i wasn't sure where this one should go since there is no hardware section. i've been looking into mini itx boards to build a small, portable computer that's efficient on power. the only set back is a power source, so i was wondering if anyone here has ever used a battery (car, lithium ion, any type) to power a mini itx box. the entire box would use like 80-120w i would say. from what i've gathered a car battery should work if you use a few other pieces of equipment.

anyone got experience with home brew projects like this? 

Hey Indi -

I built a mini-itx (I thought it was ATX, but I may be mistaken) on the back of a flat-screen monitor a bit ago for a wall mount, self contained computer. Wound up working pretty nicely - used a notebook hard drive (notebook -> IDE adapter) and a mini power supply that hooked right on to the board - it hooked up to a converter brick... - as I remember it was a 12 volt converter, so I think that you'd be in easy with something like that.

I did this from a Popular Science article I read a couple years back - it might still be findable. I'd imagine that car battery would be WAY more than ample, since the wattage required is so low.

i'll have to look around old PS articles, thanks perk. i figured a car battery would work well, should be able to stay on for a few days before the juice runs out. the only downside of using a car battery is the weight, so maybe a lithium ion battery would be better as long as it can last for a few days.

I saw this (yesterday i think) mini computer which uses 8 watts of power and can run on a solar panel.

http://www.gadgettastic.com/2007/11/29/tiny-

linux

 -pc-uses-just-18-watts-power-can-be-solar-powered-the-aleutia-e1/

yes i saw this too, this is what originally set me off looking for more information. years ago i had come up with a few interesting home brew projects i'd like to do with itx boards, i just never got around to planning them out or doing them. recently however i've got a real use/need for one of these projects to be completed, and coming across this article gave me a moment

solar may be a good option, though it would be limited in that it would need a clear view of the sun to get power (i think?). it would also be less portable placement-wise due to this requirement, however using a long cable to place the solar panel further from the actual box may be an option.

for these two reasons i'm leaning towards using a battery. although having solar and a battery might be the best bet, granted the battery can be charged by the solar panel.

I don't really know much about solar power but I'd guess its like using a pigtail cable for your wifi antenna.. the longer the cable the more loss. You could have it on some kind of battery/solar system where the batteries are trickle charged. Meh I dunno, you gonna tune them into someones home wireless and hide the box in their bush?

yeah i thought the juice might get weak over distance, which makes things trickier. i know there's a solution out there 

You will get a voltage drop over distance, but you can offset this (somewhat) with larger diameter wire.  Smaller diameter wires and higher temperatures increase resistance.  Increasing resistance means more voltage drop.

h++p://howto.altenergystore.com/Reference-Materials/How-to-Size-Wiring-and-Cabling-for-Your-System/a62/

=RT=

Speaking of higher temps...I think when I peltier cooled my celeron 700Mhz back in college with a water cooler cooling the peltier, it was faster than most of the dual cores I've been playing with lately. I mean it was ridiculously fast, and -10 degrees C running under a full load or playing a graphics-intensive game.

Sweeeet.

It made my pants tight.

I'm nursing a semi

I usually let my lady friends to the nursing, but hey - whatever twists your nips man...  :

vsloathe::

Can you tell me exactly how you cooled the 700mhz pIII with
a water cooler?  would love to try that.



well car batteries are 12volts and the amps depend on the battery, but all
of the stuff inside a standard box or laptop should run on 12v 500ma, exactly
the same voltage that is coming out of your standard (20fused) cigarette lighter.
(Of course i have some 12 awg lamp wire (2$ extension cord + scissors) coming
straight off my battery into a 30a fuse for more amp ability...guess i could have
spend 15$ on that roll of AUTO WIRE but copper is copper man! and by saving 13$
i got better awg that can handle a higher load).

Those little four prong connectors that hook into the back
of  a standard IDE hard drive or cd rom player/burner have  -5v,+12v,-12v and +5v
im sure i have the order screwed up and it DOES matter!

so as long as your not needing that 5v wire.......... just make sure or get
some transformers...  and some fuses

A running laptop uses between 50w and 70w...

