Page 1 of 2 12 LastLast
Results 1 to 10 of 16

Thread: Exactly how much does this drain the battery?

  1. #1
    Low Bitrate
    Join Date
    Jul 2004
    Posts
    96

    Exactly how much does this drain the battery?

    I just picked up the new 2005 Scion tC and I was wanting to put a LCD screen in it, with dvd player, mp3 player, and whatever else I could throw in. Well I stumbled upon this and became very interested. I have been up all night reading about how to do it, and basically picked out everything I would need. (I am a very fast learner)

    But, I have 1 question. Exactly how much more power will this type of system drain for the battery? Will it run the battery down any faster then it would with just a regular dvd player head unit with lcd screen? I wouldn't have the system running without having the car running, since obviously that will drain the battery alot quicker.

    Cliff notes:
    How much more does this drain the car battery from a normal dvd/lcd system?

    Thanks,
    -- Coy

  2. #2
    Raw Wave Confused's Avatar
    Join Date
    Aug 2003
    Location
    Essex, England
    Posts
    2,224
    It all depends on a few factors.

    Firstly, what components you decide to use. If you use something like the VIA Epia range of boards, then they are designed for low power usage, so they won't consume as much juice as standard desktop components.

    The other thing that affects it is the power supply you use. The most efficient thing to use is a DC-DC power supply, such as an Opus, or if you have a case with the Morex 55W DC-DC PSU (which will be in most of the "Mini-ITX" cases you can buy) then you can use the Carnetix CNX-P1260, both of which will give you >90% efficiency. This means that of the power that comes from the battery, over 90% of it will be used in the computer, and less than 10% will be "wasted" in the conversion.

    Compare that however to the other option, which is an inverter and a standard PC power supply. Most inverters will be around 75% efficiency, and add to that the PC power supply will be at best 75% efficiency, so using this setup, you'll be pulling over 150% of the power you need to just run the system!

    So, best bet is a DC-DC power supply, and depending on what you use, depends on how long it will last. I would estimate (but it is only a complete guess) an Epia setup will probably pull about the 150-200% of the power that a basic, standalone DVD/LCD will do, because of the nature of running a PC

    However, if the engine will be running, then it doesn't really matter, as the alternater will be charging the battery all the time


    Garry
    Co-Developer of A.I.M.E.E
    www.aimee.cc

  3. #3
    Newbie bathbiggles's Avatar
    Join Date
    Jun 2004
    Location
    Marlow, England
    Posts
    13
    Maybe a stupid question here, but i thought if your engine was running, basic phyiscs suggests that an increase in power requirements from your car pc means that your engine uses more petrol turning the alternator over to generate more current, no? Would have thought most cars would be able to cope with 12V pc, considering some people power 700W microwaves of their engines

  4. #4
    Newbie bathbiggles's Avatar
    Join Date
    Jun 2004
    Location
    Marlow, England
    Posts
    13
    damn, you beat me to it lol

  5. #5
    Low Bitrate
    Join Date
    Jul 2004
    Posts
    96
    Perfect,

    I'm going to use a board in the range of the VIA Epia, 900 mhz, 20 gig hard drive (ill upgrade later), 128mb of ram, etc etc..... and then use the Opus DC - DC. Then use the MediaEngine for interface. Probably modify alittle bit more to fit my needs. And use the Lilliput screen.

    As soon as I get out of planning stage and purchasing, I'll start posting pics and descriptions.

    Should be pretty sweet, the tC already has a nice setup, this will make it perfect.

    Heres the dash, where the screen will go.



    Directly behind that large square silver peice in the center, it folds up and reveals the double din radio. I'll place the screen there. Computer in trunk or somewhere else.

  6. #6
    Raw Wave Confused's Avatar
    Join Date
    Aug 2003
    Location
    Essex, England
    Posts
    2,224
    From experience, I cannot recommend you get yourself a Lilliput screen.

    Get yourself a Xenarc screen, it definately worth the extra money.


