Solar Powered Laptop

[survient]

I'm working on building a briefcase laptop and I'm hoping to shove a panel inside the unit(kind of like voltaic's solar power backpacks and bags) and I'm having trouble finding a system that would work. I need to power something along the lines of this http://www.powerstream.com/DC_PC.htm but I don't know what kind of portable solar power system I need. I'm looking to have it be a hybrid panel/battery kit so the power supply for the computer gets a constant feed, and also be able to charge the batteries via an AC adapter as well. If anybody can help me with this it would greatly be appreciated. Thanks.

[scottsAI]

Hello survient,

Save your self lots of cost and work.

Use a desktop replacement notebooks if you need high performance. These are called gaming notebooks. Normal desktop draws 90 to 120w then add LCD monitor 28 to 40watts.

Above laptops draw less than 90w. Half the power.

Most notebooks will have low power modes to further reduce the power needed.

Have fun,

Scottl

[richhagen]

Many laptops will run directly from a 12V supply, even if the power into them normally is a bit higher to charge the battery.  BThumble rigged some old laptops with replacement plugs that run directly from a solar charged 12V battery for a school lab in Fiji.  It works really well.  With the hard drives replaced by compact flash cards, they draw less than an amp apiece.  They are running a DOS with a bunch of add on software.  I suspect that a newer laptop with a larger screen and a hard disk would draw a bit more, but from a small 12V sealed cell a small charge controller and a panel you should be able to power it for a bit.  Rich

See:  http://www.fieldlines.com/story/2007/6/5/85322/76409

and WWW.smallsolar.org for more information on that project.  

[DamonHD]

Hi,

If the machine doesn't need to be very high-spec then you should be easily able to draw less than 20W, down to as little as 10W while idling with some machines.

Have a look at my partly-solar-powered laptop (~18W):

http://www.earth.org.uk/low-power-laptop.html

and also Intel's work on this, especially with Linux:

http://www.lesswatts.org/

Rgds

Damon

[AbyssUnderground]

My MacBook draws as low as 12 watts when idling and this could probably be pushed further if Damon's custom Linux distro was used on it to further disable things that aren't needed and to enter further sleep states. The MacBook also runs on a 10.4v battery making it ideal for running on 12v (but its power supply is 16.5v which I don't understand... Maybe it runs with the cpu speed lower on battery, something I'll have to investigate).

[wooferhound]

Not all laptops can be powerd directly from the 12 vdc battery power but a large number of them can be...

http://www.fieldlines.com/story/2005/2/24/225230/527

http://www.fieldlines.com/story/2006/7/13/21756/8923

http://www.fieldlines.com/story/2004/10/10/173020/87

http://www.fieldlines.com/story/2004/6/22/15321/6392

[DamonHD]

Note that I use a laptop power supply for a car (ie 12V cig lighter plug) which seems to be well over 90% efficient.  (For my laptop I need 20V in.)

That means it keeps my laptop's batteries charged too and uses <1W of extra power.

It almost certainly also protects my laptop against nasties on the 12V such as spikes from the turbine, etc...

Rgds

Damon

[ghurd]

I bet you believe nobody told you what you need to know.

If you are looking for solar and a battery to run a laptop, the choices are a huge panel or lower power drain.

A briefcase packable panel is a novelty at best.  And it will not do anything if it is packed.  Unless it is left out pointed at the sun during daylight, it won't do much at all.

Changing laptops would be overall cheaper for the entire project.

My new Toshiba/Vista laptop uses 10% of the battery booting up, by it's count.

My bro-in-laws Mac Book (?) very rarely gets shut off (not even overnight).  He can use it for hours on the porch.

G-

[zeusmorg]

 Solar panels that would be sufficient to keep up with your laptop would probably run into the 500+ range, that are portable. Cheaper portable solar panels wouldn't give you much runtime, they mainly just extend your battery time. You may be better off setting up a battery backup system, like two SLA batteries, and a power converter suitable for your laptop. If you truly want it solar powered, you could always set up some panels at home to recharge them while rotating them out daily. Unless you're going to be away from any power source for days, solar powering a laptop is quite expensive, and marginal at best. The power supply you showed is mainly for in car computer systems, and wouldn't be needed for a laptop. all you need is to supply the proper voltage which is listed in your owner's manual or on the power plug. google flexible solar panels, rollup solar panels.

[wdyasq]

ASUS Eee Laptop with Linux

Battery -4 Cells-5200mAh 3.5hrs runtime (tested)

Somewhere I saw 12-15 Watts power - 20 second boot time - 120VAC to 9.5VDC converter

http://tinyurl.com/2fwmht - Newegg link

Be a good unit for limited power applications.

