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Carputer problem (Power?)

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  • Carputer problem (Power?)

    I had my carputer hooked up to a 12v source and it was working fine then I decided to add a battery based tank circuit. Now when I try to start it up the screen and computer both come up, but after about 5 seconds the screen turns blue and the no input message comes up. The power LED on the computer remains on but like I said before there is no video signal. I am guessing that it is a problem with the tank circuit since that is all I changed. Is there an easy way to fix this, or should I just go back to my old setup?

    -Swinson Terry

    Tank circuit:

  • #2
    you can borrow a power supply and try it, if have the same problem, maybe your screen borken.


    • #3
      Like I said before everything was working just fine before the upgrade so I dont think its the power supply or screen.


      • #4
        Must be the tank circuit then....

        Post a diagram with sizes/ratings etc if you want diagnosis.


        • #5


          • #6
            Diode voltage drops.
            Try shorting the upper diode as a test.

            (Diode isolation might be "simple", but it does suffer from voltage drops. Relays are still simple but avoid the drop.


            • #7
              When diagnosing a problem you always want to eliminate all non essential things first.

              If you remove the tank circuit, does the system operate as before?

              If so then it is defiantly the tank circuit. I agree with the above post, the upper diode may be dropping your voltage to low for your + PC Supply to operate correctly.

              Cheers and good luck!
              2003 HCH Work Log
              - Official OpenMobile Builder/Tester


              • #8
                Both diodes will....
                They aren't particularly low voltage types - Schottkys might be ok, but it indicates that only a low voltage drop (say 0.5V) is enough to prevent boot up - not that you would boot up on a tank circuit.

                Whether the booted system will operate reliably is a different issue, but that 0.8AH battery will both drop its voltage AND discharge very quickly - eg, fully charged at 1.6A load, it will immediately drop to under 12.0V (~11.8V) and be at 11.0V within 6 minutes (from Yuasa Specs) - so in that case, I think no (it will crash).