FAQ: How do climate extremes affect a Car PC?

**h3rk** · 11-01-2006, 06:40 AM

Ecxellent FAQ Bugbyte! I made it here searching various things like dessicant, condensation, air conditioning...(much more). I think I have seen, by far most of what this forum has so far on the issue of heat/cooling. It is good to know that many people are having no problems operating their carpc's in very high temps. I have seen all of the posts warning of condensation, and now understand some of the cold climate related problems we face.

I am going to go against the better judgement

Uh Uh Uh, You didn't say the magic word !

of many here and use climate control, Mastero's aircon2 (thread) (soon to be released as of yet, I hope) and some automation to cool my rig. I have yet to read any bona-fide horror stories. Please, if someone knows of any please let me know. I plan to do some testing on the matter, a sceintific as possible (I understand the whole 'build specific' thing and I all I can say is I will do my best, if only for uATX people). I'm thinking some humidity sensors and MOBO + additional Temp sensors, some 24/7 action, some extreme climate, and some datalogging.

The plan is to have the carpc know when to start up the car to either heat or cool the computer compartment when temps get too high or too low (as well as the obvious charging needs). I think I'll be ready in time to do some winter testing (I'm not in the most ideal climate for that, deserts do get chilly), but definately stay tuned for summer.
I haven't posted my setup in my sig yet (still coming together on the bench), but it's a uATX mobo, AM2 sempron 3200 (I may even be persuaded

to overclock, and undervolt for more data), DSATX P/S using onboard graphics, Audigy ZS2 platinum pro, additional average-setup periphs (HQCT, 60G FDB style hard drive), eclosed slot drive...blah, blah, soon an aircon2, and phidgets (I/O) on the way, all going in the computer 'case'.

Lemme know if this interests anyone even a little, or if you have any ideas to make the tests more complete or scientific. I'll start a new thread on the plan within this month, and update with a link here when I do so.

I love this stuff. Heat transfer, PV/T, saturation curves, who would have thought I'd be using this stuff in a computer 'case'. (ok, maybe heat transfer)

**afterdigital** · 11-03-2006, 09:23 AM

the LCD not initially working at first in the winter makes sense. This occurs to me every morning i get in my car. Thanks for the heads up. I began worrying that there was something wrong.

Only thing is now i am considering getting a remote start - $200 bucks ouch.

**turbocad6** · 11-03-2006, 09:50 AM

just a bit on the ac cooling issue....

the problem is NOT by cooling the pc with the ac.... this WILL WORK FINE......

that's not the problem.... cooling the hot pc components wil have NO ill effects....

the problem comes when that ac goes away.... turn off the ac, park the car... now the computer components are below ambient, which will rise quickly on a hot day.... THIS is where the condensation comes in, & let me tell you, it can get bad enough that the components wil actually be WET..... like taking a can of coke out of the fridge & placing it on a table on a warm day... it will become WET rather quickly with condensation.....

restart the car a bit later, everything is damp.... can you say short circiut

....

ac cooling will only work if you can control the temperature rise after the fact, & you really can't..... in a house where it's running all the time, no problem... in a car, if you have the pc chilled, then get stuck in bumper to bumper traffic, turn off the ac & open the windows.... the pc WILL short out.... this is not a hypothossis, this is a FACT.... I have tested this method & know first hand.... don't do it, not a good design...

**afterdigital** · 11-03-2006, 10:13 AM

uhh, so don't turn the AC on?

**turbocad6** · 11-03-2006, 10:46 AM

no, don't duct ac cold air directly to the pc for cooling

**afterdigital** · 11-04-2006, 04:05 PM

thanks for the recommendation. i was actually thinkin about doing exactly that. now i know not to...

thanks

**h3rk** · 11-04-2006, 11:49 PM

Thanks for sharing the empirical information, turbocad6. That is very useful. I would have surely fried some stuff.

What if the computer had a climate controller that never allowed the cooling air to get too cold (by using its own heater/temp control door)? It can use RH sensor & temp sensors to select, from mapped data, a temperature that is closer to ambient; close enough to preclude condensation. Then the metal components of the computer will not 'chill'. I know there is an abundance of dew-point and related data that would be helpful. This system would benefit from being sealed when not being cooled by its fancy climate control (but that would be tough). And timing the puter to remain on longer than the cooling system, long enough for temps to rise above ambient (or until triggered by sensors/ setpoints), would negate ill effects of the chilled components with warm damp air (to that of at least more normal arrrangements).

**afterdigital** · 11-05-2006, 12:43 PM

what i'm thinking is install a fan or two in the pc area sealed to a long enough tube which can direct the air within to blow out to the cabin of the car.

**turbocad6** · 11-05-2006, 01:33 PM

the idea is not to bring the metal temps too far below ambient air temp... if you measure the temperature of the air coming out of an ac vent on max in a good system, yyou'll see a temperature of 35-40 deg f.... if you do a good job of using the ac, you can get metal temps down in the 45 deg range.... when the cooling goes away, & the air temp around the metal hit 90+ on a hot day is where the problems come....

ac can be used if you control the flow... IE; a temp sensor that controls a blower.... temps over threashold A, fan on, but, whwen temp goes below B, fan off... this can be really effective....

an alternative may be to usejust a slight amount of air... not enough to cool very efectively, but enough to just lower case temps a bit....

**weekendowel** · 11-07-2006, 12:13 PM

I live in Sweden and we get temperatures as low as -25 C (-13 F) and I actually had to make a small electronic circiut to press the reset button on my PC every 5 minutes if it didn't recieve an acknowledge from the comport, that means if the PC got stuck on the "Boot drive failure" it automatically reseted until it got so warm it was able to start which in most cases only required one reboot.