Using M2-ATX as a point of load converter

**nasa** · 01-01-2008, 04:15 PM

Hi,

I have a spare M2-ATX, that I want to use to power my usb hubs and my dvd drive. I plan on powering the M2-ATX from the 12V line from my OPUS 120 (it's switched). This leaves me with 2 questions:

1. Any suggestions on a small enclosure for this? O will I have to fabricate something?

2. Does the M2-ATX power on the 5V line even if it's not connected to a computer?

Any help is ALWAYS appreciated.

Nasa

**2k1Toaster** · 01-01-2008, 05:37 PM

I think the best way is the connect the M2's power line to the car system not your opus, then connect the +12v from the opus to the switching line on the M2, and ground to car's ground.

Then short pin 14 to a ground pin on the ATX plug. Now it will be on anytime the Opus' 12v line is live. I would also set it to dumb-psu mode so it isnt holding things on longer and so on.

**nasa** · 01-01-2008, 06:09 PM

2k1Toaster,

Thanks for the input. I can see how that setup would work. But, If I may ask -- why power from the battery vs. the Opus 12V Aux Power (J7) connection? (At this point I can easily follow you instructions -- just trying to be more educated)

Nasa

**Bimmerstyle** · 01-01-2008, 07:55 PM

I don't have any experience with the opus but if it has a 12V aux it's probably regulated and takes it power from the PSU 12V line. So if you connect the M2 to that, it would cause the current the opus has to deliver rise, keeping less reserve for powering the rest of the PC.

The M2 is specialy made to be connected to unregulated 12V so there is no need to make your opus work harder then it needs to.

When you connect the opus' aux power to the M2's switching line, the M2 draws only a little amount of power from the opus. The main amount of power now is drawn from the cars electrical circuit directly keeping your opus clear of it.

**2k1Toaster** · 01-01-2008, 08:38 PM

Originally Posted by Bimmerstyle

I don't have any experience with the opus but if it has a 12V aux it's probably regulated and takes it power from the PSU 12V line. So if you connect the M2 to that, it would cause the current the opus has to deliver rise, keeping less reserve for powering the rest of the PC.

The M2 is specialy made to be connected to unregulated 12V so there is no need to make your opus work harder then it needs to.

When you connect the opus' aux power to the M2's switching line, the M2 draws only a little amount of power from the opus. The main amount of power now is drawn from the cars electrical circuit directly keeping your opus clear of it.

pretty much exactly.

**nasa** · 01-01-2008, 09:27 PM

Thanks Guys,

appreciate the inputs!

Nasa

**nasa** · 01-04-2008, 01:32 PM

Well,

I lied... I said I had 2 questions.... But know I have a third.

Presently I have my usb hubs and dvd slimdrive powered via an inverter. The dvd drive doesnt' seem to like the inverter, so I am replacing it with the M2-ATX as descibed above. I had the inverter installed by a professional (as I have/had some hand issues -- and was very busy at the time). The inverter comes on/off with the starting of the car - talking with the installer, his best recollection is that he used the ACC line (or possibly a spare fuse). So to keep things simple (I like KISS) I was going to pull the inverter and use those lines to power the M2-ATX. Is there any issue with doing that? Searching the forum seemed to suggest a lot of people don't think that's a good idea.... But the only problem I gathered from searching was that power maybe discontinued during car startup. Is/Are there other issues to be aware off.

Nasa