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Thread: GPS too hot in direct sunlight

  1. #1
    Constant Bitrate utd09bry's Avatar
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    GPS too hot in direct sunlight

    Hey everyone,

    I am posting just to share my recent experience.

    I have been battling startup problems when the car is very hot on the inside. I live in TX, which may not be the best place for a CarPC in the summer... but I decided to figure this crap out.

    The exact problem was: PC turns on... begins POST... shows Memory Test... and freezes before getting to IDE detection.

    After reading, researching, experimenting... I had narrowed it down to my GPS or my 5V PS rail in general. I found that by unplugging all my USB devices (hub, which was not externally powered) the computer would boot just fine. I managed to narrow it down to the GPS by adding devices until it failed again.

    So. Either my GPS was screwed up (only when hot?) or my 5V rail sucks (only when hot) or my GPS pulls the 5V rail down to far (when its hot).

    Headache!!!

    However, Problem solved

    First I tried giving the hub some extra juice. Tapped a 5V connection from my PS to the hub. No difference.

    Then, I decided to assume that it was my GPS, so I took it inside and let it come to cool room temperature for about an hour. Taking it back into the car, plugging it in, and booting... I found it WORKED! Over and over...

    One thing to note was that my GPS was previously mounted on my dashboard all the way forward under my windshield. And let me tell you... when I decided to take it out... it was HOT. Burning to the touch.

    I think I'll cut to the chase now, but I will add that to appease my curiosity I took some temperature readings in my car. One on the back bench which is shaded from direct sunlight, and one on my dash... right where the GPS was.

    Ambient Temp: 125F
    Dash Surface Temp: easily 150F+ (best estimate using a grill thermometer )

    I moved the GPS to one of my back windows that is tinted... and it has worked ever since.

    I wanted to put this out there in case anyone might be having the same or similar problem.

    If you are using GPS and are having boot problems in extreme heat... make sure the unit is not overheating!!! Get it out of the direct sunlight because it will easily push or exceed operating temperatures

    And thus ends my story.


  2. #2
    Fusion Brain Creator 2k1Toaster's Avatar
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    You are overloading the 5v rail as you found... The thing is that transistors vary with temperature. So yes heat has to do with it. Not only does the power supply become less efficient (gives less current on the 5v rail), but the devices pull more power to cover the increased inefficiencies. It is a compounding problem.

    Now this change is rather small. If it is enough to make your system instable, you are right on the edge of a dangerous cascading failure.

    Maybe a simple 5v supply to power your peripherals is all you need, but I would definately not suggest you leave it as is.
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  3. #3
    Newbie AnimeCommander's Avatar
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    Hmm. I plan on putting my GPS receiver right where yours (utd09bry's) was under the windshield. Now I'm in California, so it's not as bad as Texas, but this concerns me still. I will have a externally powered USB hub, but my receiver will be direct to the PC. The stock GPS receiver is on the back middle under the rear window. I'm trying to avoid running a cable all the way back there. What's the best way to avoid heat issues? I was just thinking of using a sun shield, but I know I'll forget.

  4. #4
    Constant Bitrate skeurton's Avatar
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    i'm having the same problem. i bought a new GPS receiver thinking that the heat killed my old one, but i'm still having problems with the new one (holux gr-213). on moderately warm to hot days, the pc will boot up just fine with all usb devices working (using powered hub). but streetdeck comes up with a message saying it can't find my GPS receiver. on cool days or at night, it boots up just fine.

    right now, the receiver is mounted on the rear deck. i don't have any window tinting, so the thing is in direct sunlight. i had no problems with my previous microsoft/pharos receiver being there for 3 years, that is until recently. i'm not quite sure how to solve this problem. i tried mounting it on the underside of the rear deck, but it wouldn't pick up a signal.

    anyone have any ideas?
    Mazda 6 Carputer

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  5. #5
    Constant Bitrate utd09bry's Avatar
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    Quote Originally Posted by skeurton View Post
    i'm having the same problem. i bought a new GPS receiver thinking that the heat killed my old one, but i'm still having problems with the new one (holux gr-213). on moderately warm to hot days, the pc will boot up just fine with all usb devices working (using powered hub). but streetdeck comes up with a message saying it can't find my GPS receiver. on cool days or at night, it boots up just fine.

    right now, the receiver is mounted on the rear deck. i don't have any window tinting, so the thing is in direct sunlight. i had no problems with my previous microsoft/pharos receiver being there for 3 years, that is until recently. i'm not quite sure how to solve this problem. i tried mounting it on the underside of the rear deck, but it wouldn't pick up a signal.

    anyone have any ideas?
    The operating temperature for the Holux (same one I have) is up to 80C, which is about 175F. Mine was coming pretty close to this temperature when it sat in direct sunlight for hours (also, outside air temp has been 90F+)..