Ron

[survient]

I appreciate the advice. My main reasoning is I'm looking to trickle charge the batteries via solar power, not power the unit solely on solar power. The unit itself will have 3 or more batteries powering it(yes a longer required charged time to make them fully charged). A heavy emphasis is placed on the weight and power consumed by laptops these days. I just want to focus on the processing power and the reduction of energy consumption(a hard thing to balance) and less emphasis on the weight. There are plenty of low power slim profile desktop systems out there(MiniITX and similar) that could be integrated into a mobile solution with some tweaking. Most of the time the unit will be powered by AC(also be charging the batteries as well). My main obstacle is finding a solar panel system and integrating the required batteries to have it set up to trickle charge, and at the same time still accept AC as both a power source and charging source. At first I wasn't even going to bother with solar power but I saw the panels that trickle charged car batteries while idle, and that caught my attention. When finished, I'll make the solar panels detachable from the briefcase itself and adjustable to optimize charging efficiency, however in most cases where I'm presented with the opportunity to adjust the panels, I'm also offered an AC outlet(or I'm in a car). A major source of my confusion is the batteries I need to use, how to hook an AC supply to charge them, and also which solar panel I can use that will successfully trickle charge them. Thanks.

[survient]

Also I found this unit, http://www.mini-box.com/s.nl/it.A/id.301/.f?sc=8&category=13, I looked up the specifications on the AC-DC adapters they had for it, and it looks like the range would be from 5A to 8.5A of power, at around 12V for a supply. What I need to know for this is the batteries I can use to power it, and a solar panel that can trickle charge these batteries. Thanks.

[ghurd]

Did you see "I bet you believe nobody told you what you need to know."

My car is blue.

I get a some free gas sometimes. Sometimes my wife uses it too. She has black hair.  I drive it to work sometimes. It has a sunroof and a Sony stereo. I used to work in a factory, but I quit.  Now I have a better job and the driving distance is a lot different. My old boss was named Frank, but the new one is Chuck.

My car is blue.

How much will I spend on gas next week?

A $10 PV will successfully charge a 12V battery.

That do-hickey is a waste of money if I remotely comprehend what you are trying to do.

[survient]

The panels will be detachable and able to be mounted/adjusted while the unit is stationary to optimize the amount of charge the batteries get off the panels. I'm looking at panels similar to these http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&viewitem=&item=270201167593. I'm getting a better idea of the concept, however I'm still lost as to what kind of batteries do I need, which panel will work with that battery(charge the battery successfully), how do I hook the panel up to the batteries, and also how I get an AC/DC adapter integrated to charge the batteries/power the system. I'm not trying to power the system via solar power, just trying to integrate it as an added feature. I'm straying from buying a stock laptop as they place a much heavier emphasis on the weight than I'd like. My goal for this is to create an efficient balance between processing power and the reduction of energy consumption, putting weight as one of the lesser problems. Most laptops just have the 1 battery, weigh around 10 lbs(if that) and are extremely small, as these are things that most consumers look for and expect. I'm looking for a heavier unit, with 3 or more batteries(or a battery equivalent to that of 3+ laptop batteries), about the size of a medium to larger sized breifcase(given that the unit itself will be integrated into the briefcase). Not to mention I'll actually be able to work on this unit, as I built it myself, I know the guts of it, and if I need to make changes I can. With a normal laptop I'm forced to run out and buy a new one, get used to it, and then repeat the cycle in 5-6 years. I know what I want for this project, I just don't know how to get around the power issue, specifically which order each component(Batteries, solar panel, and AC/DC adapter) goes in, and how to connect it all together.

[spinningmagnets]

I'm new and still learning, but...

It's my understanding that input voltage should be about 10% over nominal. A 12-volt car battery is charged by a 14 volt alternator, Dan's 48 volt RE pack is occasionally charged by a steam-powered PMA that puts out 54 volts, etc.

Since a laptop can be charged by a 12-volt car socket charger, any 12-volt supply could be connected to a car-charger adapter.

When it comes to RE home batteries, bigger is better. For a small briefcase 12-volt battery you can get good info over at "endless-sphere.com" they experiment with electric bicycles.

The cheapest, heaviest, largest, and shortest range batteries are Sealed Lead Acid (SLA). Each type upgrade has a smaller size/weight, and better range (each type also has a bigger price!). Next is NiCD's, then NiMH, then the best that's easily available is lithium, but there are several lithium types, the great new ones you want are LiFePO4. Several cylinders can be found inside DeWalt cordless tool battery packs.

http://endless-sphere.com/forums/viewtopic.php?t=2498

Several can be attached in series to reach the desired 12-volts, then attach the 12-volt series strings in parallel to gain additional amp-hour battery time.

Take everything I say with a large grain of salt, but I would guess a 14-volt solar panel could charge a 12-volt LiFePO4 battery pack. If you're good with a soldering iron, you can get a free schematic for a custom smart charger (turns off when full), or the guys at e-bike.ca will make one for a price. A custom 12-volt battery like this should be able to power your laptop through the standard car charger.

[independent]

Hello there.

Here is a link I found interesting and possibly relavent to your laptop powering needs.

this instructables link loosly tells you how to power your laptop using another kind of battery. I would use this with one of Ghurd's controllers a sla and a small solar panel.

The panel provides power. The thing is you need to find out is the correct battery voltage of your laptop. This is not clearly stated by the person instructing(?). Some older laptops use 3x 3.7v Lithium ion cells or 6x in parallel. These are the ones I would use as a 12v sla is perfect for that. The internal battery has a circuit which should monitor the voltage and give an accurate reading. This is what I plan to do.

While we are on the topic of laptop batteries/power; if you want to increase or rebuild your laptop batteries here is another article which is fairly rudimentary but gives a good overview of that.