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[oxjeremy334]

It sounds like it could work, but I am wondering about the amps (but then again, I haven't really looked at the psu in depth to see what all is regulated and where).  But if it goes straight from the ac to the dc power converter, then I think that it should work.  I would definately get out a multimeter to make sure that you were getting the same output from the plugs whether the ac or the dc from the car is connected.  I'll check up on this post, as I was thinking of putting an xbox in my car, and this would be a better way than to have a ghetto power converter somewhere....and I also failed to hook up speakers in my car so I just have power running everywhere.

[Tron[ADS]]

QUOTE(flashfreak @ May 9 2005, 08:01 AM)

I've fiddled with power supplies before and have a fair knowledge. About in the middle, theres the AC>DC convertor, where it goes from 110 (or 240 here in aus) to 12. I think this is the one spot where the 12 volts starts. I'd have to put a fuse on the positive wire as well, I'm not stupid

[flashfreak]

hmm...thanks for all the help guys. its made me think more about it.

such as the 12v ac problem, and it switching earlier or later, whichever, i'd need a bit of help to find. i have a fair skill of electronics but definately not enough to do this on my own, i'm only 17.

some things i have thought about...
the 14v from battery when car is on: i know exactly why this is. when the car is on, the alternator is going which provides the 14v to the battery, 2v more than what the battery will hold so it will charge. you probably knew that but i'd point it out just in case, and for anyone else who wants to know. i'd have to find some way to keep this at 12, unless its not really necessary.

a switch from the power: just in case that 3.3v drains down the battery if the car is not used in a while.

grounding and interference: i would most likely just try to get the ground points from the mobo and run them to the car chassis. is that all i need or more? maybe the black wire from the psu?

heres the setup i plan to have....: i'm gonna get an xbox, toss the dvd-rom most likely as i'll need space for my new custom case/parts holder, all i'll really be keeping is the mobo, modified psu, hard drive and i'll probably redesign the p/e board with just a power button and maybe a single led for when its on and maybe only the first set of controller ports as i won't need them all. just looking to use this for a media player. on my custom case (which im planning to make out of thick plastic somehow) will have the power button and colour lcd screen in the front (no idea about these but will figure out later).

wanna know the funniest part? this setup is going in a '64 mini cooper van (the long ones) it was my bros and its been handed down to me for when i get my P's in july. theres not much space inside so i'm having to remake the case to fit in the dash cos theres really no other suitable place to put it.

so yeah, if some1 can address the above concerns, it'd be great. thanks!!

and sorry its so long!

edit: added a little extra i forgot about

[CKwik240]

QUOTE(flashfreak @ May 9 2005, 06:12 AM)

a switch from the power: just in case that 3.3v drains down the battery if the car is not used in a while.

grounding and interference: i would most likely just try to get the ground points from the mobo and run them to the car chassis. is that all i need or more? maybe the black wire from the psu?

You'll probably need to test the 3.3v draw, but I would speculate it would be no more of a draw than what an alarm or stereo uses for memory.  Considering PC motherboards use lithium batteries for memory and I've never actually replaced them, I'd expect the draw to be quite low.  Of course I am assuming that the memory power requirement is similar.

For ground, the metal chassis inside the xbox is all you will need to ground to the car's chassis.    The headphone jack I used requires that you drill a hole.  The jack itself is designed to ground against whatever it installs against if it is metallic.  This made it quite simple as I didn't even need to solder a ground.  If you build you're own plastic case of some sort, you may introduce potential for interference.  The Inside of the XBox is already well shielded as it is for the most part encased in metal within the plastic case.  It might be a better option to build a metal case if you go that route.  I would just leave well enough alone as long as there is enough room for the OEM XBOX case to fit in the car.

[Staple]

just wire int he flux capacitor an call it a day  

[flashfreak]

just spoke to a local guy who can do pretty much everything. i asked him if this was possible and he said its not, as all things have to come from the transformer and have to be exact.

somehow it didn't seem right, but i wish we had some1 who was a real electronics wizz here who would be able to confirm it.

bah, surely it has to be possible!

[Tron[ADS]]

I don't buy what your local guy says atall.
I am professionaly qualified in electronics, which I know doesnt make me correct all the time (I only said that to point out that I do have a small amount of expertise in such matters) , but I see no problem whatsoever in inserting your 13.8V after the DC conversion on the xbox power supply. I would imagine that the current transformer will provide about 15V to the various regulators, but running at 13.8V would cause it no problems whatsoever as long as its a higher voltage than the highest voltage required which at 12V, it is. You would have to cut the tracks to effectivly "lose" the earlier transformer and bridge rectifier. The remaining stages on the xbox power supply couldnt care less how its DC supply was produced, only that its actualy there for it to work with.

