would like to run computer straight from 'cells'

[dudevato]

Can you give me a ruff estimate of how much $ would be needed to run a conventional PC/monitor and 110 volt am/fm stereo (the kind you'd use to amplify a cd player or tape deck) I will only be using this amp to amplify the computer. I'm in southern california and have very little clouds in the sky. The pannels would be in a fixed position and an ideal location.  I'd like to see if this is a do-able hobby investment. I'm thinking I'd only need some solar panels and an inverter.  I know I'd only be able to run this while the sun is shinning. Can someone give me an educated guess as to what my investment would be?

Then one more 'amount'please: If I wanted to incorperate a 12 volt battery into the system. I guess I'd need a 'charge controller' also. I'm thinking I'd what to use the computer/amp for 3 hour a day. Is there anything else necessary?  Thankyou for your time and knowledge.  dudevato in Lancaster (60 miles north of Los Angeles

[AbyssUnderground]

To begin with you WILL need a battery. The panels on their own will not work since their power can vary even with the slightest dim light and the inverter will not accept the wide range of voltages.

[12volt dan]

And a regulator.

I run mine with solar(it's a 3 year old Dell) but first you should figure out the amount of power it draws. Use a lcd monitor to cut down power, they draw a lot less. My tower draws about 250 watts (max) so if you had about 125 watts of solar with a regulator(one you can grow your array with) and a couple of batteries your probably looking at around $1K, maybe a little more. You will be hooking it all up yourself and the wireing or cables will cost on top of that

 Thats about as ruff  as it gets :^)

[scottsAI]

Hello dudevato,

First dump the computer if it's a desk top, get a laptop, will save you money.

Many laptops can run off 12v directly or at least with a cheap booster (28$).

Desktop will draw 120 to 200w, all depends on what system you have.

Then the monitor can draw another 70 to 150w, look on the label. Like the other guy said use LCD.

Solar power cost $6/watt, so to make it with a desk top 150s + 100w = 250w * $6/w = $1500

My laptop 1.6ghz draws 30watts, for the computer and display. Solar cost is $180.

Take the difference (1500 - 180 = $1320) and buy a nice laptop!!!

Then get rid of the stereo. Car stereos used to be a good choice until they started producing the 500w ones. Maybe a nice boom box, with efficient speakers a lot of power is NOT needed to make a lot of noise.

With solar, you can replace your "loads" with newer lower power units and save money in the long run. Each watt saved, saves >$6 in cost to produce it.

I have over simplified some of the issues. Do not buy anything until you understand what all your options are. Later you will be wishing you had.

Have fun,

Scott.

[drdongle]

You can get internal 12 volt power supplys for desk top machines. most computer people dont know about then but they are available. I have one that is a 48 volt input. I believe Globaltek is making them as well as others.

[Clifford]

On the idea of 12V

You can look at some of the small desktop boards.  They have very simple 12V power adapters available.

For example the EPIA Mini-ITX

Also look at LCD monitors.

[scottsAI]

Thanks drodongle,

I was going to mention the power supply can be replaced by a DC converter, more costly than a regular inverter, the assumption is it's more efficient than using an inverter plus regular ATX power supply.

It got late, forgot:-)

Looking at the label on an ATX supply efficiency: 65-70% at full load, sort of wonder what the efficiency is at the normal lighter loads. 70% is sad, it's only a few percent better than a transformer and a linear regulator. ATX supplies are MUCH cheaper, the driving force!!

After digging around I found the best ATX power supply is only 80%, terrible. Not worth the cost.

You may wonder why I know this? I have 22 SETI computers, electric bill just for them is $125/mo in the winter, $170/mo in the summer. I spent 6 months looking for ways to reduce it. After much work, I turned them off for the summer! (AC bill is 71% lower). Next step is to wire up two or more computers on one supply, use water cooling, dump the heat outside in the summer and inside for winter. Figure out how to get rid of some fans etc.

Have fun,

Scott.

[nothing to lose]

It was mentioned you'd need batteries already. But also remember batteries will save you on solar costs too!

 You said expected use is about 3 hours a day right, so if you have 6 hours of good sun and batteries you need only half as many solar watts. If you tried to run directly from solar then you need the total watts all at once from the solar.

So if you need 200watts per hour to run the system, trying to go direct from solar pannels you would need at least (more) 200watts of pannels per hour fulltime @ $6 a watt = $1200

If you have 10 hours of good sun and some batteries you need 600 watts for 3hours use total, 600/10=60watts x $6 so around $360 in solar. With loses etc.. not perfect sun and soforth you need a bit more than 60watts solar but you see what I mean anyway. Lot's of money saved on solar pannels to buy a battery or two.

If you know you will have basically the same load all the time and size everything correctly for that load you may not need much for a charge controller if your going to be around to watch the system a bit.

I control my wind stuff manaully still. Because of tall trees and I travel most summers I put it up and take it down, so I never bought an expensive controller yet for my system.

[asheets]

I have a rackmounted UPS that I've modified to charge via my solar panels.  A smaller one (such as a SOHO UPS) will keep a desktop computer alive, but will die within seconds if I hook a crt up to it -- thus the use of my big rackmount one.

It takes quite a few of those Harbor Freight 1W panels to keep this thing running.