FAQ: How do climate extremes affect a Car PC?

Bugbyte · 10-30-2005, 02:45 PM

Around Fall and Spring the question of how climate extremes affect Car PC's begins to come up.

Winter

In general, Car PC's are remarkably resilient when it comes to dealing with low temperatures that the majority of members are used to dealing with (down to around 0 degrees F or -17 C).

However, cold can and does affect the LCD screen and disk drive. LCD's are liquid crystal devices which can freeze if the temperature goes low enough. In addition, the fluorescent tube that provides the backlight to the screen (called a CCFL) can be dimmer due to the cold.

Both the LCD and the CCFL generally recover as they warm up and will operate normally afterwards. It is not clear whether this shortens the life of either component as we don't have any data from comparison testing.

Disk drives can also be affected by the cold. First, there are two types of disk drives. One uses ball bearings and a race around the shaft of the drive. The other uses fluid dynamic bearings (FDB), rather than the ball bearings. FDB drives are almost always used in laptops and have the advantage of lower noise and the ability to spin at higher speeds.

Mechanical disk drives with bearings seem to survive extremely low temperatures better than the FDB drives. As the temperature approaches single digits farenheit (around -12 C), the fluid in the bearings thickens and the drive platter cannot spin at the appropriate speed. This can cause a boot failure. This suggests that if you live in an extremely cold climate and intend to use a disk drive, you should choose a drive with ball bearings for best performance when cold.

In almost all cases, members have reported that their FDB drives returned to normal operation after just a few minutes in a warm environment. If the drive is inside the computer case, the heat from the processor will often warm it up and a reboot can be accomplished.

Threads on Winter:
Climate?
Extreme cold
Car PC in winter
Does the cold affect my system?
Hard disk life expectancy in cold

Search terms: Cold, Hard Drive, LCD

Summer

Most Car PC's are operable in high heat environments (up to 110 F or 43 C). Since processors usually operate at such temperatures when warmed up, there is usually no issue with operating your Car PC at these temperatures.

However, the temperature in a closed car in such an environment can soar to 150 F (65 C), far above normal for a Car PC. If the PC is in an enclosed location such as a dashboard, simply opening the doors of the car, causing it to cool it off by 30 degrees or so may not cool off the enclosure that the Car PC is in.

Temperarture monitoring software such as motherboard monitor is useful in this situation to ensure the PC shuts down if the fans or the incoming air is not sufficient to cool it.

Most members advise against directing air conditioned air into the PC case due to the possibility of condensation forming inside the case. Likewise, attempts to direct outside air into the car are also advised against as the temperature of the air above the road is likely higher than the temperature that a PC would intake from the passenger cabin.

Threads on cooling:

Cooling of a different kind
WizardPC's cooling thread

DJiK · 10-30-2005, 03:51 PM

Summer & LCDs:

I just wanted to briefly add that my TView 700TS acts up when the car is hot during the summer.
It tends to white-out (display a bright white image) whenever it's hot. To fix that problem I have to cut the power to it off and back on (the actual power cable, not the button).

schpanky · 10-31-2005, 10:47 AM

I appreciate this thread now that the chilling winter months are settling in and I was wondering if I should just take the hdd and lcd out during this season (I'm storing my car this winter, mustang + snow =

)

This thread confirms it, thanks a lot.

DaPCWiz · 11-01-2005, 12:49 PM

my dynamix 706 seems to act up when it gets cold out. It won't turn on at all for like 2-3 minutes. Then after I flick the power on and off a few times (a switch I wired to the + wire) it comes on and works fine for the rest of the day... unless it gets a chance to get cold again.

Weatherboy · 11-12-2005, 12:13 AM

I just read up on the BB and FDB drives and when i read the specs for the BB they say 5°C is the low temp and the FDB say 0°C has anyone tested the BB to see if it works better than the FDB?

Bugbyte · 11-12-2005, 12:25 AM

The BB aren't affected by freezing of the bearings. You'll see people with FDB's posting that they don't work when it gets cold while people with BB's don't.

fliplap · 11-28-2005, 02:47 PM

Indeed, my laptop drive has been having trouble on the really cold mornings. It can take 2 or 3 trys to get it to boot. It will freeze in the middle of returning from hibernation. After the drive has been spinning for a minute or so its good to go.

