TL;DR: Is there anything out there to monitor power supply current draw? I 'd love to be able ...

[G+_John Mink]

TL;DR:

Is there anything out there to monitor power supply current draw?

 

I'd love to be able to tell my desktop isn't booting because "I'm giving her all she's got"

 

Background:

So I'm building a new computer (well, old parts but new machine)... Long story short I've spent the last few days trying to figure out why things were sporadically not working.

 

Eventually realized that it was the power supply not being able to pull enough current on a specific rail. Even though total power draw was underneath the max power limit, this power supply was clearly not designed for this setup >_<

[G+_Arcturus Lancaster]

If you want to monitor the wall line look up a device called 'kill a watt'

[G+_John Mink]

Arcturus Lancaster? I was actually using one of those, the problem is that I was under total power but the power supply can't perfectly distribute the power.

[G+_Travis Hershberger]

Trying to balance the load when using a multiple rail power supply can be painful, as you're finding out.  If you have the money available I'd look for a new single-rail unit.  How much power is it drawing from the wall?

[G+_John Mink]

Travis Hershberger I don't remember the exact power draw, but it was far less than the 430W rating on the PSU.

[G+_Travis Hershberger]

Sounds like the power supply is just not good, I don't suppose you have another you can test with?

 

Yeah, it really does take a lot for a desktop to pull over 400W from the wall anymore.  Mine here at work does, but it's a bit of a beast.  Phenom2 x6, 8GB DDR2, GdForce GTX 560Ti, 500GB SSD, 500GB HHD, Pci-E to USB3 card, HighPoint RAID card, and 9 1TB HHD.  Draws around 470 watts from the wall at boot when all those drives spin up at the same time.  Averages around 390 watts.

 

I really should replace all the old 1TB drives, they are getting into the 5th year of use.  Replacing 9 drives with 3-4 sounds like a good plan right now.

[G+_John Mink]

Well, I've noticed that if I unplug one of the HDD bays (doesn't matter which one, this case has 3 bays, each with 4HDDs) then it always recognizes everything.  So my theory is that the drives are all trying to draw on  the 5V rail rather than the 12V rail (maybe because of the hot-swap enclosures I'm using)?

 

And yes, there's certainly something to be said for pairing down on drives!

[G+_Eddie Foy]

Could use an amp clamp.  But make sure it will do DC (a lot on;y do DC)  Also make sure it will go down to 0.25 amps.

Some may have a min-max-average, where it will record the lowest, highest and then the average over time.

 

Its not a perm install, but just for testing.

[G+_Arcturus Lancaster]

If you can stagger spin up. That drive start draw can be heavy

[G+_John Mink]

Arcturus Lancaster how can I go about that?

[G+_Eddie Foy]

John Mink you could use time delay relays.  But might be going down the wrong road.  Get a PSU with enough amps on all the rails that you need.  And try to stay at or lower then 80% of rated capacity.  Don't just go by overall watts, but add up the amps on each voltage rail.

[G+_John Mink]

Eddie Foy are SATA devices even hot-swapable? Don't they need to be available immediately? Otherwise I could just put a large capacitor to use as a "jump-start"... But this only helps after I diagnose the problem!

 

Also... I didn't spec it out at all! It was just spare parts... I'm just trying to find a way to not go through this in the future :p

[G+_John Mink]

Also, apparently my response to your earlier comment didn't post...

 

But frankly I like the amp clamp better than some relay system or power cap.

[G+_Arcturus Lancaster]

Staggered spin up is often an option in raid controllers. Depends on options in tour hardware

[G+_John Mink]

Hrm, never heard of that.... Not thinking I'm going to implement it, but interesting to read up on