M3-ATX 125 watt Smart Automotive Power Supply

**Bunter2000** · 06-19-2008, 03:50 AM

I bought a PC 12V power supply from a local supplier in Brisbane, Australia (Jaycar) it is nothing fancy but for under $100 and 250Watts it works well. I have opted to have more control over the PC by selecting when I want to use the PC with the M3 it is really designed to auto start even if you do not want the PC on.

I have an E34 BMW and am happy with the original head unit so I chose to use am FM transmitter as my interface to the radio. It may not sound as good as direct connected but for my personal use it good enough for me. I have a switch on the dash that connects through a 12Volt ignition supply and another momentary switch to start the PC.

I port the audio to the touch screen speakers and the FM transmitter so if I just want to listen to the radio but require the GPS I can select a local station on the radio and turn up the monitor volume to hear navigation info.

I can turn off the PC manually or via a timer (also jaycar), when I turn off the car the timer kicks in and holds the 12V supply on for an additional 15 seconds and at the same time a relay momentary pulses the pc switch line which starts the hibernate process.

The standby current when all is off including the timer is 300 microamps so the drain on the battery is far less than the security flashing LED in the radio.

**fallingbear** · 07-14-2008, 10:23 AM

hey bunter,
could you please tell me what that power supply was called from jaycar??
i tried looking it up, and could not find it on their website?
thanks
fbear

**Bunter2000** · 07-15-2008, 06:36 AM

Originally Posted by fallingbear

hey bunter,
could you please tell me what that power supply was called from jaycar??
i tried looking it up, and could not find it on their website?
thanks
fbear

II miss quoted , its 205 Watts not 250 anyway its a Powertech 205W DC-DC ATX power supply, on the bottom of the box is a part number ?? XC-4876.

I know you can find it on the jaycar website.

Hope this helps

**fallingbear** · 07-15-2008, 08:39 AM

thanks bunter,
i rang them today, found it thanks,
how have you found the unit??
for $99 cant complain, but would be good if it is a good unit as well?
cheers
fbear

**Bunter2000** · 07-16-2008, 01:45 AM

Falling Bear,

So far I have not had a problem with it. The only thing I dont like about it is that it does not regulate the 12 Volt line. I was testing my PC on the bench using a 6 Amp battery charger and decided to monitor the 12 volt rail and the 12 volt rail fluctuated from 11.5 to 13.4 volts under varying changes in load caused by the PC.

When I checked the bios it also reflected similar changes in voltage, but I had no problems at all with the operation and left it going continuously for 24 hours and had no sign of any problems.

As it is just a power supply and you want auto cut off with ignition you will need a couple of relays and a timer to hold the 12v battey onto the power supply until the PC hibernates.

I can hand draw my setup for you if you want

Hope this helps

**Jistari** · 08-06-2008, 12:17 AM

Oddly enough, I switched from the Jetway MB that was giving me problems to an MSI (fuzzy GM1) and my M3 atx is working perfect now. Just thought Id update since I posted that I had problems with it here.

**fallingbear** · 08-06-2008, 03:41 AM

thanks bunter!!
sounds all a bit too much hoo har for me though, i am thinking of just keeping my laptop for now, and then when the ssd computers come on line, will then update??
seems it wont be too long till an ssd com is here, with everything in it, the size of a cig box?? self powered with its own solar panel on top??
will just need a screen then?
even then, the small hand held projectors might do the job??
future looks bright
cheers
fallingbear

**coreyspeed** · 11-06-2008, 06:32 AM

i am think of getting one of these power supplys and would like to now if it has a fuse and if it is 1u complaint, i.e fits in a server case.

**Bunter2000** · 11-06-2008, 03:03 PM

Coreyspeed

The power supply will need mount points that are non standard however it is possible (never tried) it may replace the board in a standard 200W power supply box that is found in most ipx and low profile mini atx cases.

The board is L120 x W60 x H22 has a 4 pin DIN socket at one end for 12Volts in and a standard 20 Pin ATX power connector the other end.

I hope this helps

cheers

Bill

**tobmag** · 04-16-2009, 04:55 AM

Ive been running my car PC with the M3-ATX for some weeks now and I know that my car battery isnt the best. Overnight it will drop below 11,2volts and the M3 will shut down completely. However when startning the car it will not switch on again when the engine is running......I have luckely a switch that I can manually switch the computer on-off in the front of the car and by doing that the PC starts up again. Shouldnt the M3 do this automaticly when the voltage is ok again?

BR//Tobmag