Diy Dc-dc Pc Power Supply , Anyone?

[CAR_LCD]

I will be putting a Computer in to my car, a cheap seteup ATX board witha 2000xp AMD , I kind of need some help on a DIY 12DC-DC PC power SUpply for my ATX board and one hardisk , I did some seach on the net, they have some premade product, but it's a tight budget project, so ..... had anyone done it or got any good source how ot make one? thanx

[JOE DIRT®]

buy a inverter to suit the computers power demands

[li_gangyi]

Well here's my shot at it...I found this some time ago on the net...instructions are not in English though...

http://web.singnet.com.sg/~a1265/SMPSU.zip

[MikeHunt79]

Originally posted by JOE DIRT®
buy a inverter to suit the computers power demands

Most inverters produce a sawtooth wave tho, which often results in noisy power being fed to the PC, which leads to buzzing from the speakers... DC-DC is your best bet. OPUS are good but pricey. You can build one yourself... I've done it. I used the sproggy design.

[li_gangyi]

well in the pc psu...it gets rectified to dc...so ain't it the same?? the inverters i got are square wave...which works pretty good on pcs...but dun try a fan...reduced output plus a lot of buzzing...

[MikeHunt79]

Originally posted by li_gangyi
well in the pc psu...it gets rectified to dc...so ain't it the same??

You would think so, wouldn't you? But the PC's PSU expects a sine wave to be put into to, so the rectification isn't as good when another sorta wave is put in. Try using a scope to look at the output from the PC's PSU when wired up to a square/sawtooth inverter and you will see what i mean.

I'm sure a sine wave inverter would work better, but they are pricey.

[li_gangyi]

how about beefing up the smoothing caps and using a faster rectifier?? IMO it just needs DC for the SMPSU to work properly...so mabe wad tt guy needs is just a DC to DC converter...assuming he doesn't try to run a printer off the supply...

[zx3chris]

hello,

i have a car pc in my car. i used the cheapest invertert i could find (newegg.com, $29 for 300w), produces modified sine wave (nearly square wave) ac. I used the cheapest PC power supply i could find. I have no noise issues. I have installed about 10 car pc's in various cars, and have gone the same route on each. Make sure to connect the PC power supply case to car chassis, and inverter case to car chassis. if you have any slight hum you cannot get rid of, get the external creative mp3+ usb sound card. it plugs into the usb port and prodvides female rc line out levels -- perfect to feed into an amp, and only costs $39, (the price of a OEM Autigy).

-chris

[none]

Here is where you want to look for your answers: http://www.mp3car.com/vbulletin/forumdisplay.php?f=11 Sproggy/ Mastero would be your best best for diy. I run a Sproggy 2.8+.