M2-ATX wiring question

SkaLou · 02-24-2008, 01:01 AM

I've got a solution wired in right now that works fine, but the powersupply is in "dumb" mode. I know that there's a way for me to take advantage of more features of the M2-ATX, I just don't know how. I read the manual, but I'm not much of an electrician. Wiring up my car the way I already did was tough enough for me (meh, not really, I just don't know how to do something more advanced).

Here's a picture of what I have:

Can someone add in some quick lines to show me what I should be doing? Or just give me some advice. I guess what I have works fine, so it's not really a big deal.
Template:

Much appreciated,
Lou

jumbodogs · 02-24-2008, 06:07 AM

Think I know what you want to do but let ask a few questions first.
1. Why do you have standard on/off switch? Do you want to be able to get in car and not have PC start?
2. Do you just want the computer to start when you turn on the car and have a momentary button in case your computer hangs or you need to do a restart?

Standard on/off switch is helpful to have for the few times year when maybe car is to be serviced or what not. I am guessing that you want an on/off for this reason so what you probably want to do is leave your on/off switch the way it is and then connect a wire to jumper 8 on M2-ATX to your motherboard powerswitch jumper. Then connect momentary switch to jumper 9 on the M2-ATX.

This way you can leave normal switch in ON position most of the time and you will have momentary switch in case you need restart or computer hangs.

Here is a Link to manual for M2-ATX

DarquePervert · 02-24-2008, 08:13 AM

SkaLou,

Here's what you want to do:
1 - Ditch the regulator. It's not needed at all, as the M2ATX has built-in regulation.

2 - Run +12v straight to the (+) terminal on the battery or distribution block. Don't forget a fuse!

3 - Run GND to your grounding point or the (-) terminal on the battery.

4 - Run IGN to an ignition-controlled power source. Now, this can vary from vehicle to vehicle, but sme likely sources are a cigarette lighter, an amp remote lead or a switched line for teh stereo harness. THis line can be very high-gauge (thin) wire, as it doesn't transmit any power.

5 - Run the two-wire lead from the M2ATX to the power switch headers on your motherboard. If you have a power switch conencted to the motherboard, remove it. The M2ATX will control power on & power off of the PC now.

6 - Set the jumper settings to turn the PC on/off with the M2ATX witht he timing setup you prefer.

7 - If you want the ability to turn the PC on or off manually (with a switch), then wire a switch on the IGN line. It will act as a valet switch. Basically the switch will control current on the ACC line (or IGN line - they mean the same thing). Since the M2ATX senses that voltage and uses the state o that line to determine whether to power up or power down, you have that control. If the switch is off when you start the car, the PC will not boot up, because there won't be 12v on the IGN line for the M2ATX to sense to initiate bootup.

Make sense?

Ramanator · 02-24-2008, 11:46 AM

Quote: Originally Posted by DarquePervert

SkaLou,

7 - If you want the ability to turn the PC on or off manually (with a switch), then wire a switch on the IGN line. It will act as a valet switch. Basically the switch will control current on the ACC line (or IGN line - they mean the same thing). Since the M2ATX senses that voltage and uses the state o that line to determine whether to power up or power down, you have that control. If the switch is off when you start the car, the PC will not boot up, because there won't be 12v on the IGN line for the M2ATX to sense to initiate bootup.

Make sense?

Question DP;

Is the current on the ACC line Constant or is their a pulse just at start ups?

SkaLou · 02-24-2008, 03:12 PM

I should have been more clear. I will make a better, more detailed drawing of my setup. Darque, you're definately sending me in the direction I need to go, jumbodogs, thank you as well. I've got essentially all of my wiring in place, and my system works as it is.
Here's what I have:

I previously had an NTE933 in for the PC, but I took that out when I got the M2-ATX. The other regulators are for other devices. I put everything on one switch so when I get in the car, I can just flip a switch and everything turns on. Should I do as jumbodogs said and simply move my push button over to the PSU, and the PSU to the motherboard? Or is there more I should be doing to take full advantage of the features of this PSU? I mean, how I have it, it works (well, it should in theory, the PSU is still in transit). All the wiring is in place like this, but if I need to I can switch it to have a better setup.

