Step down Voltage

Discussion in 'General Hardware' started by celticfan11, Jan 3, 2007.

  1. celticfan11

    celticfan11 Moderator

    Messages:
    744
    Location:
    Vernon, CT
    So I am not sure if this belongs here or not, but here goes.

    I need a 5V DC output in my car. I only have 12V DC in my car. How do i go about stepping it down from 12 to 5? Radio shack had no clue, go figure.

    Thanks in advance.
     
  2. Techno Child

    Techno Child web{designer} Folding Team

    Messages:
    871
    Location:
    Myrtle Beach
    Get a USB adapter that plugs into your power port/cig lighter in your car. These are usually used to charge cellphones/ipods and are available just about anywhere like radioshack/circuit city/bestbuy etc... Cut a usb cable that fits the usb output on the unit, and strip the wires back exposing the red and black wires. These will give you 5vDC.

    -tc
     
  3. celticfan11

    celticfan11 Moderator

    Messages:
    744
    Location:
    Vernon, CT
    ohh i forgot to add, the reason i am steping the voltage down is so i can hardwire it into the car so my cigarette lighter is no longer being taken up. And i dont want wires all over my car.
     
  4. Techno Child

    Techno Child web{designer} Folding Team

    Messages:
    871
    Location:
    Myrtle Beach
    So... Open up the casing on the usb adapter and take the power inverter out, mount it in a fancy project enclosure from radioshack and hardwire it from the trunk... You probably aren't going to find a unit that converts 12v to 5v without it plugging into your cig lighter.

    Good Luck
     
  5. Admiral Michael

    Admiral Michael Michaelsoft Systems CEO Folding Team

    What are you looking at powering? Cause power requirements are a factor when determining what to use when converting.

    From there own site:
    http://www.radioshack.com/sm-5v-fixed-voltage-regulator-7805--pi-2062599.html

    This solution only allows 1A of current but will most likely require a heat sink at that current usage.

    I've used something similar to convert a 12VDC wallwart to 5VDC to hardwire my garage door key entry.
     
  6. celticfan11

    celticfan11 Moderator

    Messages:
    744
    Location:
    Vernon, CT

    i am goign to be powering my sirius radio. It requires 5V not sure on the Amps.
     
  7. Admiral Michael

    Admiral Michael Michaelsoft Systems CEO Folding Team

    I don't see that taking too much current, you could always do what TC said, just mod a car adapter for the device to make it a permanent install.
     
  8. LeeJend

    LeeJend Moderator

    Messages:
    5,291
    Location:
    Fort Worth, TX
    Until you know how much current the radio takes you are wasting your time.
    Find out.

    USB adapters are ony rated to supply 0.5A so that's 2.5W to run a satellite
    radio. That's not much.

    As for mounting. Just get a new cigarette lighter socket from an auto parts store and wire it in under a seat or behind the dash and plug an off the shelf converter into the new socket.

    http://www.pinecomputer.com/restcarvoco.html 1 A

    http://www.pinecomputer.com/restcarvoco.html 0.4A

    http://www.powerstream.com/dc6.htm 2-3A