MSI Wind and DC->AC Power Inverter

DarkStar02 · 07-30-2009, 01:21 AM

I have a Jeep Wrangler right now which isn't the best platform for a carPC, but I'm going to be selling it soon and getting a GS300 (a little more suitable). My family owns a car audio shop so I can get double DIN head units for relatively cheap already, but ever since my bout with the semi-successful carputer I put in my old Ranger I've been wanting to try again. My goal is to make this cost effective, considering I could just buy a nav unit from our store.

This is my idea for now, but I still need to figure out how to make the computer start when I turn on the car.

DC to AC power converter 300w -$40
MSI wind net top - $150
80gb laptop HD - $40
2 gb 200pin ram - $25
D-Link bluetooth adapter - $25
USB GPS adapter - $40
7" touchscreen - $200
==============
Total: $520

DarquePervert · 07-30-2009, 06:21 AM

Take the DC-AC inverter out of the loop and use a Carnetix.
It has a built-in startup/shutdown controller to control the PC with the ignition.
That and you don't have the headaches associated with an inverter.

DarkStar02 · 07-30-2009, 12:12 PM

What headaches are associated with power inverters? I just found the XoByte MiniSpark and was going to get one of those for powering on and off via Wake on Lan.

DarquePervert · 07-30-2009, 12:18 PM

Inverters are bulky.
Inverters generate more heat than is necessary.
Inverters are inefficient.
Inverters (especailly budget models) are more likely to introduce EMI into your system, resulting in "noise".

A PC's components (CPU, HDD, optical drive, USB devices, etc.) run on DC power
The power supply of a PC converts AC from the house into DC for the PC.
An inverter takes the vehicle's DC and converts it to AC to power the PC, which is then converted back to DC by the PSU.

A DC-DC PSU takes DC from the car's electrical system and converts/splits to the voltages required by the PC, all regulated and safe.
And far more efficient.

soundman98 · 07-30-2009, 01:03 PM

you will be very hard pressed to get a computer to be close to the price of a dd nav unit, and if the cost savings is one of the major reasons to go for a car compuer, i would say to go with the nav unit.

I have seen enough posts from people that have tried to build a brand new computer for less cost than a nav unit(it is more feasable if you are using spare computer parts you already have)-- it ususally ends up being double the cost, and you pulling hair over the whole thing- cause cheap electronics stop working quicker, and you will forget about all the little parts that add up quickly. i estimate that my build, done relatively cheap, was around $1500-2000, and that is around retail for most nav units...

but, my carputer will do things that no navigation head unit in the world, in any price range, is fully capable of (name one headunit with internet access built in)-- that is why i built mine.

DarkStar02 · 07-30-2009, 01:37 PM

Quote: Originally Posted by DarquePervert

Inverters are bulky.
Inverters generate more heat than is necessary.
Inverters are inefficient.
Inverters (especailly budget models) are more likely to introduce EMI into your system, resulting in "noise".

A PC's components (CPU, HDD, optical drive, USB devices, etc.) run on DC power
The power supply of a PC converts AC from the house into DC for the PC.
An inverter takes the vehicle's DC and converts it to AC to power the PC, which is then converted back to DC by the PSU.

A DC-DC PSU takes DC from the car's electrical system and converts/splits to the voltages required by the PC, all regulated and safe.
And far more efficient.

I tried using a carnetix P1900 in my last build and it was one of the main reasons I gave up on the system, lol. The MSI Wind comes with a case, a mini ITX board, a PSU, and a CPU all built in which is why I chose it, how would I go about using the DC-DC PSU in conjuncture with the MSI Wind's stock PSU? Just rip it out?

The whole power inverter thing just seems a lot less complicated to me, couldn't I use a ground loop isolator to get rid of any noise/engine whine? (which I still had while using the P1900 in my ranger

)

DarquePervert · 07-30-2009, 03:40 PM

1 - If you have ground loop issues with both the inverter and the Carnetix, then there's another issue besides components being grounded properly. A Carnetix is no guarantee of resolving "noise in the system" problems. It will simply take one potential cause out of the loop.
And a ground loop isolator will only help you if the noise issues are a result of a ground loop, as the name implies.

2 - You likely wouldn't rip anything out. Chances are the "brick" portion of the power supply indicates a single output voltage. If the Carnetix can supply the same voltage (or darn close such as 20v instead of 19.5v), then you simply replace the "brick" with the Carnetix unit.

Warmachine · 10-11-2009, 12:31 AM

I know this thread is a little over 2 months old but I am curious what came of it. I have a MSI Wind Nettop that I wanted to use for my carpc but was facing the same problems you have with wanting it to boot on ignition. I was curious if maybe a dc laptop cable might fix the dc-ac and back to dc again issue. If no one replies within a few days I will open a new thread. Thanks!

DarquePervert · 10-11-2009, 07:56 AM

It's not a cable. It's a replacement for the power brick.
If there's a laptop car adapter that will work w/ the MSI Wind, it will only power the laptop from the car's electrical system and eliminate the inverter. It does nothing for startup or shutdown control of the PC.
You can go that route and get a standalone startup/shutdown controller, sure. But if you're going to drop the money on an auto power adapter and a SSDC unit, then you might as well get an all-out DC-DC PSU that has all that functionaility built-in.

You might try reading the FAQs, Warmachine.
This is is all outlined in the FAQs, the link to which is buried where nobody can see it, unfortunately.

http://www.mp3car.com/vbulletin/advfaq.php

Warmachine · 10-11-2009, 11:51 AM

Ha! Im sensing a bit of sarcasm there Darque. I have seen the faq in its deeply buried location. I just wasnt sure how to implement it in my application. I actually did a significant amount of research and solved my own problem last night. I saw the advice for the carnetix p1900 but was unsure of how it worked physically. I understood the theory and how a dc-dc power supply worked just not in my application. Case solved though!

Thank you for your help!

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