DarquePervert · 02-24-2008, 03:31 PM

Quote: Originally Posted by Ramanator

Question DP;

Is the current on the ACC line Constant or is their a pulse just at start ups?

The current on the ACC line will be constant.
Basically the M2ATX (as well as other SSDC and PSUs that incorporate a SSDC) senses the current on that line and the circuitry will determine what to do.
If the PC is off and the ACC line goes hot, the PSU sends the signal to the motherboard to initiate bootup.
If the PC is on and the PSU senses 0v on the ACC line, it will press to button to initiate shutdown.

A pulse is sent on the two-wire lead to the motherboard to initiate boot up. Basically it simulates a press of the power button.

Quote: Originally Posted by SkaLou

I should have been more clear. I will make a better, more detailed drawing of my setup. Darque, you're definately sending me in the direction I need to go, jumbodogs, thank you as well. I've got essentially all of my wiring in place, and my system works as it is.

I previously had an NTE933 in for the PC, but I took that out when I got the M2-ATX. The other regulators are for other devices. I put everything on one switch so when I get in the car, I can just flip a switch and everything turns on. Should I do as jumbodogs said and simply move my push button over to the PSU, and the PSU to the motherboard? Or is there more I should be doing to take full advantage of the features of this PSU? I mean, how I have it, it works (well, it should in theory, the PSU is still in transit). All the wiring is in place like this, but if I need to I can switch it to have a better setup.

There are a number of routes you could take.
IMHO, the simplest would be to power everything from the M2ATX, assuming it has the oomph to handle all your devices.
Wire it all up the same way I described previously. One button makes the ACC (or IGN) line go hot and the M2ATX powers up all your devices.

There are other methods of achieving what you want using relays, POL power supplies and so on, but this would be the simplest.
Again, others may disagree or have a better solution for you and your setup. Hopefully they'll throw you some suggestions, too.

SkaLou · 02-24-2008, 03:38 PM

What would be the advantage to that? then I'd just be loading up my PSU more... and I'd have to run a lot more wires to my other devices...
I'm sure there's an advantage, or you wouldn't tell me to do it. I just fail to see what it is :s

DarquePervert · 02-24-2008, 03:40 PM

Quote: Originally Posted by SkaLou

What would be the advantage to that? then I'd just be loading up my PSU more... and I'd have to run a lot more wires to my other devices...
I'm sure there's an advantage, or you wouldn't tell me to do it. I just fail to see what it is :s

One button to turn on the LCD, the USB hub, the PC and all your peripherals.
That is what you're ultimately trying to achieve, isn't it?

SkaLou · 02-24-2008, 04:14 PM

I already have that though almost, except it's a switch, not a button. The LCD and USB hub power up when the switch is flipped, the PC powers up on the push button. It seems like a ton of extra wiring for a slight increase in convenience.

Also, two more things I just realized. I stupidly didn't order a P4-P4 adapter for my M2 which should arrive tomorrow. I'm ITCHING to install this thing... What's a website I can order one and have it overnighted for about 10 bucks or less. If one doesn't exist, I'm seriously just going to scrap two 200 watt power supplies I have and make my own.

Also, reading another topic made me realize: I only have 20 amp fuses in my line because I originally just added up the draws of my regulators: 5A & 3A, plus a bit extra for the LCD and a bit extra for whatever. Now I don't have a regulator on my PC, and I'm not sure how much it's going to draw. I don't know how to do conversions, but the system is going to use ~80 watts. Do I need beefier fuses, or should I be safe? I'm thinking I'll be safe because I know 5A would give me 60 watts, so even though I can't convert I'm going to guess 80 watts is going to use 6.66A. Is that correct? If so I think I'm good... but I'm no expert.

Also DP, thanks so much for your extremely fast responses!

ronjon228 · 02-24-2008, 07:00 PM

I'm fairly certain that the M2 ATX is 15 amps of draw. You should be able to use that for your calculations. So 15A (M2), 5A and 3A for regs, and then a bit extra for the PSU.