In fact, it probably wouldnt be too difficult to even build your own power supply, you would pretty much only need some voltage regulators to match the ATX pinout voltages (3.3V, 5V, 12V and ground). Doing this would lose the switching off and on facility of the xbox though, you could only really make it permanantly on, switched based on your car's supply.

Actualy thinking about the car's supply. I would be tempted, as its an oldish car, to take great care with your fuse selection, and possibly even regulate the supply before it gets to the xbox. Reason being that older car electrical systems tend to be a bit wild when the starter motor is being used - the voltage can drop significantly, which can lead to increased current draws. The Xbox PSU draws (from memory) around 80Watts, so a 6A fuse ought to be a safe value to start with. I would be tempted to put the xbox power lead on a cigarette power lead and plug it in when you want it, rather than leave it permanantly attached.

[flashfreak]

thanks for all that help!

i won't be doing it soon, as i don't have the cash. it would be easier to modify the current psu than make my own, and this way i could maybe even cut off the half that i don't need to save space and weight.

i'd need you to do a detailed diagram of where to cut and connect the battery to as i have no idea. you don't have to help with this, and i thank you for what you've done, but if u wanna continue helping then that'd be great

i'd have a main switch on the psu most likely just in case i need to save battery, which would also stop the starter motor problem. i'd have a fuse and i'm even thinking of hooking it up to the accessory switch in the ignition so it'll only be on when the key is turned, just in case.

i'd wanna put a battery level meter in the front for when im using it when the car is off or suttin, just to make sure i don't take it too low.

its definately not gonna be right first time. my thoughts are to get a little dc convertor to 12v for the powerpoint so i can test it inside. i'd need to find a intec or hip pad screen.

it seems like too much effort sometimes, but i still wanna do it.

[networkBoy]

QUOTE(Tron[ADS] @ May 9 2005, 11:53 AM)

Your have your Power Supply synopsis (if thats the right word to use here) a little mixed up. Your "AC>DC Convertor, where it goes from 240 to 12" doesnt exist. The first stage of a power supply is the 240 to 12V (20:1) step-down transformer. Although it is 12V (actualy it will be slightly higher), it is still AC at this point. A Bridge Rectifier is then used to convert the AC voltage into a rough DC voltage, then either an LC or RC filter is used to grab the peaks from the cycles. It is at this point that you would need to cut the tracks from the first stages and insert your 13.8V DC source. All voltages from this point on are generated by using voltage regulators...its all pretty standard power supply stuff, the only complications being the over voltage protection systems and the pin 14 switching mechanism.

[Tron[ADS]]

QUOTE(networkBoy @ May 10 2005, 04:57 PM)

Hate to say that you're still a touch mixed up.  What your describing is a linear regulator, not a switching supply.

Yes your quite right there, I was indeed describing a classic power supply, and assuming the xbox psu wasnt switched mode (Im not sure why I even made that assumption in the first place!)......So, would you agree that the second paragraph of my (2nd) reply is the way this chap now needs to go, ie create his own to match the atx pin-out voltages, taking care of course that every component is powerful enough to take the current flow an xbox will require.

[flashfreak]

Nah I've given up on that idea. It'd be great to do, but too difficult for me. I definately don't have the skills to make my own psu, as i'm only 17 and have no training, or money for parts etc.

So I'm just gonna go with the invertor as it'll be much easy. I feel kinda lame taking the easy way out, but its either the easy way or the really expensive technical way that i can't do.

Thanks everyone for the help, if some1 wants to continue this project, then that'd be cool!

[TrigunXBox]

May I suggest this post.
http://forums.xbox-s...opic=360242&hl=


And this 12V-12V power supply built for what you want.
http://www.logicsupp...products_id/285

[TrigunXBox]

One thing to note about the inverter. Most (and the cheaper one you get, the more it does it) give off a lot of RF noise.  Normaly, the radio will pick up much of it. And if the inverter is near the head unit or amp, you can get a hum.

I have a TrippLite 140 watt one I love because I can run my XBox and 15" Sammy LCD off it, but it blows out most AM stations.  

Test before you mount it.

[flashfreak]

Nah i don't listen to radio, and i won't need to with my setup. Here in aus, most of the radio stations that are newhere decent are filled with friggin pop music and all that other shit. I'm just wondering in a mini where i could mount it. Maybe under the passenger seat...hmm...