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Car Computer Project need info on dc to dc ATX Power Supply

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September 14, 2006 9:00:52 PM

I'm in the planning stages of building a car computer for my :oops:  2006 Town and Country.

I have a T42 laptop with Streets and Trips 2006 with usb GPS that works GREAT! Turn by turn directions are excellent.

Well, this got me thinking about buying a dedicated GPS for my vehicle, but the prices are IMO, CRAZY!!! So I started putting together a list for my first car computer project

Here's what I want:

1. Gotta have Winxp for Streets and Trips with USB GPS.
2. GeForce 7 series gaming card, preferably with no fan (power and noise concerns)
3. Ability to play DVDs
4. MP3/WMA/ETC playback
5. Somehow link into factory sound (USB FM Transmitter?)
6. Use DC to DC Power (Rather than invert dc to ac just to go back to dc)
7. Be able to run with 300 Watts or less
8. Touch screen would be nice
9. Wireless Keyboard and Track Mouse
10. Possible Wireless adapter (war driving anyone?)

all this has to cost less than a Garmin Streetpilot 7500 Automotive GPS ($1,289.00)

Here's what I came up with so far:


Lilliput 7" Touch Screen XGA TFT Car Monitor VGA PC $245.00 (Seems to be De facto Car Monitor)

GIGABYTE GV-NX76G256D-RH Geforce 7600GS 256MB $103.12

ECS C51G-M754 Socket 754 Micro ATX AMD Motherboard $51.12

AMD Athlon 64 3000+ 939 Processor $64.99

I found a few ATX dc to dc power supplies, but know very little about electricity/voltage/amp/watts/etc. There are 3 models of the 300 Watt ATX supply I'm looking at. Here they are:

ATX Outputs - Enclosed DC-DC, 5.91" W x 5.52" L x 3.40" H

Watts Model Input (VDC) Output (VDC) PFC Specification

300W MPD-830C 19-32 3.3V/5V/-5V/12V/-12V/+5Vsb No
300W MPD-830V 40-72 3.3V/5V/-5V/12V/-12V/+5Vsb No
300W MPD-830R 72-136 3.3V/5V/-5V/12V/-12V/+5Vsb No

My question :?: is, what is the difference between Input (VDC) 8O ? My car battery is 600 amps and I have a high output altenator (what ever that means) because I have a tow package with my town and country.

I plan on running power directly to the battery and using an inline fuse.

Anyone familiar with dc power? Can you tell me what power supply to get?

I have not decided on a case, but it will be micro ATX and will only need room for a DVD and internal 3.5 (considering a 2.5 for durability) hard drive.

The only thing I'm worried about is this power issue, OH.. whoops. Here is the link to the power supplies I'm talking about.

http://www.mgpowerusa.com/product/dcdir.htm#enclosed
September 15, 2006 2:04:38 AM

Well.. you are going to have a hard time fitting that 939 procesor on a socket 754 board. Around 200 pins short ;) .

The only Geforce card with no fans that I have seen are 6xxx cards. But for your uses at 6800 would do jsut fine. Its not like you are gaming on it. Plus the lower power requirements will help you.
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September 15, 2006 2:19:55 PM

Quote:
:D  LOL! :D  Put the list together too quick! Thanks for pointing that out!

After a little more research on video cards it looks like this one is the best bang for your buck and has passive cooling!

http://www.newegg.com/Product/Product.asp?Item=N82E1681...


Nice, but will it run on a 300W PSU, and will it fit in a mATX case?
September 15, 2006 2:46:13 PM

Quote:

I found a few ATX dc to dc power supplies, but know very little about electricity/voltage/amp/watts/etc. There are 3 models of the 300 Watt ATX supply I'm looking at. Here they are:

ATX Outputs - Enclosed DC-DC, 5.91" W x 5.52" L x 3.40" H

Watts Model Input (VDC) Output (VDC) PFC Specification

300W MPD-830C 19-32 3.3V/5V/-5V/12V/-12V/+5Vsb No
300W MPD-830V 40-72 3.3V/5V/-5V/12V/-12V/+5Vsb No
300W MPD-830R 72-136 3.3V/5V/-5V/12V/-12V/+5Vsb No

My question :?: is, what is the difference between Input (VDC) 8O ? My car battery is 600 amps and I have a high output altenator (what ever that means) because I have a tow package with my town and country.


Your car battery only outputs approximately 13.8 volts DC (VDC). So none of those power supplies are going to work. Also, if you pull the maximum 300W from a power supply at 13.8 VDC, you are going to pull roughly 22 amps (Power (in watts) = Amps x Volts).

I assume your van has approximately a 100-150 amp alternator so I would think you would have room for this, if you can find the right power supply.
a b B Homebuilt system
September 15, 2006 3:27:37 PM

One note of caution:
The battery in your car is a starting battery. It is designed for a lifetime of many shallow discharges followed by recharges. If you deep-cycle it, however, you will kill it in a matter of months or weeks.
If you plan to run this rig for extended periods without the engine running, you would do well to look at a separate deep-cycle battery, typically a lead-acid "AGM" type. They are designed to be discharged typically 60-80% between charges. Do not just replace your van's battery with one, however, as they have lower peak output which may not be enough for starting, especially in winter.
September 15, 2006 3:31:01 PM

Is it possible to add a second battery?

Or should I scrap this and go for the Power inverter?

Thanks so much for your help! :D 
September 15, 2006 3:33:08 PM

I only plan on running the computer when the engine is running.
September 15, 2006 3:42:06 PM

I've spent days looking at itx products. I have the room for a MicroATX case, so I'd like to try and get a good gaming machine in there.

We take long trips with a small pop up camper so it would be nice to have a decent gaming machine, along with GPS/MP3 etc.
September 15, 2006 4:13:48 PM

There are a few Video cards with out fans. I have a ASUS 7600 G somthing and it runs Great. Also you can get a CPU and MB for $99.00 on New EGG it is a socket 754 but if you are on a budget well that works.
a b B Homebuilt system
September 15, 2006 4:23:50 PM

It is hideously inefficient, but you'll get very clean power charging a deep-cycle battery with a generator, then running an inverter off it.
I paid less than $1K for a Dell 1505 with the ATi 1300x GPU. It runs Guild Wars quite well, and the is probably the most demanding game I play regularly that I wouldn't want to give up.
Depending on where you go and how green you want to be, you can add a solar panel to this setup to charge the battery during the day. Plans are available online.
September 15, 2006 4:50:54 PM

This is probably your best option for putting a computer in a car, this same place also has dc-dc atx power supplies upto 200W but without the extra car features. If you look at getting low power components like mobile cpus and the like you could get a decent gaming system that would work.

Edit: They also have touch screens.
!