SkaLou · 02-24-2008, 08:50 PM

Thanks, that sounds about right. I am thinking it's V*A = W, right? so 12V * 15A = 180, the M2-ATX is 160W, so that sounds like a fair rating. So I'm only drawing about 80 W, so my calculation of 6.66 A would be a correct average. I've also got the 3A max on my USB hub, plus a small amount (not sure on the exact rating) for my LCD. That's only about 10A, so I am pretty sure I am not going to have any problems with a 20A fuse. If it turns out I do, then I guess... I'll just go to radioshack and pick up some 30A fuses. Not so hard!

Now, for my P4-P4 cable, I scrapped some powersupplies because I didn't feel like waiting around for one to be shipped. It's a one to one deal I assume as far as pin correspondence?

DarquePervert · 02-25-2008, 06:06 AM

Quote: Originally Posted by SkaLou

Now, for my P4-P4 cable, I scrapped some powersupplies because I didn't feel like waiting around for one to be shipped. It's a one to one deal I assume as far as pin correspondence?

Yup.

jumbodogs · 02-25-2008, 08:01 AM

I maybe wrong but I think you should decide on the wire size based on the total amount of wattage that is going to be drawn over the line that you have for your PS and whatever else is running on it. Then divide that number by the amount of volts 12. This will give you the amount of amps you will be using and then you can look up on a chart the wire size you should be using and the fuse that goes with that wire size.

From my understanding the wire always determines the fuse size. For example 12awg wire is rated for 20amp fuse based on the chart found on this page. The fuse is there to protect the wire.

As far as hooking up the M2-ATX I believe you need to at least have jumper 8 connected to the motherboard power switch connector or the M2-ATX will not turn on the computer. Jumper 9 is only there to give you the option to have a normal power switch in case computer hangs or what not.

SkaLou · 02-25-2008, 09:27 AM

But can't you always use a lower fuse than the gauge of wire? That was my understanding. I used uhh, like, 8 or 10 gauge wire for almost all of my wiring, and a small amount of 12 or 14 in some places (switches, where it was impossible to solder the lower gauges on). I know it can only take as much power as my weakest point, but I only used the low gauge wire to ensure I wouldn't end up with any accidental breakage.

So if I'm using 8ga, that's 60 amps, 10ga that's 30 amps. Using a 20 amp fuse, I should be okay, because the fuse will blow before the wire is maxed out. If I were to use, say, 10ga and a 40 amp fuse, I am pretty sure if it short circuited, the wire would just heat up with 30 amps of conductivity (and more) causing it to overheat, maybe start a fire, almost definitely do some serious damage to my car, if not the plastic molding it's running beneath, then my battery.

In fact, I just read the bottom of that chart after typing this:
"These are the recommended maximum fuse rating for the corresponding wire size. Using a smaller fuse than what's recommended here will be perfectly safe." I think that pretty well settles that.

I am going to go check out what gauges I used though, sucks if I used 14 cause I should probably rewire my switch then.

PS- you guys are freakin' awesome.

FusionFanatic · 02-25-2008, 10:47 AM

Quote: Originally Posted by SkaLou

I got the M2-ATX. The other regulators are for other devices. I put everything on one switch so when I get in the car, I can just flip a switch and everything turns on

as darque said, you can power the USB hub and monitor directly from the M2-ATX (as low as it has enough power), but that would still require running power wires from the trunk to your dash/glovebox.

or you can power them right off the cig lighter wires so you won't have to run power wires from your trunk. use a relay to turn them on/off with the car's ignition (unless your cig lighter is already ignition switched).

it's fine to have a switch up front, but it shouldn't be directly powering anything. either switch the IGN line going to your M2-ATX, or use a relay to switch power on/off, and use your dashboard switch to control the M2-ATX input (or relay). this way you can keep your wire gauges small. there is no need to have 8awg wire running all over your car, especially since you're reducing it to 14awg at the switch points. run your 8awg wire into the trunk to power the M2-ATX and stop there, you can use thin gauge wire to control the M2-ATX and/or relays.