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Hardware

Handling Systems Exposed to Extreme Temperatures? 55

Posted by Cliff from the for-those-with-mp3-PCs-in-their-cars dept.
NeoMagick asks: "I live in a rural town in the Pacific Northwest, and I'll soon be picking up a Shuttle system which will get mounted in the trunk of my car, and patched into probably an Alpine or Pyle in-dash LCD panel. This last week temperatures have gotten up to 105degF, and have been known to get to -10degF in the winters. I'm wondering if any /.ers have had issues with computers in cars in such extreme temperatures (overheating? freezing?), and if so what they did to solve such problems."
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Handling Systems Exposed to Extreme Temperatures? More

Handling Systems Exposed to Extreme Temperatures?

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  • Specifications (Score:2, Informative)

    by Cardhore ( 216574 )
    If you go to the manufacturer's website, the manufacturer who makes the component(s), you can find not only a maximum, but also a minimum temperature at which that component can operate at! For example, an AMD Athlon can usually operate up to 95 degrees celcius.
    • You should also remember that these are the same type of people who say Windows XP will run fine on a P166MMX (bus speed 600mhz).

      Although there are parts that are designed for temperature variance (the EPIA mini IPX mobo) they're still the same basic concept and a good heatsink/fan will be more moderate.

  • Build an air box around the Shuttle's case, and blow cold or warm air into it from the car's cabin, or from one of the A/C-heating output ducts. If you're lucky, your car has ducts and controls for the backseat passengers. You might be able to route it under the rear passenger seats, for a minimalist "case mod." ;)
    • I'll probably get modded down for this, but...

      How exactly is this supposed to help when the car is not in operation? The poster above obviously doesn't live in a very cold climate.

      I live in Montana. It's not unheard of (or even unexpected) to have a week of weather where we don't get above zero (Farenheight) during the winter. I remember one winter where I had a half inch of ice accumulation on the floor under the driver's feet because of the snow being tracked in and then not being able to get the car hot enough to melt it during the short drive to work each day.

      -40 F is not uncommon to see during the winter months.

      At that temperature, things don't like to work at all.

      That said, if it were me, I'd probably just try it and see if I had any problems. If I had cold-related problems, I might consider adding some sort of very small resistive heater to the case and hook it up so when I plug in the block heater in, it also turns on.

      I'm the tech guy for a Wireless ISP, and when we mount equipment outside, we generally will buy a box with a small resistive heater element and a thermostat in it to turn it on when the box gets below 50-60 or so.

      • intersting fact you're probably aready aware of, but -40c and -40f are equal.

        so do ford or chevy trucks work better in the extreme cold? or does everyone use synthetic oil/block heaters so it doesn't really matter?

      • How exactly is this supposed to help when the car is not in operation? The poster above obviously doesn't live in a very cold climate.

        You solve it the same way those of us who work in the industrial world do it.

        If it's too hot, you ventilate if you can, and barring that put in a heat exchanger. If it's too cold you install a heater. You're going to need a power source for this some way or another (I never said the solution was pretty).

        A cheaper way to solve this would be to use a thermistor or thermal cutout which would kill power or at the very least signal an alarm if the temp got too high. You could use a low-temp switch to do the same thing. With some sequencing you could even turn on a heater and wait until the temp hit operating range before powering up.

      • How exactly is this supposed to help when the car is not in operation?
        Doesn't matter. If the car isn't in operation, the computer won't be running either, will it?
      • Um, why put a solar panel on the back dash and use that when the car is not in operation?
      • Running both a computer (200-300 watts) and a resistive heater or a cooler will drain the battery right quick. If you're gonna do it, this company makes many small, embeddable resistive heater components, but you'll need some way to distribute the heat, as many of these are relatively small and hot. http://www.tempco-electric.com/BODYPAGES/Tempco3.h tml

        Police cars are loaded with electronic gear, and their alternators are always engaging -the alternator and its belt usually go bad before the A/C or power steering pump (I used to work in a shop that serviced cop cars.)

        Heating the unit can be essentially free -while the vehical is in operation, as internal combustion engines waste most of the fuel energy as heat. Cooling costs, but with ducting at least you're taking it from a source that already exists, not having to monkey a new system together. (I couldn't find semiconductor-based refrigeration systems on the web, but I'm not sure what you call them!)
        • I couldn't find semiconductor-based refrigeration systems on the web, but I'm not sure what you call them!

          Peltier Junction
        • I've had to measure loads for battery calculations on systems which run off solar. A monitor typically draws 100-120 watts but even a fully loaded PC with a RAID only draws about 30 watts continuously (~50 startup surge). A PC which is already designed to be low-power and which only has one drive is going to be closer to 20w.
          But yes, even with the PC off a heater will still drain the battery...

