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  • 12v to 19v and some other question

    hi guys
    I'm pretty new to all this car customizing stuff.
    A month ago I put in a active subwoofer and a radio.
    that went quite well,and was fun to do.

    Now I have an old laptop that has a busted keyboard and i was wondering how to install this in a car.

    I've nosed around the internet/forum but there is no real guide to this, and seeing as everylaptop is probably different i can assume why.

    anyways.

    my big question is: Is there a 12v to 9v adapter.
    I think its a bit lame to stick a sigaret-lighter converter that goes from 12v>230v>19v.

    I also wonder if it is possible to put in a secound battary,as a reserve one(still dont know why cars only have 1 battary), that loads when driving but only unloads into the laptop.

    and are there ways to unatach and extend the laptop screen(using the same powersource, ofcoarse) and attach it somewhere else (thinking of putting it on the viser) that way can use the laptop screen, and save me a screen-purchase and another powersource problem.

    I dont know if i'm looking at this the right way, but those seem to be the problems that come in mind.

  • #2
    Originally posted by jasonteunissen View Post
    my big question is: Is there a 12v to 9v adapter.
    Yes. Check the Carnetix power supplies in the store here.

    I think its a bit lame to stick a sigaret-lighter converter that goes from 12v>230v>19v.
    Inefficient, as well.

    I also wonder if it is possible to put in a secound battary,as a reserve one(still dont know why cars only have 1 battary), that loads when driving but only unloads into the laptop.
    You can, but it's really not worth the time, effort & expense, especially with a laptop that has its own battery.

    and are there ways to unatach and extend the laptop screen(using the same powersource, ofcoarse) and attach it somewhere else (thinking of putting it on the viser) that way can use the laptop screen, and save me a screen-purchase and another powersource problem.
    IT can be done, but again, it's far simpler to just use an external screen.


    Time to start perusing the FAQs. Link is in my signature.

    Welcome to our madness!
    Have you looked in the FAQ yet?
    How about the Wiki?



    Under normal circumstances, a signature would go here.

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    • #3
      thx for the quick reply, I;ll check your faq

      Comment


      • #4


        some stuff to add:

        there is a thread, think in the general section about wheather your carpc killed your battery.. so far, the only dead batteries reported were after over 10hours of usage..

        i don't think that a second battery is necessary, but that a opinion, and you know what they say about that..

        screens: extending it is a tricky deal-- most have done it to netbooks, so try to search for those..
        My OLD 2001 Mitsubishi Eclipse GT:
        "The Project That Never Ended, until it did"


        next project? subaru brz
        carpc undecided

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        • #5
          I'll see if i can find an sxtended notebook screen.
          the whole reason i wanted to do the laptop carpc is to save money, it doesnt have to be the most powerful carpc around, I just wanted a fun challange.
          And i think buying an extra screen will kut into my nonexisting budget.

          Comment


          • #6
            Consider a battery protector aka low voltage cut out (LVCO).
            The MW728 handles 10A (~$20).

            Quite a few of my posts provide various solutions (else suggestions) for latching relays with optional LVCO; increasing MW728 cut-out voltage (st'd is off @ 11.2V; on at 12.5V); additional batteries with "smart" isolators (usually a mere on-of relay).

            Comment


            • #7
              i'm new here but i'm guessing a "low voltage cut out (LVCO)" kuts the power suply if your battery is below a certain point.

              I'll also look into that

              Comment


              • #8
                Exactly.
                It can also be considered a HVTO - High-Volt Turn On because it turn on at 12.5V and above.

                If 11.2V off & 12.5V on are too high, it can be easily increased with diode(s) and a relay...
                Add a diode with (say) 0.3V to 0.7V "forward voltage drop" to its input. (Typical diodes like 1N400x (1N4001, 1N4004, 1N4007 etc) have a ~0.6V drop.)
                That drops the voltage by (eg) 0.6V hence tricking the LVCO (MW728) to turn off at 11.8V and back on at 13.2V (which requires the alternator to be charging).
                BUT - you then have the LVCO turn on a relay that power the load.
                The relay means (1) that you don't need a 10A or higher diode to carry the load current THROUGH the MW728, and (2) you can use a 15A, 30A, 200A etc relay for bigger loads.

                Other tricks include a push-button to bypass (short out) the diode so it initially turns on at 12.5V (for a normal full battery without engine running) but then cuts out at (11.2+.6=) 11.8V and does not turn on again until the battery exceeds 13.2V.
                But there are lots of possible variations to the above.
                And tricks to prevent the MW728 "cycling" due to battery variations. (I had a problem battery that dropped to 11.2V and then recovered to 12.5V - the MW728 was cycling on & off every 15 seconds!)

                Comment


                • #9
                  like i said i'm new to this stuff so trying to work out the problems as i go along.
                  but thx for the info i will keep it in mind.

                  I also found:
                  http://www.mp3car.com/vbulletin/lcd-...cable-faq.html

                  veryhandy seeing as that i would like to use my screen.

                  now all i have to do is find the 12v>19v adapter somewhere in my country or see if they deliver it to holland. (not a big fan of online shops)
                  and also what the price ranges are.

                  but seeing as we have the power,battary and screen problems "theoretecly solved" I will try and attempt to make this a reality.

                  and then i start can worrying about software.....

                  Comment


                  • #10
                    check the dc-dc power supplies first-- some have a low voltage cutoff adjustment-- these will shut off the pc more gracefully then other lvco's..
                    My OLD 2001 Mitsubishi Eclipse GT:
                    "The Project That Never Ended, until it did"


                    next project? subaru brz
                    carpc undecided

                    Comment


                    • #11
                      Originally posted by soundman98 View Post
                      check the dc-dc power supplies first-- some have a low voltage cutoff adjustment-- these will shut off the pc more gracefully then other lvco's..
                      so the powersupply to my laptop should include a voltage cutoff adjuster.
                      I will consider this while browsing for my power supply
                      thx

                      then all i need to do is find a way to extend my screen and I should be up and running

                      thx

                      Comment


                      • #12
                        I agree with soundman - there are some great dc-dc converters with low standby currents and the handshaking required for graceful shutdown - ie, UPS functionality - PSU (dc-dc conv) sends "battery low - shutdown imminent"; PC starts shutdown; PSU shuts down when load drops or after a pre-adjusted time delay (or when battery is too low - ie, it collapsed quicker than anticipated).

                        I have devised similar timed handshaking using the MW728 (it triggers a timer that hold power on), though just now I wondered if another great HVTO/LVCO kit can be internally tapped for handshakes. (The kit is the $22 Oatley Electronics (Australia) K227 - 12-24V Dual Battery Adapter For A Vehicle, but you need to solder & assemble and house it. But it has an adjustable voltage level & better delays than the MW728; uses a latching 80A relay; and only consumes 50uA else 500uA (0.5mA) with a LED. An has other potential mods given its circuit & operation description - not that I fully understood it!)

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