Page 2 of 2 FirstFirst 12
Results 11 to 18 of 18

Thread: Power Supply

  1. #11
    sj
    sj is offline
    Newbie
    Join Date
    Sep 1999
    Location
    irving
    Posts
    22
    Using standard $60 DC/DC AT style power suply is my way to go. I have never need to run my car pc elsewhere, i just take my HD from car and plug it with same removable IDE bracket to my home pc ( to load new data etc ).
    But yes, if you are running something else in car which requires AC then i understand or you have plenty of space.
    And yes inverters are also cheaper way to go but not so much, i did not had power suply so ac/ac suply + inverter is not so much less than dc/dc @ $60.
    sj

  2. #12
    Newbie
    Join Date
    Sep 1999
    Location
    Norman, OK, USA
    Posts
    48
    It looks like you forgot that my problem is that I ave an ATX board :O). I am still looking for an affordable DC-DC converter.

  3. #13
    Variable Bitrate
    Join Date
    Aug 1999
    Location
    Yorba Linda, CA
    Posts
    323
    Sorry, a DC-AC inverter won't work for me when my entire power supply can only be 2"x6" and 1/2" thick !

    I have designed an ATX DC/DC switching power supply because of my space constraints and also because:

    - DC/DC is cleaner: All subsystems in my DC/DC supply run above the range of human hearing: at least 100kHz, so 60Hz noise is not introduced into my audio system. Car audio equipment, unlike home stereo equipment, is not designed to deal with the 60Hz hum present in AC power lines. This is part of why people using inverters in their car have so many problems with hum and buzzing. Using an inverter is even worse since the output is a "psuedo-sine" wave with spurious frequencies and lots of noise.

    - DC/DC is more efficient. With an inverter the draw is 5.5A from 12V, but with a DC/DC converter my calculations show it will be around 2 or 3A instead.

    - DC/DC doesn't suffer from the voltage variance in a vehicle. I used to use an inverter, but the computer would reboot if I tried to start the car with it running. My DC-DC supply can operate from as little as 7V, so this won't be a problem anymore.

    Since my DC/DC supply is ATX 2.0 compliant, it will handle auto shutdown and everything itself.

    BTW: -12V is sometimes needed by (S)VGA video cards to generate video signals. Some video cards won't generate a signal without this -12V.

    Also, I do not advise passing the 12V from the car to your motherboard and drives. The voltage from the car can vary from 8 to 16 volts DC and I have heard reports of people having their hard drives spin down when the engine is off.


    --Jason
    Johnson Interface Solutions
    http://jump.to/m2pc
    Jason Johnson
    Yorba Linda, California
    http://www.m2pc.com

    MPC Phase IV - *** PENDING ***

  4. #14
    Newbie
    Join Date
    Aug 1999
    Location
    Chihuahua
    Posts
    54
    Jason Im wonder if you could put a site or send information to how to build a power supply to an atx board , thank you.

  5. #15
    Newbie
    Join Date
    Sep 1999
    Location
    Chicagoland, Illinois
    Posts
    14
    Jason, I was going to purchase a DC-DC converter from Arise Industrial Power Supplies for about 80 bux. Do you think there will be problems going this way? Are you going to sell power supplies like you are talking about building? The power supply from Arise Industrial Power is only going to be an AT power supply, but I figured I'd just shut the power off in Windows (as I haven't had a problem with it yet).

    sj - Where did you find the DC/DC power supplpy for 60 bux?

  6. #16
    Variable Bitrate
    Join Date
    Aug 1999
    Location
    Yorba Linda, CA
    Posts
    323
    My PSU will be an ATX style but will work with an AT board as well (you'll need a different cable for the motherboard). For auto shutdown with my supply when used with an AT board, you will need to connect a wire to one of the pins on the parallel or serial port (Most of the PowerChute drivers people use for shutting down AT systems toggle a line on the serial port).

    I plan on selling it for around $75.00, but the design and prototype are still being refined. The entire supply will measure 5"x2"x1.5" since this is my space requirement. Size won't be a problem for heat or make it more expensive than a full-sized supply. Plus it will be easier to mount

    If I can cram in the circuitry, I will also offer a model that will have an onboard 8-channel ADC for monitoring external analog sensors such as the temperature and voltage of audio amplifiers or engine monitoring. This model will have an RS-232 port on it which you can connect right to the
    motherboard or to a DB-9 serial connector.

    If you need a PSU now (mine won't be available for another month or so), I would try the $60 one sj mentioned. I haven't seen or tried it, but it sounds like it works fine.


    Check my car PC site at http://jump.to/m2pc in a few days for more info.


    --Jason

    Johnson Interface Solutions
    http://jump.to/m2pc
    Jason Johnson
    Yorba Linda, California
    http://www.m2pc.com

    MPC Phase IV - *** PENDING ***

  7. #17
    Newbie
    Join Date
    Sep 1999
    Location
    Norman, OK, USA
    Posts
    48
    Jason, when do you think you'll be able to sell it?
    SJ, could you give me the address of the web page where you found that power supply?
    Thanks.

    Bachir

  8. #18
    sj
    sj is offline
    Newbie
    Join Date
    Sep 1999
    Location
    irving
    Posts
    22
    I check address for my supply.
    Btw here is address for do-it-yourself-suply:

    http://www.geocities.com/SiliconValley/Circuit/1044/CPS.html

    sj

Page 2 of 2 FirstFirst 12

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •