Dual PSU with delay start?

[BellaCroix]

I've read through the Dual PSU sticky and was happy to find the diagram for the relay method to turn on the second PSU but I'm wondering if anyone has seen a diagram or commercially available product that also incorporates a delay switch?

I'm planning on running an old 350w secondary to my main PCP&C to pull some load from "extras" on the next build. The secondary PSU will only be powering 2 watercooling loops (2 pumps, 5 fans, 2 fan/temperature monitors) and 4 cold cathodes.

I'd like to find an automatic way to have the watercooling loop turn on about 5-10 seconds before the PC actually turns on to ensure that the watercooling has had a chance to start before the PSU fires.

I've seen the "stay-on" mods to keep a HSU fan running after power-down and wonder if there's anything that works the opposite way.

Thanks

 

[[21CW]killerofall]

The only thing that I can think of is to wire a switch connecting the 2 wires that you need to short out in order to start the 2nd PSU. It should cost you only a few pennies for the switch and wires (a little more if you want to solder it (which I would suggest) and you don't have the supplies).

 

[BellaCroix]

The only thing that I can think of is to wire a switch connecting the 2 wires that you need to short out in order to start the 2nd PSU. It should cost you only a few pennies for the switch and wires (a little more if you want to solder it (which I would suggest) and you don't have the supplies).

From your description it sounds like you're recommending a seperate switch to turn on the loop before hitting the button to actually turn on the actual PC power. I'd thought about that and wouldn't really mind that for the most part. What I'd be concerned about it my GF deciding she wanted to break the rules and use my PC without turning on the WC loop first or me coming home drunk and deciding to drunk-mail an ex or something and forgetting to do it myself.

Was trying to figure out a way to do everything with the one main power switch. Throw the switch, have the loops and fans fire, then 5 seconds later have a delayed relay turn the actual PC on.

Something like that would allow single switch access, guarantee that someone won't forget to turn on the water, and get all the juices flowing before the CPU had an opportunity to build-up too much heat before the pumps started moving.

 

[jellyhead]

You wire in a big-ass claxon & flashing light if the other PSU is open-circuit? Handy for alerting you to water failure down the road, too Knowing nothing about electronics, I couldn't advise you further on this!

 

[rodsfree]

Guys - you can do what you want with a big asses capicator or a standard 555 timer that you can get from Radio Shack. The Cap method is not as exact as the 555 but it requires fewer parts and soldiering.

RadioShack even has the books.

 

[BellaCroix]

Guys - you can do what you want with a big asses capicator or a standard 555 timer that you can get from Radio Shack. The Cap method is not as exact as the 555 but it requires fewer parts and soldiering.

RadioShack even has the books.

Excellent! Thanks! I'd never heard of a 555 before and just had to Wiki it. From the description there it sounds just about exactly what I was looking for. Now to see if I can find a 12v version or if it's going to get really complicated. So let me see if I understand how something like this would work:

Secondary PSU turns on (along with the WC), 555 timer activates on power from that PSU, 555 timer trips 5 seconds later and activates a monetary relay, relay sends an "On" signal to the MoBo power header?

Who wants to make a couple bucks building this thing for me?

Looks like it's time to hit Radio Shack (You've got questions - we've got blank stares).