  • You'll find out. (Score:3, Informative)

    by woolie ( 187633 ) on Tuesday July 23, 2002 @01:34AM (#3935404)
    I work with hardware designed for extreme temperatures. As far as I can tell, these are the prime considerations.

    1) Mechanical failure due to thermal expansion and contraction. This tends to affect connectors and plugs. Systems with poorly affixed memory components sometimes experience problems.

    2) Dissipation of excess heat. A modest external temperature of 35C may produce a temperature in your trunk of over 45C. At 45C, the CPU will have a hard time dissipating heat since heat diffusion requires a gradient. CPUs may tend to fail around 55C.

    3) Condensation. As you open and close the trunk in cooler weather, you'll be adding moisture to the closed space. Like dew, moisture will condense out of the air as components cool. Moisture on electronics tends to be less than optimal.

    4) Vibration. Automobiles are notoriously hard on electrical components because of the constant vibration. Single strand wire tends to fatigue. Connectors shake loose. There are mounting methods for abating shock and vibration.

    The systems we use for extreme temperatures do not sport contemporary CPUs because of the heat problems. To cope with condensation, we place desiccants inside the enclosures.
    • Regarding heat dissipation-- the problem will be worse since there is minimal airflow in the trunk, and the solar load (especially for dark colored cars) will actually make the internal temperature warmer than the air temperature!

      I wouldn't worry too much about condensation, since as the space heats up the relative humidity will drop. Of course the silica gel is always a good, cheap solution, though. (Be sure you can replace/refresh it, though!)

  • My experience (Score:3, Informative)

    by Dr. Bent ( 533421 ) <<ben> <at> <int.com>> on Tuesday July 23, 2002 @02:10AM (#3935501) Homepage
    I have a PIII 600 in my car, and I live in Houston, so heat was a big issue in my design. Here's what I learned:

    1) You MUST put everything heat sensitive in the trunk. The windows of your car act like a greenhouse, making the cab much hotter than the air outside. The trunk will usually be no hotter than the outside air

    2) It helps not to have a black car.

    3) Add as many fans as you can...and point them all blowing out of the case to try and reduce the pressure inside.

    4) Check the operating temps on your CPU and Hard Drive. If they're not up to snuff, consider replacing them.

    5) If you have a metal bottom in the trunk, you can use it as a heat sink. Just get a metal case and bolt it on there with some thermal paste between the joints. That metal will get fairly cool if you're going along at 70mph.

    6) This is not a heat issue, but I'd recommend mounting your HD vertically. That way, when you hit a bump, the RW heads don't smack into the HD platter.

    And if all else fails, buy a Peltier cooling unit and build a mini-air conditioner. I've never tried this (never had to) but it's my backup plan in case it ever gets too hot.
    • 3) Add as many fans as you can...and point them all blowing out of the case to try and reduce the pressure inside.

      why? does it help with the extreme humidity or somthihng?

      5) If you have a metal bottom in the trunk, you can use it as a heat sink. Just get a metal case and bolt it on there with some thermal paste between the joints. That metal will get fairly cool if you're going along at 70mph.doesn't that introduce just a horrendous amount of vibration into the system? or do you uber-shock mount the hard drive?

      i guess your system is working if you have the experience to give advice on it. do you use it primarily for mp3 playing?

    • Re:My experience (Score:3, Insightful)

      by schnurble ( 16727 )
      3) Add as many fans as you can...and point them all blowing out of the case to try and reduce the pressure inside.

      Actually, what you want is to point some of them out, and some of them -in-, and create a constant flow of air through the system.

      Make sure there are -lots- of air vents so you can move monster amounts of air through the system, and make sure you have equal capacity of fans sucking air in as you do blowing air out. "Depressurizing" the system (to the minor extent that your average case fan will do, anyway) is bad. Heat exchange requires something to dissipate heat into. If you thin the air, you dissipate less heat.

      If all you do is try to "depressurize" the system, you may not only damage the CPU by not cooling it sufficiently, but you might also put an unnecessary strain on your cooling fans, that are constantly laboring to suck air out.
    • Underclock and volt mod (lower) the CPU. Do the same thing for memory.
  • Plenty of 12 volt power.

    Lots of fan noise in the trunk is OK.

    The new shuttles have beautiful copper heat pipes that are begging for monster automotive airflow.

    Think BIG [fluidyne.com]. 9 inch diameter 600 cfm should be fine

    Do NOT forget a filter. Try a Hepa home air conditioning filter.

