How hard is it to generate about 10 - 20 watts renewably?

Question

Thanks to a power meter thing for my centrino laptop I know it doesn't go over 35 watts consumption even at full chat... when in economy mode and wordprocessing it's somewhere between 8 and 9.5w... and of course even less when the screen & disc turn off, then it standbys, then hibernates.

So if i could generate this kind of power from solar, prevailing wind, a windup thing, or even just a crank I could gently turn, I could compute for free (internet for free, if i find somewhere to leech wireless from!).

Thing is i have absolutely no idea what this represents. How tired would my legs get on the exercise bike arrangement / feet on the converted 1800s sewing machine treadle? My hands on the wind up crank? How big a solar panel for typical uk use?

If I make clever use of energy saving bulbs and a pumped water storage system i'd only have to add about 50% capacity to be lit the same way :-)

...saving just a teensy little bit of power to justify my 1kw fan heater on icy days. Brr!

Answer 1

There is a new type of External WIFI Antena at the CCRANE company that runs off a USB PORT EXCELLENT for WIFI super gain...for long distance access...Check it out..
Start up load is usually DOUBLE the wattage for some electrical devices....2 6volt batteries and a 15 watt solar panel should give you an easy 8hours of computing...MOST Modified sine wave inverters DO NOT like the load a charging computer puts on them...especially at start up..its not uncommon to get an ALARM
as the voltage requirements go up..
If it was me a deepcycle 12 volt battery...89.00 a 400watt inverter
36.00 and a 15watt solar panel..150.00 and your on the way to Solar computing..JUST A NOTE on ANY Battery powered system...if you dont use a deep cycle battery...dont go below 50%
DOD depth of discharge it will make the battery last longer.

Answer 2

It is very easy to generate electricity with the right piece of kit. However you will face two big problems: reliability and quality of supply.

Renewable power like wind and solar is great but not constant. You should think about using this power source to charge a battery so that you have the power on tap when you need it. Otherwise, if you had an overcast day or a day with little wind you would not be able to power your laptop.

The second issue is quality of power i.e. frequency. The frequency of the grid in the UK is 50Hz and there is a small margin of tolerance so over a short period of time it would not be uncommon for the frequency of the supply to vary between 48-51 Hz (think you should look up the exact figure). Computers and other electrical goods will not function correctly unless the voltage and frequency are constant. You will need to think about how to regulate the voltage and frequency produced by your source to 230Volts and 50Hertz so that your laptop will work.

Great idea! Best of luck with it!

Answer 3

Generating 35 watts renewably is a piece of piss, and several fairly cheap devices are available commercially. You won't even need to generate this much if you've got rechargeable batteries, since you only use your computer a few hours a day. You can buy a windup generator, solar panels or a wind generator. For more information go to a supplier like Radio Shack or Dick Smith Electronics, depending on where you live. A fit adult working flat out can generate about one kilowatt, which is just enough for a man powered aircraft. So you don't need to work very hard at all to crank out 35 watts. When you're lying in bed doing nothing you generate about 100 watts of heat.

Answer 4

In the UK these days even in Northern Scotland you can see quite a few weather stations with solar generators on top. Without knowing too much about these I would say they are of similar output to what you want - the solar panels are about 1-2 square feet.

Another thing to consider is the voltage - you can easily generate at low voltage and most computers can be made to run on 12 volts. You can increase efficiency by removing as much voltage conversion as you can. 12 volts also has the advantage that you can store surplus electricity in a car type battery which are relatively cheap these days.

Answer 5

According to Wiki an average "in-shape" cyclist can produce about 3 watts/kg for more than an hour (e.g., around 200 watts for a 70 kg rider), so this iw well within your 10-20watt range. The cycle-generator combination will be about 50-60% efficient I suspect but as you wouldn't want to be pedalling all the time, lets add another 50% loss in charging the batteries. So, to generate 20Watts, you'd need to work at 40-80W or at 200W per hour, about 20min pedalling would give you an hours charge (all very rough figures).

Don't forget, in the Second World War they used hand cranked generators to run transmitters and receivers on the field so it's not an new idea.

Alternatively, Maplins sell an 18W solar panel for £180 which will power your laptop while the sun shines. That should keep you off the internet for most of the time if you live in my bit of the UK! Plus, if we assume a unit of electricity (1kWh) costs an average of 10p, you'll have to use up 1800kWh of electrcity before the solar panel pays fror itself. At max consumption of 20W that is 90,000 hours of usage or just over 10 years powered on usage. If you use your laptop for 8 hours a day, it'll be 30years before you get the solar cell saving paid for and I suspect in 30 years time the power requirements of your nanotechnology implant will be zilch. Plus, if it takes you 30years to get payback, you're talking a return of your money investment at roughly 3.3%, so putting your £180 into a bank account giving you net more than 3.3% APR you'll be able to pay your lecky bill and make money.

You'd be better putting on an extra jumper and turning off the 1kW fan heater for about 10 minutes, which will save enough energy to run your laptop for 8 hours.

Answer 6

Get a wind turbine no legs requires