Wiredwrx · 12-01-2005, 04:25 PM

Since there have been a spate of postings about this,

Many people have done the "auto on mod" for their lilliput. This auto on uses an RC circuit to "press the button" to turn on the screen. However, most Caps have a temperature range. Below this range, the characteristics of the component changes. Most Caps used are Electrolytic, which generally uses a liquid electrolyte. Because of this, in cold, particularly extreme cold temperatures, the liquid is less effective, and the RC circuit will not act correctly. You can try and locate better Capacitors, that will work in the extreme cold. Glass is probably the best known extreme cold Cap (they use them at Nasa and in the Military) but they are difficult to locate, and quite expensive. I know of one manufacturer (http://www.avxcorp.com/) but I can't find a place to get them.

Another result of extreme cold is, dare I say it, shrinkage. Everything will shrink/contract in cold conditions. You may not ntoice it, but even the plastic in your car will shrink/contract ever so slightly in the extreme cold. Of course, if you screen in mounted molded into your dash, the shrinking dash may have adverse effects on your screen, and in particular, the TS. Of course the plastic sheets of your TS can also shrink, and in particular, if you sheet shrinks more then the other, or they shrink differently, that can cause the sheets to touch, making the TS operate erratically. The only real solution for this is to heat up the interior of your car before you start the computer. You can just wait for it to warm up when you get in it, or perhaps use a remote start to do it, but other then waiting for the car to heat up, there is nothing you can do.

Michael

Ko_deZ · 12-15-2005, 09:07 PM

Quote: Originally Posted by Bugbyte

Most members advise against directing air conditioned air into the PC case due to the possibility of condensation forming inside the case. Likewise, attempts to direct outside air into the car are also advised against as the temperature of the air above the road is likely higher than the temperature that a PC would intake from the passenger cabin.

This is not correct. The only place you get condensation is places where warm air hits cold objects. The physics here makes the air go from warm to cold, and by doing so reduces the ammount of moisture it can contain. If the air is cooled down enough, the air cannot keep the moisture anymore, and you get condensation. Cold air hitting warmer objects will never cause condensation (except extremely hight speeds that cause preasure fall behind objects. We're talking jet planes here...)

This is by the way the reason for the AC to leave a puddle of water under the car. The air is cooled down by the AC, and by doing so, the water condenses there. If this was not the case, you should get condensation on your windscreen when using AC in the heat. I bet that never happened

-Ko_deZ-

Bugbyte · 12-15-2005, 09:33 PM

I believe the theory is that the case is filled with warm, moist air that fills it from the outside. When the cool air fills the case from the A/C, it gives up the moisture.

Ko_deZ · 12-16-2005, 06:07 AM

After what I can remember, the mixing of the two air parts (the cold and the hot) will give a new air temperature relative to the two parts of air's mass and initial temperature. The resulting air mixture (this is how i remember it) will allways be capable of holding the same ammount of water, which means, that some of the moisture will travel from the hot airmass to the cold airmass as an result of mixing them and evening out the temperature.

This is not the same as how clouds are born, as that includes pressure change.

-Ko_deZ-

lez · 12-16-2005, 01:08 PM

Lol, mummy clouds......

HitLines · 12-18-2005, 03:26 AM

What are same model numbers of drives that don't use fluid dynamic bearings? Newegg does not always list this information.

carabuser · 12-18-2005, 03:35 AM

Summer & LCDs Part II

When I used to have my Lilliput TS working in its case, touchscreen would stop wokring after a little while during hot days as the whole monitor got hot. Turning off and on the screen would NOT help. Only solution was to restart the system, which makes me suspect that there's an issue with the TS controller. Since I took this thing apart and mounted the screen into the dash without the case, leaving some space between the LCD panel and the board, I no longer have this issue.

flyingwil · 01-15-2006, 06:20 PM

I was wondering how the extreme heat in Las Vegas and Phoenix affects the PC's, with it being 117 outside for months and one incident of leaving the windows up with no windowshade, could easily get temps inside the vehicle of 150*...

Any one from these areas?