    I considered powering the hub with a Point-of-Load supply.... but in one of my tests I plugged the hub into a wall outlet (extension cord dragged from my garage) so the 5V extra juice was not from the PC PS.... didn't make a difference. For some reason, the GPS still being connected to the PC power line (through USB) was enough to still cause problems.

    I wonder... can you use a USB hub that is connected ONLY to the data I/O connections (i.e. cover/remove power terminals from cable) and just use the external power (from a POL or similar isolated supply)?

    Oh, another something I had wondered. What are the chances that the GPS, being hot and possibly malfunctioning, is just spitting garbage at the PC through its USB IO and it causes it to freeze. I was beginning to think that my PC was possibly trying to read that input code as a boot device and getting confused. I would have disabled USB Legacy support to try to test this... but I need to find a PS2 keyboard to recover from that test (been using a USB keyboard). Thoughts on that? I know it's pretty far-fetched but I'm trying to consider anything here.

    UPDATE: been reading around tonight.. and if you search more in general online, this problem exists across the board for many devices. I'm really thinking that the reason it freezes before detecting IDE drives is because it is trying to check all the USB devices for boot capabilities (and the GPS is causing issues here). A common fix seems to be disabling USB legacy support. This way, the BIOS will ignore USB device functionality completely. Of course if you intend on changing anything after that you will need a PS2 keyboard handy. I'm going to try this out tomorrow to see what kind of results I get. Actually, I need to find a PS2 keyboard first but I'm sure I have one lying around here somewhere :-p

    Update Update:

    Couple things learned today (friday)

    USB Legacy Support (Disabled): Makes PC absolutely FLY through POST. Boot-ups are super fast and I don't have any startup problems.

    Lilliput Monitors: A warning to all (2k1Toaster, I saw you had this problem too!). Do not, under any circumstance use the auto-adjust button. Great idea... baaaaaad situation. My 800x600 functionality is fried. Yeah. SUCKS! fkljasdfl;kjslakfjlskaj

    So now I run in 1024x768 which I don't love but it works. Thank you roadrunner for scaling easily.

    At least everything is working now, but of course something had to break in the process!

  6. #6
    Newbie AnimeCommander's Avatar
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    Why would you disable "USB Legacy Support" rather than just 'boot from USB'? If your PC is having issues with checking for USB boot devices, telling it to not boot off USB would stop that and you'd still have POST USB support.

  7. #7
    Constant Bitrate utd09bry's Avatar
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    Quote Originally Posted by AnimeCommander View Post
    Why would you disable "USB Legacy Support" rather than just 'boot from USB'? If your PC is having issues with checking for USB boot devices, telling it to not boot off USB would stop that and you'd still have POST USB support.
    I already had USB boot disabled, but for whatever reason the system boots up a lot faster without legacy support enabled. Maybe the USB emulation is slow.. don't know. I will note that I have found that this alone does not solve my original problem... I've been trying all sorts of GPS locations, and any spot that gets too hot creates problems. I think it is just the GPS operating outside of its functional temperature range.

    I am in the process of testing it on my roof. It may not get as hot considering the ambient temp will actually be cooler than the car. It is sitting out there right now, so I'll see how it runs when I get off work. Will update later..


    UPDATE:

    Couple things learned:

    1) Mounting GPS on roof of car is night/day difference in signal strength and aquisition time. This is even compared to having it on the dash under the windshield only. It gets satellites (always 8-12) extremely quickly on a cold boot, and the signal strengths are very very high. Awesome!

    2) Today was a scorcher here in Houston. In direct sunlight, baking for 8 hours the GPS was warm and PC was bootable. This is compared to the burning-to-the-touch GPS when it was inside my car in direct sunlight. It's amazing what the high ambient temperature can do to it. It heats up THAT much more while inside the car. Now just to hope it truly lasts through weather :-p . I'll be popping it off and sticking it inside if any hurricanes are rolling through!!

  8. #8
    Newbie AnimeCommander's Avatar
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    Well I understand about the boot times with and without the legacy support on. I'm just trying to avoid having the GPS antenna externally mounted. I'll be putting mine in a custom enclosure with some extra air space, so I'm hoping that'll help.

  9. #9
    Constant Bitrate utd09bry's Avatar
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    Quote Originally Posted by AnimeCommander View Post
    Well I understand about the boot times with and without the legacy support on. I'm just trying to avoid having the GPS antenna externally mounted. I'll be putting mine in a custom enclosure with some extra air space, so I'm hoping that'll help.
    Anything that might shield the direct sunlight should be okay. In my case, the dash itself was quite hot (black plastic segment), and the GPS sitting on this combined with the 130F+ ambient temperature as well as direct sunlight all added up (as mentioned before, in excess of 160 or 170F).

    I would think if you can come up with some kind of plastic or wood container you might be able to get good results

  10. #10
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    I have a Holux Slimline powered through an external hub and have no such problems. Battery is cooked though. I live in Jordan and things can heat up here quite a bit!
    Glue of my velcro is melting on a regular basis!

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