    Do not recirculate the already hot air in your trunk. Use NACA ducts [recumbents.com]

  • Here is what you want VIA EPIA Mini ITX Mainboard [viavpsd.com] Get the one with the Eden ESP 5000 processor, and it needs zero active cooling and pulls under 6 watts
    Some people may complain about divix or DVD playback - from what I read, that is a legit gripe with the onboard video which shares main memory. It will play MP3s just fine. If you need high speed video, add in a hither end (but still passive cooling) PCI card.

    It comes with onboard video, sound and networking. The video has TV-Out w/ Integrated Macro Vision 7.01, S-Video or Composite video output, Supports NTSC/PAL TV formats. Via has a link on the site to places that cary them

    I haven't bought from them so YMMV; I'm looking at idot.com [idot.com] to get one to replace my mail file-server at home, since I hate fan noise, and burning power 24x7.
  • I would reccomend you take a look at http://www.mp3car.com message boards, there is more information there than you can shake a stick at on heating and cooling issues. Many people have had problems with tempature extremes on their boards. The problem does not seem to be with the exreme tempatures themselves, but rather with the fact that cars heat up/cool down quickly and often.

    It is a great idea to use plenty of fans if possible, but even cooler (pun intended) is to use you car's body as a giant heat sink for your power supply/chip. Should't be too hard to be creative in car setups, there is lots of innovation to be made. Check the forums on mp3 car to see some good examples.
  • You think your car can get hot? Try trying to run a switch/router/etc in a metal enclosure 200 feet up on a grain elevator in the texas panhandle. 75% of the year, the metal will be either too hot to touch or have about 1" of ice coating it. Generally the cold is not a problem as the components (as long as they dont actually stop running) keep everything warm enough not to have any low-temp problems. The heat is another story.

    Since the box must be sealed to the weather, we have to use heat exchangers -- they are devices that mount through the sidewall of the box. They come in varietys that range from what amounts to huge peltiers when air cannot possibly be exchanged all the way down to what amounts to very tiny split system air conditioners. They're fairly expensive to run when it gets really hot, but they will cool the inside.

    The main problem you're going to have in your car is the initial startup of your electronics. Your trunk is going to have no love from your car's climate control systems. Hence if it's 110 or -20 degrees outside and your car sits out for 8 hours while you are at work, *everything* in the trunk will reach the ambient temp. So, you might have to pre-heat your computer case in the winter or pre-cool it in the summer even before starting.

  • Hard drives (Score:4, Informative)

    by adolf ( 21054 ) <flodadolf@gmail.com> on Tuesday July 23, 2002 @03:15AM (#3935645) Journal
    The component most likely to complain about temperature and vibration is the hard drive.

    While your car's suspension will work rather well at isolating things from bumps in the road, it wouldn't hurt to get a little creative with mounting the drive. Suspending it between rubber straps might be a good idea, but watch out for things which are bouncy (resonant) -- it almost doesn't matter how much of the initial impact that your suspension absorbs, if it continues to shake the hell out of the thing several seconds after stuff should've come to a rest.

    Hard drives come packed in open-cell foam, like a mattress pad, and seem to survive UPS Ground pretty well in such an arrangement. It wouldn't take too much creative engineering to fabricate an enclosure made predominately out of foam, but with a fan and enough room for air to circulate.

    Temperature doesn't look like it's too much of a hassle, these days. I'm looking at the specs [ibm.com] on an IBM 120GXP, which show it to be happy from -40 to 55 degrees celsius (-40 to 131 F). Since these are ambient temperatures, the drive is thus designed to withstand a trunk at 131 degrees with moderate airflow.

    Since you'll be opening your windows and/or turning on the air conditioning Right Away on such blazing hot days, the hard drive should start recieving cooler ambient air at about the same time it starts generating appreciable heat of its own.

    And in the winter, at -40, the last thing you're worried about is whether your hard drive will spin up. More important is whether or not the engine will, and if you'll be able to get the tires un-frozen from the ground. If you've got half a brain about you, you'll have the computer and stereo off, anyway, until the car is well under its own power...and, by that point, generating heat to warm up the electronics.

    I'd avoid connecting the enclosure directly to the car's ductwork. Ever see a windshield fog up on the inside on a cold morning, just after you turn on the defroster? Imagine that happening to your in-car PC. Bad news. :-/

    Since the motherboard you've chosen is so bloody small, have you considered putting it under the front seat? Things would get impossibly tight in a sports car with power seats, but should be do-able in almost anything else. There's no reason for the box to be more than an inch or three high. Sescom is a company who makes a large variety of metal boxes for do-it-yourself projects - chances are, one of them would fit your motherboard, hard drive, and some manner of DC power supply justabout perfectly, while remaining small enough to slide under the seat.

    Drill or punch holes in the sides of the box, and mount the biggest, lowest-RPM fan you can find on the top of the box, blowing down. You might even be able to do away with having a dedicated CPU fan, and get by with a just large heatsink.

