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  • Always-on car pc?

    I'm planning out a car pc build, and I want to something a bit different than most of the people on the forum...

    I'd like to run the car PC to be always on, even when the ignition is off. I haven't seen anyone do this, so I am curious as to why not? I think the big technical reason that people aren't doing it is because of the power drain - if your PC takes up 15 watts at idle, then running for one day takes 15*24=360 watt hours, which is 30 amp hours on a 12v battery - or about the total energy capacity of a small car battery. Now of course, I don't want my PC to just sit there and idle, I'd like it to run a few web cameras, and save the video off to an SSD. I am guessing my power draw will be around 25 watts while the car is off. I won't need GPS when the car is off, won't need to run the stereo, won't need to run the screen, won't need wifi, etc. All that would be running would be an accelerometer, maybe some parking sensors, and the web cameras. 25 watts is just a wild *** guess, by the way.

    I'd like to rig it up to GPS (or just a manual switch!) so that when I turn the car off when it is in the garage it will fully power down, so my running time while the car is off will be about 12 hours (a typical day at work) - maybe stretching up to 16 hours on occasion. 25*16 = 400wH / [email protected], so I think a 50 amp hour deep cycle battery should do the trick, and then plug in the car every night to top it off.

    Has anyone done anything like this? Any tips? Any 'gotchas' that I should consider? Thanks!

    -Bill

  • #2
    Have you looked in the FAQ yet?
    How about the Wiki?



    Under normal circumstances, a signature would go here.

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    • #3
      Haha Darque

      CyberBill, What your asking, you either will have to pay a lot of money for, or write a lot of software to do yourself.

      http://store.mp3car.com/Ivtek_SSD_Hi..._p/com-162.htm

      That seems like with a little modification and an extra small PC, it will do what you need. The only caveat would be that you might need a solar cell to keep your battery topped off while the computer is running, just to offset the constant power usage. Then you have the PC pay attention to your location when you turn off the car, and if it's at home, you turn off the camera power. If it's not at home, you keep the camera power on. Once again, it's likely going to require some programming, but a manual switch would be much easier.
      "stop with the REINSTALLS, what do you think we got some lame-o installer!!!" - mitchjs
      RevFE
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      • #4
        Originally posted by malcom2073 View Post
        CyberBill, What your asking, you either will have to pay a lot of money for, or write a lot of software to do yourself.
        Luckily, I'm a computer programmer, so that covers both bases! haha

        The Rupel iVox is a great recommendation - it is on my list for sure. Although, I have some concerns with that device because it's so new. For example, I'm not sure how the quality of recording both cameras at the same time holds up, also I don't know how many MB per minute is required for recording, so I don't know how much time 16GB will buy me. I'm not sure if I can manually force it to start recording, or if the accelerometer is the only way to trigger it. Yada yada yada, you get the idea. It also limits me to only recording two cameras and doesn't give me the capability to automatically upload the videos or to notify me with a text message that the accelerometer triggered an event. But still, it's on the short list! Honestly, if I got it, I wouldn't even need the car pc, so it would save me a crap load of money.

        The solar panel recommendation is something I've considered, too. I'm putting this in a Honda CR-Z, and it has a big window in the back. I've got about 85 tabbed 3x6 solar cells left over from a project I was working on, and that would fill up the area pretty well and give me probably around 100 watts, more than enough power to keep the battery topped off.

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        • #5
          CR-Z is a hybrid right? Wonder if you could tap into the battery for the electric assist side...
          Tidder

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          • #6
            Originally posted by CyberBill View Post
            Luckily, I'm a computer programmer, so that covers both bases! haha

            The Rupel iVox is a great recommendation - it is on my list for sure. Although, I have some concerns with that device because it's so new. For example, I'm not sure how the quality of recording both cameras at the same time holds up, also I don't know how many MB per minute is required for recording, so I don't know how much time 16GB will buy me. I'm not sure if I can manually force it to start recording, or if the accelerometer is the only way to trigger it. Yada yada yada, you get the idea. It also limits me to only recording two cameras and doesn't give me the capability to automatically upload the videos or to notify me with a text message that the accelerometer triggered an event. But still, it's on the short list! Honestly, if I got it, I wouldn't even need the car pc, so it would save me a crap load of money.

            The solar panel recommendation is something I've considered, too. I'm putting this in a Honda CR-Z, and it has a big window in the back. I've got about 85 tabbed 3x6 solar cells left over from a project I was working on, and that would fill up the area pretty well and give me probably around 100 watts, more than enough power to keep the battery topped off.

            100W is a bit overkill, but it dosen't hurt to overkill :P. Those are the half volt 3x6's? 42 of them would give you a 27W 16V panel, plenty enough to keep your batteries topped off on that thing I'm sure. The only question would be, on a really cloudy day, would your battery be big enough.

            On a side note, I'd hate to even think about soldering together 85 of those panels :/. Makes my hands cramp just thinking about it.
            "stop with the REINSTALLS, what do you think we got some lame-o installer!!!" - mitchjs
            RevFE
            My Shop

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            • #7
              Originally posted by Tidder View Post
              CR-Z is a hybrid right? Wonder if you could tap into the battery for the electric assist side...
              Yep, it is a "sport hybrid". It has a 100.8v, 5.75aH, ~575wH NiMH battery pack, and then it has a very small 12v starter battery. All things considered, 575wH is tiny. A Nissan Leaf has a 24kWh pack (50x as much capacity), a Volt has a 16kWh pack (32x), even a Prius has a 1.8kWh pack (3x).

