PSUs in parallel

[ian209]

Ok, this sounds crazy, but I'm planning on upgrading my car amp for my subwoofers to an 800watt amp. (This setup is in my house).

Only prob is, i don't think my Mushkin XP650w PSU has got enough juice to run it. SO, I'm thinking of buying 2 or more computer PSUs with a strong single 12v rail to power my rig. Now the real questions are:

1. is it safe to wire 2 computer PSUs in parallel?

2. how will i do this?

3. How about wiring 2 or more +12v rails from one PSU together?
Example: I have a PSU with quad 12v rails each with 20amps. is it possible to wire all rails together SAFELY and get a total of 80amps output?

Thanks in advanced!

 

[dch222]

I'm severly pissed off with people like you thumping past my house all night so sorry, I ain't going to help on the grounds of potential aural pollution.

 

[Nigel Goodwin]

Well he did say it's for home use!.

However, I would suggest getting a proper home amplifier, and not playing with the toy in-car stuff.

 

[ian209]

I'm severly pissed off with people like you thumping past my house all night so sorry, I ain't going to help on the grounds of potential aural pollution.

lol, im only 15 years old and don't have a car. Don't even plan to get a car either, so no pollution there.

BTW, I've heard that bad things can happen when you pair a car subwoofer with a home amp. One is that the home amp is usually suppose to output at an 8ohm impedance, and car speakers are normally 2ohms - 4ohms. Mine are 4 ohms. Last time i did it, i fried my old pair of titan 10" subs.

 

[Sceadwian]

That's just not paying attention to what you're doing. If you're into power audio home or car and you don't know what the impedance of the speakers or amp you'er using is you probably shouldn't be touching any wires =)

 

[audioguru]

The power supplies are only 12V. A car has 14V which makes much more power in the amplifier.

12V supplies have slightly different output voltages. If you connect them in parallel then the one with the slightly higher voltage powers the entire load and the one with the slightly lower voltage does nothing except laugh at the other power supply burning because it is overloaded.

 

[ian209]

The power supplies are only 12V. A car has 14V which makes much more power in the amplifier.

12V supplies have slightly different output voltages. If you connect them in parallel then the one with the slightly higher voltage powers the entire load and the one with the slightly lower voltage does nothing except laugh at the other power supply burning because it is overloaded.

yes i know, the car amps are supposed to be powered with 14.4v. My computer PSU i have and plan to buy all have adjustable POTs for the 12v rail. It goes up to a max of 14.4v, so i just have to crank the POTs in each PSU to the max.

Also another question: What if i have a PSU with say quad 12v rails. Will it work if i put them all together in parallel? Well, to be a little more specific, do the rails operate on the same regulator, or do they each haver their own separate regulator?

 

[Sceadwian]

They run off the same regulator, I've never seen a PSU with seperate 12 volt rails, maybe some high end fault tollerant ones but it's not likley you're using something like that. Jurry rigging something like this is a good way of blowing up your power supply(s) and starting a fire, especially at 80 amps. Even if you used multiple power supplies the current sharing between them will probably not be acceptable, not to mention the high frequency noise would be horrible because it's a switching supply.

 

[Hero999]

If they are current limited and reduce their output first before shutting down the paralleling them should be a problem. Just adjust them to exactly the same output voltage and when one starts to overcurrent its voltage will drop slightly and the other will start taking the strain.

 

[ParkingLotLust]

They run off the same regulator, I've never seen a PSU with seperate 12 volt rails, maybe some high end fault tollerant ones but it's not likley you're using something like that. Jurry rigging something like this is a good way of blowing up your power supply(s) and starting a fire, especially at 80 amps. Even if you used multiple power supplies the current sharing between them will probably not be acceptable, not to mention the high frequency noise would be horrible because it's a switching supply.

Higher-end PSU's (like the 1kW one, forget who makes it) have multiple 12v rails, to prevent voltage spikes (evens the draw over the rails, instead of all on one rail)

 

[ian209]

something like this:
**broken link removed**

would it work?

 

[ikalogic]

have anyone imagines what will happen if one of the 2 PSU is dead..? the other will follow imediatly right?

 

[audioguru]

A smart psu simply shuts down when it is overloaded.
A stupid psu just blows up.

 

[ian209]

well that PSU does have overvoltage/current protection, so i guess its worth a try.

 

[dch222]

im only 15 years old and don't have a car. Don't even plan to get a car either, so no pollution there.

Sorry for the rant Ian, I misread your post probably due to my haste and excitment at being about to leave work.
When you said "my car amp" I assumed you had a car.

Welcome to the forum. They're not all grumpy old men like me fortunately.

 

[audioguru]

Of course we are all grumpy old men. We scared away the happy ladies long ago.

 

[ian209]

Sorry for the rant Ian, I misread your post probably due to my haste and excitment at being about to leave work.
When you said "my car amp" I assumed you had a car.

Welcome to the forum. They're not all grumpy old men like me fortunately.

lol its ok. Anyways, any suggestions for my problem? I will soon test running parallel with dual 12v rails on my Antec Smartpower 2.0.