    There's a few other things you might want to look into, with software. There's a way to poll hard drive temperature using a protocol called SMART - if the drive is cold, keep it spun up to reduce the viscosity of the grease in its bearings. Likewise, if the drive is fairly warm, spin it down when not needed to reduce wear and help ward off data loss (they are, of course, -much- more durable with not spinning).

    Do the same with the CPU, if it suits you. If it's cold out, run the CPU full-tilt (seti@home, some random busyloop, cat /dev/zero > /dev/null, or whatever) to keep the motherboard components warm and well within design spec, which will help reduce condensation. Do the opposite on hot days - HLT the CPU when idle, so as not to make things any warmer than needed to get the job done, and take whatever other power-saving measures you can.

    The goal here is to bring the board to some desired operating temperature, and keep it there until the car turns off.

    All that said, you'll probably find that the most sensitive component of your system is the LCD display, which will be painfully slow/frozen on cold mornings, and either solid white or black after a hot day of sitting in the sun...and there's really not much to be done about it, unfortunately.

    good luck!
  • I thought many of the overclockers would kill to get a system down to -10 degrees. I'd only be worried about it heating up, and even then my opinion would be if a human can stand it it should be ok for a computer (but still have a good heat sink and good ventilation)

  • Computers freezing in cold mountin' country (Score:1, Funny)

    by Anonymous Coward
    temperatures (overheating? freezing?),
    "Hey Jethro, this here computer has frozen solid`"
    "The manual says to reboot the new fangled thing Jeth"
    "Alright, I'll kick it with ma boot"
    ::boots the frozen computer, ice breaks off::
    "See that is a how it's done, now it works again"
    • I have oft wondered why more data centers aren't located in the mountains, if filters or heat exchangers were placed on the building in the winter you wouldn't have to cool the building. In the summer you would still have to, but a geothermal heat pump is really quite efficient. Additionally Touch America and Qwest spent plenty of cash laying fiber everywhere, I can't imagine much of it is anywhere near capacity, and it should be pretty cheap.
      While Jethro might not be the ideal tech, there are plenty of sharp sys admins here in Montana, and most of them are happy to stay here.

  • shutting down? (Score:3, Interesting)

    by paradesign ( 561561 ) on Tuesday July 23, 2002 @09:21AM (#3936588) Homepage
    do you have to remember to shut down the stystem everytime you shut off the car. it could get annoying if every time you had to wait 30 sec to fully kill vehicle power.

    on the other hand, if it could run with out the ignition being on, how fast would it drain the battery?

    would there be any way to write a script that automaticly shuts down correcctly the system when you shut off the car. I know there are systems for turbos that do a simmilar thing. when you shut down a turbo automobile, especially if you have been driving hard, you are supposed to let the engine idle for 2-5 minutes before killing power. this is to let the hot oil out of the turbo and let every thing cool down properly. there aare turbo timers that continue to run your engine for a desired length of time without a key in the ignition, shutting it off for you. this lets you get out of your car and get on with your day without waiting around for your turbo.

    could a similar system be adapted to shut down your automotive pc? how do people deal with this now?

    i am interested in doing something similar now, and the shut down prodedure is my main concern.

    • I use this [astron.nl].
    • Try using this: http://home.attbi.com/~zootjeff/shutdown/

      THis guy has produced a great atx shutdown that will time out (adjustable) the time between when you kill your ignition and when it sends a "push power button" signal to the mobo. Much easier than a software script, plus you can buy them from him for around $20. Good luck!
    • I use
      this [chargeguard.com]

      Originally designed for commercial radios, it works great for me. You can set the turn off delay from 15 minutes to 15 hours.
      Kinda expensive at $75 (I got mine free as a demo) but it also provides high, low and reverse voltage protection and will handle 30 Amps.
  • Dan's Data (www.dansdata.com) had a very nice review of the Via C3 - basically, it's pretty damn slow, but does not generate much heat at all. If all you want is an MP3 player or some other application that doesn't need a whole lot of grunt, this may be the thing for you.
  • I live in an area of the country where temperature extermes are a way of life. I'm planning on doing this as well and I'm planning on putting the whole system in a modified coleman electric cooler [coleman.com]. This unit, can heat the contents, or cool the contents, depending on the polarity to the peltier device. I would also add a vent with flaps that could be automatically closed and opened. A temperature sensing circuit would then measure inside and outside temperature to determine how to best vent/heat/cool the box. It would also provide a thermal shutdown feature.
    Of course this is all "planned" so the chances of me actually building this might be slim :-)
  • I've gotten my empeg up to 145 deg F and it still seems to work fine.

    The empeg though can shutdown on over-temp if I choose to though. I'm jsut going to route some AC to the bay though.

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