How can I do this?

[Smoblikat]

So I just bought my first car yesterday and I want to do some CRAZY stuff to it. I want to build a mini-ITX machine that sits under the front seat and displays to a screen mounted where the radio would be. my question is how do I power all of this? I am almost positive that my cigarette lighter plug is 12v @ 15a, so I have about 180w to play with (at 100% efficiency.) I designed a system that will max out at about 75w so that isnt a problem, but I was wondering how to safely connect the computer to the car. I know that computers obviously need consistent and clean power so I was wondering if I could plug in a UPS into the car then run my stuff off of that and use the UPS as a backup/surge protector.

Any advice would be great.

 

[dma0991]

How are you going to do that? The cigarette lighter is 12V DC. Most PSUs convert AC to DC. Unless you have a specific purpose PSU that runs on DC power and distributes them to the required PC voltages(3V, 5V, 12V), it's not possible to do.

There's of course ways to make it really work(expensive) but that is a method that doesn't involve the cigarette lighter. I am not quite sure what would you do with the PC in your car and how much performance do you really need but I'm certain a Raspberry Pi will get the job done. It works directly off the DC voltage cigarette lighter with a USB power attachment.

 

[Smoblikat]

How are you going to do that? The cigarette lighter is 12V DC. Most PSUs convert AC to DC. Unless you have a specific purpose PSU that runs on DC power and distributes them to the required PC voltages(3V, 5V, 12V), it's not possible to do.

There's of course ways to make it really work(expensive) but that is a method that doesn't involve the cigarette lighter. I am not quite sure what would you do with the PC in your car and how much performance do you really need but I'm certain a Raspberry Pi will get the job done. It works directly off the DC voltage cigarette lighter with a USB power attachment.

I just wanted to do this because I figured it would be a fun project. The system is a sandy pentium in an ITX board. I work with hundreds of electrical engineers, so I will ask them too. I was just wondering if you guys had any ideas.

 

[_Rick_]

In-car (battery) voltage (used to?) fluctuate quite a lot.
Probably outside ATX specs, at times.
With modern cars though, I would think that they got that under somewhat better control.
If you can splice out the radio's power source, that will probably have plenty of 12V juice.
Next step is to get the down-stream end of a normal desktop PSU. Essentially the 12V/DC part. You can either get one that's ready made, or take a two-stage PSU (many modern PSUs follow this design - transform to 12V DC, then splice 5V, and 3.3V off of that)
You may not even need both of those, but in most cases they will be free.
Re-encase the second stage of your new PSU, wire it into the radio cavity, and voilà, you can use the ATX/molex/Sata cabling, as you normally would. You may even have some OPP and OCP, depending on how that's implemented.

Disclaimer: I've never done that

 

[dma0991]

I just wanted to do this because I figured it would be a fun project. The system is a sandy pentium in an ITX board. I work with hundreds of electrical engineers, so I will ask them too. I was just wondering if you guys had any ideas.

It is definitely doable. There are servers out there that runs on pure DC. But to do that would mean changing DC to AC and back to DC on a switching power supply which will incur some losses in conversion, means its inefficient to do so.

The most efficient method would be to use a picoPSU that feeds off DC power and steps it down to the required voltages for the necessary peripherals. As to how will the cigarette lighter provide the required DC power to the picoPSU, I'll leave that to you to figure out.

 

[Smoblikat]

It is definitely doable. There are servers out there that runs on pure DC. But to do that would mean changing DC to AC and back to DC on a switching power supply which will incur some losses in conversion, means its inefficient to do so.

The most efficient method would be to use a picoPSU that feeds off DC power and steps it down to the required voltages for the necessary peripherals. As to how will the cigarette lighter provide the required DC power to the picoPSU, I'll leave that to you to figure out.

What about this:
http://www.newegg.com/Product/Product.aspx?Item=N82E16812120304

Run the UPS off of that as my surge protection/and input voltage regulation, then run the computer and LCD off of the UPS?

EDIT - Ill spend the extra 20$ to get a good brand.

 

[Smoblikat]

Also, what do you think of this screen for the car:
http://www.newegg.com/Product/Produc...82E16824638075

 

[serpretetsky]

http://www.mini-box.com/Car-PC-System-Components

 

[Smoblikat]

http://www.mini-box.com/Car-PC-System-Components

Thank you so much. That monitor in there is perfect for what I need, it costs half of what newegg wanted.

 

[lakedude]

A vehicle's voltage will fluctuate from 12v (or under depending on load) while on battery to 14 and change while charging.

You will need some kind of PS to smooth out those fluctuations for sure.

For $28 I run a laptop with one of these:

http://www.amazon.com/gp/product/B0067G4WPU