I'd like to hook up a computer that would be dedicated to data logging for my PV array. I'm thinking of building a bare bones PC that would consume as little power as possible. So no sound card, minimal RAM, basic video card, unplug the monitor when not in use, utilize bios power saving features, etc. Does anyone have other suggestions along these lines?
It only needs to run during daylight hours of course. Obviously a lamp timer is not going to cut it. Does anyone know of a way to start and/or stop a PC at certain times of the day? I'm up before dawn most days anyway but it would be nice if there were a way to automate it.
Thanks!

Two ways to do this ...

#1)

The solar-guppy servers are based on a neat , low power plateform called mini-itx. You can find out about these wonderfull little boxes at Mini-itx

The solar-guppy servers are the fanless , 533 mhz ones ... you can get a case and motherboard for about 160.00 , just add memory and disk and your done. I used a laptop drive and the MEASURED peak wattage , running disk performance tests was 11 watts , idle , they use 7-8 watts , not even worth turning off.

I have a pair , on 24/7 , powered by my grid-tie system

#2)

Go to ebay and find yourself a CHEAP old 100-150 mhz deal. I have a couple of the Compaq LTE 5280's (120 mhz) and used then to run fishbowl data logging 24/7. Nice thing about this is it includes the screen

You can find these things for about 50.00

[ 12-11-2003: Message edited by: Solar Guppy ]

Thanks for the reply. I hadn't seen those ITX PCs before. They're cool I'll have to do a little research.

Old laptops worry me. I bought an old one once (486 DX2 vintage)and the battery went bad. I thought "no problem" because I was fine with running it from it's AC adapter. But the battery was so integral to the laptop that it wouldn't run from AC unless there was a healthy battery attached. The replacement battery was going to cost more than what I paid for the used PC.

Thanks again for the suggestions.

The ITX are really nice little computers , that is what I recommend as a first choice

The Compaq LTE line I know for a fact work just fine on the adaptor only , they can be had for 50 bucks and up

I just did a quick look at ebay and the lowest price for a complete one (Hard drive and OS) is 69.00

Cheap when you consider that a TFT LCD screen
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3447160692&category=3712

Thanks again for the reply!

Out of curiosity,how much power does your power does your compaq laptop consume?

They draw less than an 1 amp at 16 volts dc ..

So something less than 16 watts ...

I myself just got setup with a itx board and like it alot (to run a website 24/7). i am using more power than id like, however i got the m10000 1ghz nehemiah and according to a website im probably in the 30 watt range running direct of of 12v dc.
i have a usb webcam, a notebook hardrive and thats it. i plugin a standard size cdrom if i need it temporarily. i am borbderline being able to keep this up on my small battery pv system so i have to keep power low. I have yet to measure it but plan to. theres a nice little power calculator on www.mini-box.com here: http://www.mini-box.com/powersimulator.html
dont know how accurate it is i havent compared yet as i say

Ive read something about power limiters for the board (via itx boards) that can slow down the cpu speed (and consequently power) and was interested in at least trying it. anybody have experience w/that?

i have an older laptop thats b&w vga (think its a p-1) with win3.1 on it & a 500mb and a mostly dead battery , but it runs at about 11 watts.. may try something with that.. no cdrom though..

Is it possible to drive a PC off of DC instead of AC? Any good DIYs for doing this?

Stock PC's use ATX sytle power supplys ... the output voltages are mixed , 5V,3.3V+/12V ect ...

The cost of changing out a ATX to a 12 volt only input is pricey ... its much cheaper to build a NEW mini-itx type system

http://www.amtrade.com/pc_power/dc_to_dc_power_supplies.htm

wants 238.00 US for a 12 VDC atx supply

The mini-itx can be directly connected to a 12 volts source as the have an internal switcher , the external brick is a 120-240 vac to 12 VDC