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any 12V sources inside laptop?

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  • any 12V sources inside laptop?

    I'm thinking about hacking up my tablet PC to put in a cheap high-capacity 3.5" drive. The problem is getting 12V to it. The tablet PC takes 16V, but there has to be a 12V supply inside the case somewhere, right? Any ideas where to find it? it needs to be able to handle up to an amp of additional current.

    Also thinking about getting an external power supply, but I would like to have as many devices as possible isolated from the car power supply by the tablet PC's included car DC/DC adaptor and its battery (plus it's cheaper and more compact this way).

    One more thing, nothing tricky about getting laptop IDE to work with a desktop drive, right? I couldn't find any adapters, but I think simply putting gender-changers on the 2.5"-to-3.5" adapter (designed to allow use of notebook drives in desktops) should work.


  • #2

    I also faced this problem. I am building carputer based on mobo from laptop. And, there is absolutelly no 12 volts power supply in board. Forget about it, you should do it yourself.. I am using max1771 chip with n channel mosfet transistors to convert 5v->12v (still have some power from laptop dcdc becouse i do not have any lcd attached to it ) But, its kinda hard to spin up HD, i succeed to spin up very old hard drives with 0.4 amps on 12v rail... My currend HD (maxtor 80gb eats 0.7A) doesnt spin up. So, I go for powering hd directly from laptop battery (works just fine!!!! with battery and external power supply) I have stable 12.2 volts on output... But, I blown up 2 max1771 chips, so waiting for new samples from maxim. I am using mostly free samples from the net for this converter. As far as i will finish, i'll publish my schematics AND urls where to get free samples for it. And, nice thing, u will only need only 1 resistor, 4 capacitors and coil!!!

    my icq 6678667.


    • #3
      and, i would say, u will need 1.5-1.7 amps to spin up HD...


      • #4
        I am using an Epia PSU to power my dvd drive and peripherals separately from the laptop. You don't want to overload the laptop power supply.


        • #5
          Heh, those maxim guys are great! I'll be getting some samples from them too!
          I'll be drawing power from the 16V battery / P/S. With a 5400RPM drive, that should be enough.

          Thanks for the tip!


          • #6
            Originally posted by dimas
            Heh, those maxim guys are great! I'll be getting some samples from them too!
            I'll be drawing power from the 16V battery / P/S. With a 5400RPM drive, that should be enough.

            Thanks for the tip!
            I don't want to spoil the fun, but I believe I have read somewhere that the battery pack delivers 10,2 volts or something like that. Don't know why the 16 volt supply is needed, but then again, I am no electrician.

            In Holland you can get a 20gb laptop harddisk for about 100 euro's which should be about $85,-. I guess in the USA it would be even cheaper?

            Be carefull with (re)formatting, I really messed up trying to get a UK version of Win98 installed on it. Best is to make an image of the original disk, and restore the image on the new (larger) disk.

            Another option would be to search E-bay for a PCMCIA disk like:





            • #7
              Yeah I just checked and the battery indeed only provides 10.8V. The car DC/DC adaptor that was included with the tablet PC provides 16V though. That's where I'm planning to get the juice from.

              The only reason I'm doing this is that I have A LOT of music and a lot of audiobooks. Over 60GB worth, which means that to fit it all I'd need an 80GB drive. Notebook drives of that capacity aren't cheap - about $200. However, I could get a 120GB desktop drive for about $80. So 50% more capacity, at less than 50% of the price, and with better performance characteristics - all I gotta do is find a 12V supply.


              • #8
                2FastHook: Goeden avond

                2dimas: yes! i have the same!!! battery - 10.6 when charging it have 11 and it DOES spin up 5400 80gb maxtor )))

                Got 3 amp shottky today, waiting for maxim's magic chips to finish it!!!

                I think, i'll make also relay to power converter when HD gets +5 volts.

                And, i dont think laptop psu will be overpowred, becouse it needs to power cd (1.5 amp) and lcd screen and floppy, which is quite some amps to. I do not have any of these pieces in my set anymore (probably i'll keep cd, but it is quite useless becouse i'll put puter in the trunc.

                Btw, did u guys see any carputer setup in bmw????? Mine dash looks like a aircraft's one, and i probably will have a little space for small lcd only ;(((


                • #9
                  I think use an external HDD will solve the solution


                  • #10
                    Yeah! My set is working like a charm!!!! Just sitting now and listening musik in my living room! Soon post details and pictures. Still have to put all stuff in nice box ))))