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Will this work - Laptop install

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  • Will this work - Laptop install

    Very new to this forum...I have been reading and searching, but I cannot find this answer explicitly

    I am in the midst of installing my very 1st car PC.

    Am using a laptop IBM X31 with Port Rep, remote Mod - plan to run this off an auto/air adapter - power consumption is 16v 4.5AMP, air adapter is 70W.

    I purchased a 7" touch screen off ebay - rated power is DC 11-13V, power consmption <9w. The unit has an inbuilt power regulator.

    My question is whether this is the right approach for hard wiring the power into the car:


  • #2
    yes it would be fine as long as ur power supply can supply the proper amount of current. but you may want to invest in a power supply to provide all your components with clean regulated power so you dont blow them from cranking and what not


    • #3
      Also I suggest that you do not use the cigarette lighter to wire that. I would run a seperate wire from the battery.

      Also if you are interested in automatic startup and shutdown integrating with the car going on and off, I suggest a DC-DC laptop power supply such as one from Carnetix (available in the mp3car store as well).
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      • #4
        So if I was to purchase the P1900 with the P5V, would the wiring diagram look something like this, or do I still need the power adapter for the laptop?

        I assume that this will mean I will need to fabricate the power wires from the P1900 to the laptop and screen, and from the P5V to the USB hub?

        Or are there other methods avaliable?

        I assume then if the P1900 is installed, I will have scope to install other car pc's in the future (i.e. Mac Mini's or P4 units) within power limitations?
        Attached Files


        • #5
          Don't worry, i've found the answer out over at the Carnetix support site.

          For those 98 viewers who are interested, the P1900 can't power this notebook due to voltage output being excessive, however Carnetix have plans to introduce the P2140 with a mod that will cover the 16v requirements of most IBM notebooks.
          So it looks like I will need to save some $$ for the new P2140 & P5V when they come out to complete my project.


          • #6
            you don't have to wait for anything to come out. your original idea was fine...

            power the laptop with an auto/air adapter. and power your monitor from the cig lighter socket (the built-in regulator is fine). I would run a new (fused) line to the battery to power the auto/air adapter. you can power the monitor from that too, but it only uses 9w so the cig lighter cicuit provides plenty of power for that.

            later on you can "upgrade" to that new carnetix model but it's not really necessary.

            good luck
            F150 Truckputer [1.0] (coming soon!)
            Fusion Carputer [2.0]
            Fusion Carputer [1.0]


            • #7
              Originally posted by colbyau View Post
              Don't worry, i've found the answer out over at the Carnetix support site.

              For those 98 viewers who are interested, the P1900 can't power this notebook due to voltage output being excessive, however Carnetix have plans to introduce the P2140 with a mod that will cover the 16v requirements of most IBM notebooks.
              So it looks like I will need to save some $$ for the new P2140 & P5V when they come out to complete my project.
              ive got a buncha extra voltage jumpers to change the primary out because i had to buy the whole pack. PM me if you'd like one.


              • #8
                Computergeek - thanks for the idea on the fused link (using a 1AMP fuse holder I assume?), but I'm not sure how I would stop the auto/air adapter from drawing power when I have the car switched off.

                Any suggestions on how I would wire up something that would turn on when i turn the ignition on? I was thinking perhaps a relay of some sort that activates when the key is set to acc?

                hari-bhari - i'll give the regulators a miss, but thank you too, i am happy to wait for the P2140 with the autosensing module.


                • #9
                  switching it on/off with the ignition is easy. you have the right idea already. a relay switched off the ACC wire. you can use the ACC wire from the fuse box, or splice into it behind your head unit

                  everything you already planned will work fine, my current system is setup almost exactly the same way. i have a Dell Inspiron 8000 (unmodded) plugged into a docking station (with the power button, remote switch) and a Lilliput EBY701. I use a cheap auto/air adapter ([email protected]) which is powered off my 4AWG amplifier power cable (with a relay hooked up to turn it on/off with the ignition). power for the monitor comes from the front cig lighter circuit (with another relay hooked up so it shuts off with the ignition). the auto/air adapter works good, and provides [surprisingly] stable voltage, but it got extremely hot in it's original plastic case (so hot it actually hurt to touch it until it cooled off), so i removed it from the plasstic case/shell and mounted it in an empty ATX PSU case and wired the 80mm fan to the 12v relay feed so it also turns on/off with the ignition.

                  I didn't bother with a startup/shutdown controller because I don't want my carPC on all the time. I just wired a remote power button up front. I just switch it on when I need it (I kept a head unit for short tripd and general audio control, so I wouldn't need to rely on the carPC for all audio).

                  good luck
                  F150 Truckputer [1.0] (coming soon!)
                  Fusion Carputer [2.0]
                  Fusion Carputer [1.0]


                  • #10
                    i can't for the life of me work out how to wire up the relay to power when the ACC is turned. Can someone please provide me with a diagram?


                    • #11
                      this is a bit of a hijack.. but im in the same boat, i need to power screen (8w built in regulator i guess cause it came with cig adapter), laptop (about 80w?, 19v 4.22A), and dvd drive (5v, 2A)...