RC is the number of minutes a fully charged battery at 80° F can be discharged at a constant 25 amps until the voltage falls below 10.5 volts. Deep cycle batteries are usually rated in Amp Hours (AH). To convert RC to Amp Hours (or AH to RC), check the battery manufacturer's capacity specifications. More RC (or AH) is better in every case. In a hot climate, if your car has a 360 OEM cold cranking amps requirement, then a 400 C CA rated battery with 120 minutes of RC and more electrolyte for cooling would be more desirable than one with 600 CCA with 90 minutes of RC. There is also a relationship between the weight of the battery and the amount of RC (or AH). The heavier the battery, the more lead it has and potentially a longer service life.

Once you get the amp hours, then you can do the math based on a 50-70w draw remembering
algebra I and that Volts x amps = watts.....

i can go almost two hours running my laptop off of a deep cycle marine battery i lug around...

I would suggest an array of deep cycle marine batteries charged up by solar panels,
wind some  copper wire around some ma

gnet

 s and make a wind powered generator,
then buy a shed in a box from costco for 500$ and fill it with hamsters,
get a power take off of the hamster wheels, get physics book out and transfer
the motion to yet another alternator and have all that running to an array of deep cycle
marine batteries..  OFF THE GRID, BABY!

unlesss you want to pressurize some ' jenkem ' and run that in a propane modified engine....  

im REALLY into the off the grid and dinosaur fart stuff, an interesting link if you are too: http://coolfuelroadtrip.com/technology.htm

Well, I bought a copper water block, I think from coolerguys or frozencpu. I went to Wal Mart and bought a 1-gallon Rubbermaid jug, I went to Home Depot and bought about 20 feet (way overkill but I wanted enough) of flexible clear plastic tubing, several grommets and hose barbs, hose clamps, etc. I went to PetCo (or some pet store) and bought a 50GPH submersible fish tank pump. I went to a junkyard and yanked the heater core and transmission cooler out of an old Saab 900.

I assembled this all together, cooling the heater core and tranny cooler with 120MM PC fans running off a separate power supply. I used the passthrough of the power supply to power the fish tank pump which ran the contraption.

I mounted the copper water block on a peltier device and then I mounted the peltier device on top of a solid copper block so it was sandwiched with the cold side on the solid copper block and the hot side on the copper water block. I insulated the SHIT out of everything with 1/4" neoprene and polystyrene foam. I used plumbing caulk to seal up the neoprene. I mounted all this on the die of my 700Mhz celeron chip, unlocked the multiplier and started cranking it up. I was running 1.33Ghz stable at ~-10 degrees C full load.

Granted they make water cooled kits now and that makes it easier. My setup was rather large but extremely efficient. My computer looked like R2-D2 because I spot welded an extra case to the top of my already huge server chassis to house the water reservoir and cooling apparatus/air exchangers.

Man, I wish I still had some of that stuff to screw around with. I think my parents threw it all away when I was storing it at their house while travelling one summer. Lol.

The Perk is incredibly impressed. Nice work VS.

Lol thanks Perk.

I'd love to do it again someday. All these overclocking n00bs got nothing on the oldtimers. Before I got to college I had done a lot of work on cars and really enjoyed it, so I had some ideas for neat hardware like that. I also had a good friend who was very mechanically inclined, helped me design and piece together the whole thing. I'd have never found the junkyard if not for him.

The furthest I ever went with hardware was to wire up a Selectric typewriter to the enunciator port (plus a bit more) on an

Apple

  ][ so that when I pressed a key on the

Apple

  it struck on the Selectric. I was splooging all over as if I'd invented fishing penicillin. I love that stuff dearly but don't have the time for it... love to hear more stories.

Does anyone here read Make by O'Reilly? One of my favs

VS -->  yea, totally sweet! Technogyver!

I rewired my atari 2600 joystick for my left handed friend and
I made a two line telemarketing database dialer out of some 12v
relays, a dissected joystick, two hayes smartmodems
with the extended command sets, an old headset fone from the
seventies, a 486dx, half pack a smokes and microsoft qbasic....

Oreilly, eh?

Indeed, and it's quite good. Lotsa fun old-style hack projects for the unscriptkiddie in all of us