              That said, I would never attempt to touch the hybrid pack! Too much voltage, too many amps, too dangerous for me. Besides, I can toss in a deep cycle 12v AGM battery with the same (or more) capacity for like $150, and then not have to worry about blowing out the super expensive hybrid pack.

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              • #8
                Originally posted by malcom2073 View Post
                100W is a bit overkill, but it dosen't hurt to overkill :P. Those are the half volt 3x6's? 42 of them would give you a 27W 16V panel, plenty enough to keep your batteries topped off on that thing I'm sure. The only question would be, on a really cloudy day, would your battery be big enough.
                They are around 1.8 watts each - I'm spacing on what the voltage and amps are. All 85 would give me 150 watts, but having it not at the optimal angle, and behind a tinted window... probably won't even hit 100. But you're right - its better to go overkill.

                Originally posted by malcom2073 View Post
                On a side note, I'd hate to even think about soldering together 85 of those panels :/. Makes my hands cramp just thinking about it.
                Yep! Even the pretabbed ones are a pain in the ***. Oh well, better than SMD work.

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                • #9
                  Sounds like an interesting project.
                  I know a few users have done always on computers for things like remote start and other simple taks like that. For these they used things like beagle boards that draw far far lower amounts when on. Maybe you could look at how well they could store video etc?

                  If you are running off a dual battery system I can't see too many issues, make sure it isolates so it doesn't flatten the starter.. Have it setup to shutdown if the battery gets too low (what happens if you have to leave the car overnight.. or want to power IR leds for night vision)

                  As long as you are happy with it only being always on in "typical" situations that you planned for and happy for it to shutdown in extreme cases then what you have planned should be fine. If you truly want it to be always on then I think you need to look for a much lower power consumption than normal. Even an atom or an AMD E350 will suck down the juice quite quickly.

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                  • #10
                    Originally posted by CyberBill View Post
                    Yep! Even the pretabbed ones are a pain in the ***. Oh well, better than SMD work.
                    really? just finished building a led panel consisting of plcc2 smd led's--31 of them.. i didn't think it was that bad...
                    My OLD 2001 Mitsubishi Eclipse GT:
                    "The Project That Never Ended, until it did"


                    next project? subaru brz
                    carpc undecided

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                    • #11
                      Originally posted by soundman98 View Post
                      really? just finished building a led panel consisting of plcc2 smd led's--31 of them.. i didn't think it was that bad...
                      Those probably aren't that bad because they are pretty large for SMD parts (3.5mm x 2.8mm, looks like), and they only have two junctions on opposite ends. Try a typical 1/4 watt SMD resistor, at 1.6mm x 0.8mm! Or a package device, like an Atmel microcontroller, with like 40 pins on it. Yuck. The pins are so close together that the solder just blobs up all over everything. Of course, this is a different problem than solar cells. With solar cells, the pads just don't hold very well, and the things are incredibly fragile and if you put pressure on them they just shatter. Doing a string of 10 or 15 of them... huge pain.

                      I used to make CCD cameras for astrophotography - got really old really fast, let me tell ya. :P Switched to a Canon DSLR - much less soldering, much easier!

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                      • #12
                        Originally posted by stretch4x4 View Post
                        ...beagle boards... Maybe you could look at how well they could store video etc?
                        Will do!! It looks like they support webcams, so that sounds pretty promising. I think I might also check out some IP network cameras. I figure they are probably doing much more processing in the camera than a webcam, and it might require less processing power in the PC.

                        Originally posted by stretch4x4 View Post
                        If you are running off a dual battery system I can't see too many issues, make sure it isolates so it doesn't flatten the starter.. Have it setup to shutdown if the battery gets too low
                        Absolutely, good call.

                        Originally posted by stretch4x4 View Post
                        If you truly want it to be always on then I think you need to look for a much lower power consumption than normal. Even an atom or an AMD E350 will suck down the juice quite quickly.
                        I agree. This is going to have to be a trial and error kind of thing. I don't know if an Atom will handle 4 webcam streams at once. I penciled in an Intel i3-2120T (2.6Ghz, 35W max), it is rated at about 4x or 5x faster than the fastest Atom, so it is overkill... so maybe in the next year we will see some faster Atom processors. I think using an Atom over the i3 would probably save me 5-10 watts, which is huge under the circumstances.

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                        • #13
                          get one of these to get the power u need
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                          CarPc
                          Project "Driver"

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                          Parts Collected [98.5%]

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                          Total Completion Level [96.9 %]

                          http://www.mp3car.com/vbulletin/work...ct-driver.html

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                          • #14
                            do you have a store link?
                            My OLD 2001 Mitsubishi Eclipse GT:
                            "The Project That Never Ended, until it did"


                            next project? subaru brz
                            carpc undecided

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                            • #15
                              When you need uninterrupted device operation, you should be looking at a UPS, uninterruptible power supply.
                              You can buy a "Mini-Box picoUPS-120 ATX DC micro UPS system / battery backup system for 12V automotive enviroments." at MP3Car for
                              $34.95 , but low voltage battery cut-off not provided by this module.
                              For low voltage battery cut-off , you can buy a "12 volt power supply and DC UPS for use in cars with 10A pass through"
                              from powerstream.com for $82.00
                              As for the battery, http://www.odysseybatteries.com/acce.../hd680_545.htm for a Aluminum battery holder,$25.00 or $25.95
                              PC680 20 hour capacity 16ah $145.39 or PC545 20 hour capacity 13ah $137.31. You can also use a plastic battery case and PC 1230 20 hour capacity 55ah $281.57.
                              You can create an app for your front end, Centrafuse, RideRunner etc. to shut down all unnecessary programs and devices except for what is required when the car is in monitoring mode.

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