Power Supply's HP DPS-600PB B 575W question

fran11784

Goblin 380 Supporter
Tony

Just watched your video on creating a 24v power supply using two of these server power supply's. Here's my question: I have one of these that has been built to supply 13 volts and one I just got stock. Id like to use them together. Do you think one at 12v and one at 13v in series can work? Say 25+ volts? My charger can handle up to 28 volts DC. Of course after doing the ground mod. Thanks for any suggestion's.
 

murankar

Staff member
Personally I would mod it back to 12v then use it. I have read a while ago that adjusting the output on those can cause them to be unstable at high amperages. I wanted to do that to mine but settled on leaving them stock. Could they work together, would say yes. I have heard of people dropping the output of one to get a max of 34 volts on a set of three.

What Charger are you using with it?
 

Smoggie

Well-Known Member
It would work in in theory, but I have used these exact same power supplies and I can confirm muranker's concerns to be true. If you adjust the supply to deliver higher voltage it becomes unstable at high outputs. I originally set both of mine to 13v and while it worked ok at low load, at higher current the supplies trip out. Far better to run then at their default voltage.
 

fran11784

Goblin 380 Supporter
I'm using a Hyperion 720 duo. To be honest the guy who built this 13v unit did a terrific job making it look factory. I think I'll just pick up another psu and leave the other alone. There cheep enough.
T
 

Smoggie

Well-Known Member
All you need to do to adjust voltage is turn a trimmer pot. I cant recall if you have to open the case to do so, most likely you do, but that's not a big deal it's just a few screws.

You are going to have to open up a case on one of them to isolate the internal earth anyway.
 

fran11784

Goblin 380 Supporter
I don't have a problem opening one of them. Here's a picture of the one I bought built. I hate to mess with it.

photo (82).jpg
 

murankar

Staff member
I am not sure how that charger will handle a psu failure. I know that powerlab chargers can handle a psu failure, where as icharger can not. So keep that in mind when building these things. Also coolice makes a circuit that will protect the icharger. It will probably work for others too.
 

Smoggie

Well-Known Member
I don't have a problem opening one of them. Here's a picture of the one I bought built. I hate to mess with it.

That's a very neat output connector that the guy who modified the PSU has fitted. To open the case you wouldn't need to disturb that connector, but you would have to remove the outer heatshrink covering (no big deal)
 

fran11784

Goblin 380 Supporter
cool ice
I've been chatting with them about the circuit. He said Hyperion doesn't suffer like the I-charger but still would work to protect it.
T
 

murankar

Staff member
Again just another thing to be aware of. That's good then, my pl6 stops all charging as soon as a voltage like that happens.
 

Chadm

New Member
Hey! I just watched your very interesting YouTube walktrough on the 1000W 24V DC power supply... I have two queries off the back of that... I am looking for a 12V DC power supply, not 24V.

Q1) If I aim for 500W output power using just one PSU, do I still need to do the earth mod as shown in the video?
Q2) If I want 1000W @ 12V, how does the wiring differ? I guess it's parallel rather than serial, but which terminals connect to where? Is it positive to positive and negative to negative?

I guess then if one PSU goes bad your output current just drops by 50%? Anything else to be aware of? Another video walkthrough would be nice, assuming there isn't one already...? :)

Thanks.
 

Tony

Staff member
You are correct, you would only use one PSU and you would NOT have to remove the DC ground doing it this way. If you are wanting 1000w at 12v, then you just run them in parallel but I have not tested this and have not researched this to see what would happen if power fails on one. You would be looking at reverse voltage going into the dead PSU and like I said, I'm not sure what that would cause.

But in all honesty, if you are just looking to run 12v, there really is no need to run 1000w. Most chargers that say they are 1000w are done at over 24v. These PSU's will put out 575w by themselves. and that is more than enough power for most setups if not all.
 

Chadm

New Member
Thanks Tony. Yes - someone in work said about reverse voltage and that it could potentially melt internal wiring or worst-case catch fire. I guess some kind of fail-safe would be needed to prevent that. Part of me wants to do it under controlled conditions to see what would happen, but I'll be honest - I can't really be bothered.

While browsing the forum I stumbled across Slobberdog's 'A new power supply' thread regarding his DPS 1200 FBA power supply. Looking at that, I guess rather than two 575's it would be simpler to just use one 1200W... Thus removing the potential for one to fail. I have stacks of disused HP servers in work, so hopefully at least one has one of those PSU's fitted.

My application is slightly different to most on here... I'm not using it to charge batteries... I'm looking to use a 12V DC car amplifier in a mock home AV setup, powered via the mains. Current draw will vary constantly, depending on the load going through to the speakers, but on a low bass note it will be a pretty heavy draw, hence the pursuit of a high wattage PSU. I figure that as long as the peak current draw doesn't exceed the max output of the amp, it should cope fine with the fluctuations, but we will see. I have lots of spare audio equipment lying around not doing anything, so I figured I will have a play and see what I can create. Thanks for your help.

- - - Updated - - -

I figure that as long as the peak current draw doesn't exceed the max output of the amp, it should cope fine with the fluctuations, but we will see.

That should be, "as long as the peak current draw doesn't exceed the max output of the PSU"
 

Tony

Staff member
I see, in that case, I would definitely get a single 1000w+ PSU to do this job. However, I would put at least a 2 farad cap between the two for when it needs instant power. By using a cap, you will reduce the chances of it burning up the PSU or blowing an inline fuse. It's just another safety factor to keep from killing that PSU.

When you get this done, I want pictures and video lol.
 

Chadm

New Member
That's an excellent idea. I have one in my car but I didn't think about putting a cap on this setup. I'll get hold of a cheap one and let you know how it goes. Thanks!
 

Smoggie

Well-Known Member
When I first built my dual DPS 600PB supply I added a switch in a similar way. It worked as advertised, but I ended up removing it though because I found it a bit pointless. It was easier and safer to have the switch on the AC input side, and you already have such a switch on the wall socket:biggrin1:
If the wall socket is not easy to access you can get switched AC power leads for buttons and save all the hassle. I also figured it was safer to have the PSU fully isolated with an AC switch when it was not in use, rather than left 'live' on the input side.

I notice on that page he shows how to do voltage adjustment. From my experience I'd advise not to do that. While it does work and you can trim up the voltage to a slightly higher value, the PSU becomes unstable and trips when operated near it's maximum power. Better just leave it at default voltage.
 
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Smoggie,
Better to just solder all 4 together and just use the wall socket switch? Was only going to use the switch as temporary on/off while at the field. Not switched on at home while not in use... which probably answers the why bother question
 

Tony

Staff member
I'm with steve on this one. I do not have a switch on my dual setup, I just have the AC lines run together into a single plug, then I just plug and unplug it from the wall. If I was going to use a switch, I would use a 15a or 20a switch mounted in my case on the hot (black in USA) wire to cut the power. As long as your house is wired correctly, the white and green wire should both go to ground unless we are talking about 220, but we are not lol.
 
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