3 and a P4 (northwood) that are expendable. One of those and a small LCD monitor should be great.

And regarding battery capacity I was more after amp-hours (Ah). CCA is mainly about hight current discharge and that is not what we are after, right?


(hmmm... just realized we are talking about lead-acid batteries in green computing... those aren't exactly enviroment friendly. )

CCA is just another way to measure battery capacity. This battery reads 88 minutes of cranking @0F....356A. But it's not new......when I test with a real battery tester it measures 330CCA. It was below par so somebody warrantied it.....I ended up with it for free. I have had it a few years, sitting around here as an emergency source of 12V power.

FWIW.....these lead-acid batteries are not just dumped these days. Most are recycled for the lead. You pay a big premium at most places if you don't have an old battery to exchange for a new one.

But what about upgrading to the more eco-friendly NiMH batteries? A dozen or two D cells in an array might work....

Let's see, 2 D-cell 12000 mAh batteries cost $20-25. To get this up to 12v wired in series you'll need 10 of them for a cost of $200-250.

A deep cycle lead-acid battery might cost $100 and have 50 Ah of capacity.

So the lead-acid battery is going to have 4-5x the capacity and half the cost giving you a price/performance ratio close to 10x.

If you already have some old lead acid batteries the cost may be negligible!

I suppose if you were a real cheap person (not me of course), you could buy a second battery for your car, and just swap it into the car as your computer discharges it. Just leave enough current in the discharged battery to start the car. Forget the solar panel completely. With moderate computer use, you could get 2-3 days off the battery before you'd have to do the switch. Sure....charging a discharged battery does use a little extra gasoline in the car. But not that much. Probably couldn't measure it.

I thought about BF's new toy today when I came across this:

HP intros ultra-green slim PC.

While the EPEAT Gold certification, "95% recyclable materials", and 240w 80+ certified PSU are all fine and dandy, what caught my eye was in the Configurer:

AEG-XP1500-110 Solar Power W/5 AMP AC Charger [Add $1,325.00]

I can't say I've ever seen that as an option on any big-name PC builder before. Unfortunately,HP's nearly useless website doesn't provide any details on the option. I'm curious to see if it is capable of running the machine full-time or not. Even searching for the part number doesn't turn up anything. Considering that the option more than doubles the price machine I doubt many people will be selecting it, but it is interesting nonetheless.


Yet another idea you should have patented Carl.

Hmmm, if this only took them one morning, why didn't they do it before?


On-topic: Great work, Bluefront!

I couldn't find it on HP's site either. Then I tried google and found the above mention on this forum. While I was on hold with HP I tried google products and found this on HP's site:
http://h30094.www3.hp.com/product.asp?s ... agemode=ca

So I had to join this forum and post it!

I also found HP's OEM on this:
http://www.solar4power.com/solar-power-devices-2.html
They sell it for $1229, so I don't know if HP includes shipping or if it's just an upcharge.

I have been interested in this topic for a long time, particularly with work I do in Africa at remote places with plenty of sunshine and an electricity supply that can go off for days..

The solution we built consisted of 3 deep cycle batteries that were charged by the mains (in parallel), via a charge controller and were topped up by a 5 watt solar panel. When the mains went off, the batteries are automatically switched to take the load. Ideally a larger solar panel which would provide the majority of the charge and using mains as a backup would be better. This would get by your problem of only being able to use the pc for an hour a day. Larger panels are expensive and you need a bigger charge controller (more money) and we didn't have a larger panel anyway..!

The batteries provide power through a square wave (cheapest option) 330 watt inverter to power a fridge, a laptop and an all in one printer / copier. This lasts for about 2 days normal use..assuming you don't open the fridge. The batteries are deep cycle, truck batteries...cheapest option and available locally.

The laptop is great as it provides monitor, keyboard etc etc in one box and the printer / copier is just fantastic...again all you need in one box.

If you could find a low power laptop that runs on 12 volt (say from 11.4 to 13.6) and also a printer / copier that could do the same that would be great..this would mean you don't need the inverter, which I guess is only about 35 percent efficient.

In Africa all the solutions I have seen have ended up using solar to charge batteries which then power an inverter to get back to 110 or 220 volt.

Hope this makes sense...Bluefront it will be interesting to see this topic develop..based on the time and energy you have put into your previous projects I am sure you will reach a workable solution.

Wow....those commercial units are expensive. Here's what I have in my setup.....less the computer of course.

Solar panel.......$40
Battery..............free. A new deep-cycle battery of 700CCA....about $56
Battery case ....$15
My fancy plug-in volt meter.....$15
The 3-outlet plug sitting on the battery box.....$12
The mount......free. You could build one out of scrap wood.
Wires.......free. Practically any old wires will handle 5W.
Wire harness from the battery to the PICO....home-made using an old Zip drive cable.

Cheap stuff. All of it can be used for other purposes. I do have a few dc/ac inverters, but I also have a lot of 12v stuff. No need for the inverter.....wastes too much power. A commercial unit like the link looks nice......but can be duplicated much cheaper

I still am figuring how I will wire this setup. I think the battery will sit in a closet, wired to the solar panel with RG56 {TV antenna wire}. I'll wire the 3-outlet plug to the battery with a short cable....sit the plug on the desk. This plug can be turned on/off with a switch. You wouldn't want the PICO connected to the battery except when in use. It has some current draw even when off. I am deciding how to hook up a real battery charger.....which I can turn on if the battery gets too discharged. I'm not sure if my Radio Shack 13.7V power supply will work in this setup. Still working on a few ideas.....Obviously I'm doing this thing on the cheap. If I like the setup, I can always get a bigger solar panel. The inside stuff would work the same. We'll see.....

Here's a diagram of my latest design for the setup.....



In this diagram you see a "Smart Power Strip". This can be attached to the computer with a USB cable. When the computer turns on, the upper four plugs turn on. This would enable a small ac/dc power supply to turn on only when the computer is on.....could keep the battery from discharging when the system is in use. The rest of the time, the solar charger would charge the battery.

Another way to do this would be to put the small charger on a standard timer, and you could figure how much charge time was needed to keep the battery charged. Run this charger at night....let the solar charger run during the day.

In the diagram you see a diode in the 12V line from the solar panel to the battery. This is standard procedure to prevent the battery from feeding back through the solar panel. If you attach a std charger to the battery (like the diagram).....it will not feed into the Solar panel. This diode is internal to the solar panel (came with the panel).

If anybody sees anything wrong with this diagram, please tell me.