Page 2 of 2 FirstFirst 12
Results 11 to 17 of 17

Thread: Carputer question

  1. #11
    Newbie
    Join Date
    Mar 2010
    Posts
    12
    Because 130w has to be considerably higher than a stock stereo.. Granted, 12v @ 11a (132w) isn't all that much.. It's nice to know.

    The A/C has a clutch and is attached to the serp belt, in most vehicles. I think only hybrids really use a fully electric A/C? .. Wouldn't that be the reason for the MPG lost there?

  2. #12
    Newbie bad_luck's Avatar
    Join Date
    Jun 2009
    Location
    Heerlen, Netherlands
    Posts
    37
    Pfff... to be honest, now you're talking me under the table !
    (very bad english translation, just to say that now you're telling me more then i know about this ..) I only know the basics, apparently ... Maybe someone else can help you with this ?

  3. #13
    MySQL Error soundman98's Avatar
    Join Date
    Jan 2008
    Location
    on the border of northern IL/IN
    Posts
    5,820
    i think you are both starting to overthink this-- think of it this way-- a alternator is like pedaling a bicycle--you are always pedaling to keep going(ie; alt. is always creating voltage/current) but when you encounter a huge hill, you reallyneed to pedal to get up the hill(ie; alt works hard to overcome huge power draw).

    so the alt is always there producing energy, but only produces what is needed to a point.

    every electrical device you add to the car will increase fuel consumption slightly, but, realisticly, you probably won't notice it, and if you are that critical of your fuel economy(hypermiler?), you would have already taken out your door panels, and passenger seats to save gas.
    in this case, even a standard radio is not for you(extra wheight and something else to power),

  4. #14
    Newbie
    Join Date
    Mar 2010
    Posts
    12
    Sound.. The alt works harder, yes.. generates more heat, lowers life-span, etc...

    But, doesn't it always draw the same energy away from the wheel? The volt-regulator simply limits the amount of energy that goes to the bushings (iirc.. may be completely off here.), thus - less is created.

  5. #15
    Low Bitrate
    Join Date
    Feb 2010
    Location
    Kentucky
    Posts
    84
    The answers have mostly already been given throughout this thread but just to clarify a little bit...

    I ask, (not specifically that person, but this sparked my interest.) how do you power it? Most PC power supplies of course, take 120v... But possibly more significant, they're very large. What do you use?
    You can use either a DC/DC power supply like the M2 or M4 or others, or you can use a DC/AC inverter and a standard AC power supply but that will be less efficient and less convenient.

    So, the alternator gets that extra power by increasing tension on the belt, right?
    No, the belt tension does not change. The alternator supplies the current as demanded by the connected electronic devices and the magnetic torque increases as current increases, which is why more electronic devices can have a negative impact on fuel economy, though usually small.

    But now, i do know that when you, for example, turn on your airconditioning, your car DOES use more fuel ... Now how that is possible?
    The fuel economy lost from running the AC is due to the mechanical power required to run the compressor. When the AC is off, the compressor is disengaged from the engine drive, usually by a clutch.

    Like soundman98 said, unless you are a hypermiler, it is probably not worth worrying about the fuel economy impact of running a carpc. A small form factor computer should use well under 100W most of the time, and there are many, many people running 5-600W RMS audio systems off of stock alternators.

  6. #16
    Constant Bitrate Sleepyz0mby's Avatar
    Join Date
    Feb 2010
    Location
    PanamaCityBeach/NewOrleans
    Posts
    171
    look im really sorry to beat this to death but its (alternator) really misunderstood...

    1 hp = 745watts, watts = volts * amps, volts = 13.8

    1 hp = 13.8v at 53amps (not calculating inefficacy)

    so it can be safely assumed that 750 watts is going to about equivalent of sticking your hand out the window if not less

    moving on to the alternator. the alternator has in-side coil (inductor) and an out-side coil (stator). the regulator is exactly what it sounds like, it regulates volts to 13.8 (some times more or less). it does this by applying current to the inductor coil to create a magnetic field. that magnetic field causes the stator to generate three phases of ac voltage though diodes to make dc (13.8v). now amps come into play as the "how much 13.8v" needed, if you have an amplifier thats constantly pulling 750 watts it would require the regulator to redirect enough current though the inductor (more current = more heat, heat = bad) to create a magnetic field strong enough to maintain 13.8v.

    side notes - alternators/regulators have limits (commonly 120amps to 175), the max advertised output of alternators are made at or above driving rpms (>2000 rpms) not idle, alternators can drop a diode and "limp" with 2 phases unnoticed

    and thats the easiest way i know how to explain it...

  7. #17
    Low Bitrate
    Join Date
    Feb 2010
    Location
    Kentucky
    Posts
    84
    Quote Originally Posted by Sleepyz0mby View Post
    look im really sorry to beat this to death but its (alternator) really misunderstood...

    1 hp = 745watts, watts = volts * amps, volts = 13.8

    1 hp = 13.8v at 53amps (not calculating inefficacy)

    so it can be safely assumed that 750 watts is going to about equivalent of sticking your hand out the window if not less

    moving on to the alternator. the alternator has in-side coil (inductor) and an out-side coil (stator). the regulator is exactly what it sounds like, it regulates volts to 13.8 (some times more or less). it does this by applying current to the inductor coil to create a magnetic field. that magnetic field causes the stator to generate three phases of ac voltage though diodes to make dc (13.8v). now amps come into play as the "how much 13.8v" needed, if you have an amplifier thats constantly pulling 750 watts it would require the regulator to redirect enough current though the inductor (more current = more heat, heat = bad) to create a magnetic field strong enough to maintain 13.8v.

    side notes - alternators/regulators have limits (commonly 120amps to 175), the max advertised output of alternators are made at or above driving rpms (>2000 rpms) not idle, alternators can drop a diode and "limp" with 2 phases unnoticed

    and thats the easiest way i know how to explain it...
    Excellent explanation of how the alternator works! Thanks!

Page 2 of 2 FirstFirst 12

Similar Threads

  1. pioneer Avic F500BT - a $250 carputer ???
    By kafklatsch in forum General MP3Car Discussion
    Replies: 1
    Last Post: 11-09-2009, 04:25 AM
  2. Question about my new CarPuter
    By toddwess in forum General MP3Car Discussion
    Replies: 11
    Last Post: 04-02-2006, 04:33 PM
  3. Carputer Question
    By 93RPS13 in forum Newbie
    Replies: 24
    Last Post: 05-26-2005, 02:29 PM
  4. CarPuter & Bass Question
    By jforster in forum Newbie
    Replies: 5
    Last Post: 08-26-2004, 09:33 PM
  5. XBOX, Carputer, power Question! ELECTRIC GURUS HELP!
    By EggrollXpress61 in forum General Hardware Discussion
    Replies: 5
    Last Post: 08-21-2004, 12:15 AM

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
  •