looking to power a computer from car batt...any suggestions?

You may have seen me asking around for random stuff...but I am doing a project for school in which I am building a robot. I have the mobo, processor, and hd already. I am now trying to figure out the best way to power everything off of batteries. I am thinking that I should use a 12V DC-DC power supply (for ITX car mp3 players). I wanted to know what would be the cheapest and safest (won't kill mobo) way to do this? I figure that in all I will need to run 1hd, a few (1-3) usb devices and 1 pci card.

The specs of everything so far is:
S635MP mobo with the 800MHz C3 proc (yay for low power)
I hope to have either 2x256 or 2x512 PC2100 (if I get some from classifieds)
4GB hd
802.11g wifi card
1 or 2 webcams (USB)
and a random parallel port device (motor controller)

Also, should I bother getting something to monitor the voltage from the batt and shutdown the mobo when it drops to a certain level...or can software do that for me?

I have asked about power sources, and many have suggested that a car battery would be more than enough to run this setup for a while (few hours). Anyone want to say otherwise?

http://www.mp3car.com/store/

http://www.mp3car.com/

Check that out, they can probably answer all of your q's

You really don't take advice over PMs well. Have fun paying $150 at that store.

Good luck.

No, it has nothing do do with not taking your advice...it is just that I don't want to miss something and blow everything up. I kinda wanted to get a few different opinions before throwing everything together and flipping the switch.

Nephewkp said:

Also, should I bother getting something to monitor the voltage from the batt and shutdown the mobo when it drops to a certain level...or can software do that for me?

Click to expand...

2 relays + variable resistor + capacitor can do this.

hehe, just for fun eh?

opus power supply.

they are the best DC/DC PSU youll find, but they arent very cheap, and they have functions you wont use.

their designed to work for a car PC, so they cater to that.

other downside, only 150watts, or atleast thats the biggest Ive seen, and that even is like 100$. but dont worry, apparently its an incredably efficient 150watts.

make sure your total draw is as low as possible cause running off a car battery sounds like a recipe for very short run time. and be careful cause I think fully cycling a car battery down alot is hard on it.

^^^
Get a yellow top battery.

if the battery is going to be discharge alot and charged alot , look in to a deep cycle battery. there made to do that

yeah, I was thinking about that And I decided to use a voltage monitor/regulator to send a shutdown request to the computer when the voltage drops below a certain point. Of course the point to which the circuit is triggered will determine the runtime and the wear/tear on the battery. I think that not draining the battery fully using something like this will allow for the battery to have a longer lifetime.