                      1. which if these should go to the hidden cigarette plug for power, i can get dc-dc adapters for both the laptop and dvd drive, the screen already has one.

                      2. can they all go on a 3 cigarette adapter? the kind of splitter that makes 1 into 3?

                      3. should they have ac adapters, and i get the best inverter i can find and connect them to that?

                      4. i have no more head unit, the wiring harness is still in the dash though, could i tap into the former power wire of the headunit?

                      5. my old head unit had a "turn on by ACC" function, could i use that wire to send a power on signal like say through that one turn on module i see here

                      thanks for any help


                      • #12
                        You got what you need

                        I wired a separate fuse box for my IBM R51 in a docking station, monitor, and amplifier. I have never had power issues with my computer, nor had my car battery die from this installation. Nor a fire (keeping fingers crossed). I did not need all the fancy setup offered with a shutdown controller, as I wired a switch from my dash to the docking station.

                        1. Run a heavy gauge wire from your battery to the new fuse box. Make sure to place an inline fuse as close to the battery as possible. Remember that the fuse rating is related to the thickness of the wire and not the draw from the system. Too much current for a wire may cause it to melt and poof! your car may catch fire.

                        2. You can now individually fuse each component with the proper sized fuse for the wires to them. I just cut the lighter end off a 120W car adaptor and wired the power for the computer into one fuse slot, the amp into another, the screen into another, and a five volt USB adaptor with spliced USB cable into the correct jack for my soundcard and USB hub, which in turn powers the GPS, mouse, etc. I have never had any power issues.

                        3. The power to the fuse box can be switched on and off with a relay that is wired to the ignition. That way when the car is off, the power to everything is off, which is how I want it. For some reason, the GPS on the USB hub stays powered from the laptop battery, but in sleep mode, it drains so little, that it very, very, very slowly drains the laptop battery, but not the car battery, as the relay isolates the circuit.

                        4. Make sure that all your connections are good and solid. Soldered is better than crimped if possible. Also, to reduce any interference, it is a good idea to try to ground everything to the same location with as short a run as possible. The grounds should be equal gauge wire as the power wires. And make sure the ground is clean and solid to a large piece of the car, i.e. frame of well attached body member.


                        • #13
                          holy smokes this is exactly what i needed, thank you.

                          i was wonering, by cutting off the cig adapters, you now run the wires to a new fuse box? or the cars fuse box, or just another inline fuse

                          are there fuse boxes where you can attach the power and ground to, and then have a master ground wire go to bare metal, or do i have to split black and red and run all the blacks to the same spot.

                          i think i want to... attach my availabe cig plug to my monitor, which only has a cig adapter anyways and draws only 8 watts... attach my slot dvd (5v, 2A) to the former power wire of my head unit... and run just 1 new power wire (with inline fuse) from battery to the auto/air adaptor for my laptop... hows that?

                          my screen turns on and off by video signal, and the usb drive should power down when the computer hibernates, i would set hibernate to 1 min or the minimum.


                          • #14
                            Sounds like you got it


                            My PC (with all the attachments) and stereo amplifier are mounted in my trunk. I purchased another fuse box at an auto supply store and mounted it on the side wall of the trunk. I wired the input of this fuse box with a heavy gauge wire directly to the battery, with an inline fuse as close to the battery as possible, and ran it along the left side of my car, under the carpet and trim.

                            Remember that the fuse rating has nothing to do with the power draw on the circuit, but everything to do with the wire gauge. If you over fuse a wire, it has the potential to melt the insulation and cause a fire ().

                            I opted to ground each powered tem to the same location to reduce any ground loop interference and noise. You will want to use the same diameter wire for ground as for power and make sure the ground wire is as short as possible and well grounded, or you WILL have noise in your system.

                            For your monitor, you can keep the cig lighter plug it comes with and connect it to an add-on cig lighter receptacle (available at auto parts stores). If possible, wire this receptacle into a available fuse under the dash or the power line from your stereo. Note that the touch screen of your monitor will be connected to your system with a USB cable and this can be a source of ground loop noise. I used a high quality USB cable and did not have a problem. I also taped the the monitor plug into the lighter receptacle with electrical tape to keep it from disconnecting.

                            The DVD will not work attached to your head unit, as it takes 5v, and a car stereo line will put out anywhere from 8-9V at the low end, to spikes of over 15V when the alternator kicks on. That is, unless you want to fry your DVD. There are several threads on a separate 5V power source. I tapped into one of the lines on my air/auto adaptor and it provides 5V, so this is what I power my USB hub with. Depending on the power adapter, you may be able to purchase a splitter and have one provide 12V and the other 5V.

                            I also used an automotive relay that switches the power to the fusebox and therefore the computer and amplifier off when the car's ignition is off. This completely separates the computer and stereo stuff from the battery - no possibility for a dead car battery from the carputer circuit .

                            Good luck and if you still can't get it going, I will try to draw a circuit diagram.


                            • #15
                              ThefDog - you got a diagram of how you wired the relay?