Thread: Power supply rails question

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I have a question about the number of rails on a computer power supply. If a power supply lists two +12 v rails (V1 and V2) both at 18Amps, does that mean that theoretically it can handle 36Amps total (i.e. you hook up a circuit to V1 and a separate one to V2)?

Thanks,
Jared

I'd say it's likely. Does it call out separate wiring for each of these output rails? Like, one loom of wires for V1 and another for V2. What are you using that pulls more than 18A? Wiper motors?

Well, I doubt I'm drawing that much current. I was just curious as to how it theoretically shoudl work. I dont' think this power supply has things listed on teh board (I've seen it on others though). This one does have three bundles of yellow wires coming from the pcb, and it is advertised with 3 12v rails so I'm guessing those would be it.

If you know for a fact that each line can handle 18A separately then yes you can combine all the lines and be able to handle 36A but if it is a total of 18A for the 12V then only 18A is available. For the power supply you are talking about I suspect its just one 12v supply with multiple wire bundles coming out so I would suspect that it can only handle up to 18A.

I hope that is somewhat clear...

The mod I found on this board only used one wire each for all the different voltages a supply gives out, which is what I did. It did mention to use 2 wires if you thought you were going to draw a lot of amps. I made 3.3, 5, and 12v out with single wires. Then I looked at a few other websites and noticed some of them recommended using every single wire of each color to attach to the binding posts or higher loads might burn the wires out. I'm not sure if this would really help. Fortunately I'm only using it to supply LEDs.