    Garry
    Co-Developer of A.I.M.E.E
    www.aimee.cc

  7. #7
    Constant Bitrate StationRocket's Avatar
    Join Date
    Sep 2003
    Location
    Rochester, NY
    Posts
    199
    Quote Originally Posted by bathbiggles
    Maybe a stupid question here, but i thought if your engine was running, basic phyiscs suggests that an increase in power requirements from your car pc means that your engine uses more petrol turning the alternator over to generate more current, no? Would have thought most cars would be able to cope with 12V pc, considering some people power 700W microwaves of their engines

    Yes, conservation of energy holds true here as it does everywhere, nothing is free. But the good news is that the change will be slight enough that you likley won't notice it. Now if you had that microwave going 24/7 allong with a cranked 1500W stereo and full size refrigerator it may be more noticable. But i'm guessing those things arn't in your plans.

    PS: if you wanted to do a little expieiment you could track your gas milage for a week and then do the same the next week but drive with your headlights on the whole time. Your factroy low beams are likley about 40W each and the highs are likley 10-15W more so 2 lights on (high or low beams) would be roughly the power consumed by a system running on an opus 90W

    Have fun and good luck with your project.

  8. #8
    See me in my wet t-shirt. stevieg's Avatar
    Join Date
    Aug 2003
    Location
    Warwickshire, UK
    Posts
    1,887
    Quote Originally Posted by StationRocket
    Your factroy low beams are likley about 40W each and the highs are likley 10-15W more so 2 lights on (high or low beams) would be roughly the power consumed by a system running on an opus 90W
    Do not forget that if you are using an Opus 90W you might not actually be using 90W - that is it's maximum. I should be around 30W

    you might find this useful:

    http://www.mini-box.com/powersimulator.html
    Ford Focus MP3 : www.stevieg.org/carpc Blog Updated 29 January 2009!
    Car PC Status: Complete - Undergoing Software Redevelopment

  9. #9
    FLAC samc's Avatar
    Join Date
    Feb 2003
    Location
    Brooklyn, NY
    Posts
    944
    My system draws at most 10A (90w) but never 100%. How's that for efficiency? ANd that's with DVD drive, screen, computer all running.
    Mine needs to be updated.

  10. #10
    Low Bitrate NorthGaVigor's Avatar
    Join Date
    Apr 2004
    Location
    Tenneessee
    Posts
    99
    Quote Originally Posted by bathbiggles
    Maybe a stupid question here, but i thought if your engine was running, basic phyiscs suggests that an increase in power requirements from your car pc means that your engine uses more petrol turning the alternator over to generate more current, no? Would have thought most cars would be able to cope with 12V pc, considering some people power 700W microwaves of their engines
    Not true! The alternator produces the same amount of drag on the engine no matter how much current is required by electronics. It is electrical and not mechanical. There is no physical connection inside the alternator itself to produce electricity.

    The only thing that will happen if you go over the output of your alternator/battery combo is you'll lose power or fry your alternator because it will try to produce more current when it can't.

    Air conditioning, power steering pumps are both mechanical and use more gas. Alternators do not!
    www.natchezss.com

    God Bless America and Our President!

Page 1 of 2 12 LastLast

Similar Threads

  1. Can I put an extra battery in my Chevy?
    By Mastiff in forum Power Supplies
    Replies: 14
    Last Post: 11-04-2008, 11:45 AM
  2. MPJA - MECI ASTEC DC-DC Converter
    By Luc in forum General Hardware Discussion
    Replies: 39
    Last Post: 11-22-2004, 09:31 PM
  3. Power drain on battery...
    By Ormo in forum Power Supplies
    Replies: 3
    Last Post: 06-23-2004, 12:40 AM
  4. S1 Standby Power Consumption Drain Battery?
    By Grayscale in forum General Hardware Discussion
    Replies: 6
    Last Post: 06-16-2004, 02:30 PM
  5. Replies: 1
    Last Post: 02-06-2004, 04:44 PM

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
  •