M2-ATX(-HV) 160 watt Intelligent DC-DC PSU

**rickd** · 08-05-2008, 11:16 PM

The difference is that the M2-ATX-HV version will regulate input voltages as high as 32 volts, rather than 24 volts as with the M2-ATX. It should not matter in automotive applications. An alternator might run voltages as high as the upper 14's when charging a battery. But extending the range to 32 volts makes it possible to use the supply in a 24-volt marine application, where the alternators might run voltages as high as 28 or 30 volts when charging the batteries.

The HV version is a bit less efficient, and is rated at 140 watts instead of 160 watts. It would appear to me, however, that with input voltages below 24 volts, the two supplies have the same power capability.

I wanted maximum flexibility--I'm using my Mini-ITX box as a battery-operated PC for ham radio applications in the field. If I need to run it for a long time, I might exceed the capacity of one battery. Sure, I could parallel two batteries, but paralleling batteries during discharge isn't a good idea--the batteries must discharge identically to keep the stronger one from trying to charge the weaker one. With the M2-ATX-HV, I can run two 12-volt batteries in series, which prevents the paralleling problem and gives me twice the amp-hours.

And with an 8-amp capacity on the 12-volt rail, it will run the display, too, providing regulation there as well.

For other who have mentioned it, the M2 does NOT come with the four-pin Molex-Molex P4 accessory power cable, but Mini-box does sell it separately. And, yes, I had to wait for it a couple of extra days, too.

And, yes, there seems to be a polarity issue in places I didn't expect, but my supply started working without me having paid close attention to what solved it. I did not, however, wire the main power cord incorrectly, and there is a rectifying diode to prevent reverse polarity, but I did fiddle with the PS-mobo power cord and may have reversed it. Without schematics, it would be hard to know what's going on. Some solid-state switching schemes are sensitive to polarity.

RickD, running an M2-ATX-HV with a Little Falls mobo in a Morex 3777.

**WuNgUn** · 08-17-2008, 05:17 PM

Can the M2 function with it unplugged from a mainboard?
I plan on using my M2 in the dash to power the monitor (12V) and a USB hub (5V)
Can I just trigger it on and off with the ign. lead and power it off and on?

**Acemaster24** · 08-20-2008, 08:37 AM

I have a question about the J4 pin in the manual it says the connection diagram J4 Battery - (negative) and in the logic diagram it shows ground. What do I wire to the J4 pin?? Thanks.

**RedGTiVR6** · 08-20-2008, 08:44 AM

negative and ground are the same thing....

**rickd** · 08-20-2008, 01:14 PM

Originally Posted by Acemaster24

I have a question about the J4 pin in the manual it says the connection diagram J4 Battery - (negative) and in the logic diagram it shows ground. What do I wire to the J4 pin?? Thanks.

The body, frame, and engine block of vehicles are grounded to the negative terminal of the battery. Therefore, J4 should be attached to any grounded part of the vehicle. You can also connect it directly to the negative post on the battery if you like.

My Morex case also grounds the case enclosure to the negative reference (the shell of the coaxial 12-volt receptacle on the back of the case is connected directly to the enclosure as well as to the wire that goes to the PSU). In that situation, bolting the case to a grounded portion of the car body and then just connecting J4 to the metal enclosure should work, but I always provide discrete ground wiring to minimize ground loops.

RickD

**FockMasterDan** · 09-05-2008, 02:50 PM

Originally Posted by WuNgUn

Can the M2 function with it unplugged from a mainboard?
I plan on using my M2 in the dash to power the monitor (12V) and a USB hub (5V)
Can I just trigger it on and off with the ign. lead and power it off and on?

My understanding was that yes it could, but so far I have not powered up my M2. I just have it for the purpose of powering an external HDD and any other accessories that need 12V regulated.

The instruction manual isn't very thorough and could someone walk me through how to get it up and running. I have the three power wires hooked up and the square 4 pin connector for the 12V power, but no juice. I know that it is getting power.

**FusionFanatic** · 10-05-2008, 05:02 PM

to run an ATX power supply without a motherboard you need to connect the "'power on" pin/wire in the main power harness to ground.

it's usually the green wire in the main power harness; it will be pin#14 on a 20-pin connector, or pin#16 on a 24-pin connector. (the M2-ATX uses a 20-pin connector). you can connect it to any ground wire in the harness by soldering the pins on the back side of the connector or by splicing the wires together.

**dotraw** · 10-17-2008, 02:42 PM

Having a problem with this PSU.

While driving (ignition ON ofcourse), the PC goes into hibernate and shuts down. Now when I stop the car and put the ignition to OFF, the PC starts up!
This happens every 2, 3 ignitions.

I have the jumpers set on P1. So after 60 secs the time limit kicks in and while the PC is still ON, the PSU cuts off all the power. NOT healthy for my box.

Oh yeah, the same thing happens if I manually start the hibernate procedure while the car is running -> PC shuts down, but when I turn off the ignition the PC starts for 1 minute.

Motherboard: D201GLY with 1.2ghz CPU
There are no heating problems and no problems with the car (have tried on 220>12V adapter). However while on 220V the PC didn't go to hibernate automatically at random times as in the car. Didn't test it much though... yet.

Any ideas?

ps: when the forementioned situation occurs, my LCD stays 'on' but only the LED is lit, the monitor is shut down. There is no way to 'reset' back to normal operation unless I disconnect the battery (+) for at least 10 secs. Superweird

.

**kelmk** · 10-18-2008, 05:00 PM

I'm having a problem with my M2ATX. I set the jumpers to A and B 5sec/never and I set my windows to standby on power switch. When I turn off the ignition, the computer seems to go into standby fine but the fans are all still spinning. I'm not sure if it's the motherboard fans or the case fans since I have the case on but I can hear it.
If I turn the ignition back on my computer resumes so I know the standby is working.

**serhat** · 10-19-2008, 10:40 AM

Hey,

I am new here and i dont have a lot of knowgled about car pc.
I bouhgt a car pc with M2ATX and a radio.
When i plug the sound cable from the pc to the radio i get strange voice when i press the gas pedal it increase when i give more gas. If i put my sound cable from my iphone to the radio there isnt such of problem. i have 2 groundloopers between the sound cable from the pc to the radio. I have alle the negative cables attached to the negative poll from the battery.
i am being crazyy i dont know what the problem is i know only 1 thing that the pc is the problem but dont know where the problem is.

I hope you can help me guys thank you very much