Repurposing Server Power Supplies

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Eric
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Repurposing Server Power Supplies

Postby Eric » Wed Sep 26, 2012 9:12 pm

When I dug through my box of power supplies, it turns out my biggest 12V supply on hand (other than what's in my computers) is rated at 10 amps. That isn't going to cut it when I add the heat bed. Sure, I could buy another higher-powered PC supply, but I've found an even better source at a cheaper price.

There's a glut of retired data-center servers on the recycle market. Almost every one has two redundant 12V power supplies ranging from 25 to 100 amp capacities, depending on server model. Server supplies are not like PC supplies...they have lots of 12V capacity and very little, if any, capacity in other voltages. They also tend to be specific to a server model, so once that model is obsolete, there is little resale market, even as spares. That leaves great deals for the hobbyists. The RC people like them for custom lipo charging stations at 12V or 24V(using two). Radio amateurs use them to run their 12V equipment. And they make great bench or serious project supplies. And what could be more serious than your CNC machine?

These supplies were designed for commercial data-centers where they've likely been run 24/7 for many years. As redundant supplies, they've spent most of their life carrying half their rated load. They're old, maybe dusty, but they still work. The catch? They have specialized connectors and no manual. You have to be comfortable enough to figure out how to wire them up and what pins to connect to turn them on. Here's one resource to get you started: http://www.rcgroups.com/forums/showthread.php?t=1292514.

The price? Depends on how hard you hunt and what you're looking for. ~$15 including shipping for a 40A 12V supply seems fairly easy to find on ebay.

The ebay deal I just ordered is: a pair of DPS-500CB's for $4.99+$12 shipping, so $17 for TWO 41A 12V supplies. I like the idea of having a spare for the next project.
I already found good instructions on how to use this particular supply: http://krcm.mywebnow.org/index.php?action=dlattach;topic=330.0;attach=1502(opens a pdf file)

(edited to update broken link to pdf)
Last edited by Eric on Mon Mar 23, 2015 6:14 pm, edited 1 time in total.

Eric
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Re: Repurposing Server Power Supplies

Postby Eric » Wed Oct 03, 2012 2:58 pm

I'm extremely pleased with my DPS-500CB purchase. Here's the listing I used if anyone else wants to grab a couple:
http://www.ebay.com/itm/Lot-of-2-Dell-Poweredge-2650-Power-Supply-DPS-500CB-J1540-/370648604418?pt=US_Server_Power_Supplies&hash=item564c60df02

Physical dimensions are 2.5"x3"x14" including the rear connector. Rear intake fan is reasonably quiet -- I may tape a foam filter over it to keep the dust out. The idiot lights on the front are power-on (control pins enabled), fault, and input power cord plugged in. Takes a standard computer cord, not included. Dataplate says +5VSB 2A, +12V 41A. I haven't bothered to identify which pin(s) provide the 5V, since I don't need it. 12V and GND are the large spades on both sides of the connector -- I'll be soldering wire to those although you could use alligator clips for testing. I wirewrapped rather than soldered the control pins, with the thought that I may add a power switch later. For now, I'll pull the power cord or use the switch on the power strip to turn it off.

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xojins
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Re: Repurposing Server Power Supplies

Postby xojins » Wed Oct 03, 2012 4:13 pm

wow.. thanks for the link! Im in for 2. 12v 41A rail is nice.

now i need to build a cnc and a second 3d printer :)

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Re: Repurposing Server Power Supplies

Postby Eric » Wed Oct 03, 2012 7:33 pm

Should you have a need for 24V, those supplies can be put in series, but only after safety modifications to isolate the DC GND from the case.

If you need 48V, that's another voltage that can be found in surplus equipment, but not as cheaply as 12V stuff. The HP aa22680 (48V, 13.5A) is an example of that: http://www.ebay.com/sch/i.html?_from=R40&_nkw=aa22680.

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Re: Repurposing Server Power Supplies

Postby Eric » Sat Nov 10, 2012 4:57 pm

Thought I'd touch back and show what I did to interface these power supplies. I opened up one unit and confirmed that the heavy connector lugs come off the same +12 and GND buses. It was also easy to identify the top row of pins as being +5,+5,+5,GND,GND,GND. I also blew out dust, but there was so little I didn't open the other unit.

First I cut up a strip of 8 screw terminals with spade connections into blocks of 2 screws. They're rated at 20A, so if I ever need the full capacity, I'll just have to use both sets of terminals. A little bending of one spade and trimming an opening in the connector let me solder them in place. It took a good minute per lug to heat the mass up enough for soldering to be possible.

Then I undid the wirewrapping I did for testing and made little plug-in modules on a piece of protoboard. I included a switch so the 12V bus can be disabled without unplugging the unit.

First unit. Switch enables 12V bus only, which includes the fan. The LED is on 5V bus. I added a couple pins for easy access to the 5V.
Image

First unit. Plug-in board removed for a better view. When cutting up the terminal strip, I made sure to preserve side insulators on the +12V, which is on the right side.
Image

Second unit. I went minimalist on the plug-in board, and squeezed the switch between the terminals. No LED, no 5V connector.
Image

Second unit, with plug-in board removed. While there's only three pins I needed, I had to add more for physical stability. The wires go to the ramps connector. This is the unit I'm using for the printer.
Image

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Re: Repurposing Server Power Supplies

Postby Eric » Thu Jun 12, 2014 2:43 am

Did a review of what's out there today. The DPS-500CB is still available, but not as plentiful as I remember. I found a two for $19.99 listing on ebay with free shipping, so it's still a good option.

If you are looking at other models, see if you can find instructions on how to power them up before you buy them. You don't want something you have to figure out yourself, unless you're into that sort of thing.

Also, some otherwise-excellent server supplies do not have integrated fans as they were designed to make use of the server chassis airflow. If you run them standalone, they'll overheat in about 10 minutes. Avoid those unless you are willing to provide a cooling solution.

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Re: Repurposing Server Power Supplies

Postby JohnStack » Thu Jun 12, 2014 10:53 am

I have a friend who is a bulk recycler/dismantler of these types of servers. Let me do some checking today. I've been meaning to do this anyway.
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bvandiepenbos
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Re: Repurposing Server Power Supplies

Postby bvandiepenbos » Fri Jun 13, 2014 12:42 pm

Great find.
Thanks for sharing.
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bvandiepenbos
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Re: Repurposing Server Power Supplies

Postby bvandiepenbos » Fri Jun 13, 2014 2:53 pm

just bought 2 for 19.99 with free shipping one ebay. http://www.ebay.com/itm/131204568636

THEN I find what appears to be the same thing for $3.99 !
https://www.andovercg.com/store/Servers ... MgodUmMAeg

grrrr, oh well 10 bucks each still is a steal.
~*Brian V.

RostockMAX v2 (Stock)
MAX METAL "ShortyMAX"
MAX METAL Rostock MAX Printer Frame
NEMESIS Air Delta v1 & v2 -Aluminum delta printers
Rostock MAX "KITT" - Tri-Force Frame
GRABER i3 "Slim"

Eric
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Re: Repurposing Server Power Supplies

Postby Eric » Fri Jun 13, 2014 5:06 pm

bvandiepenbos wrote:just bought 2 for 19.99 with free shipping one ebay. http://www.ebay.com/itm/131204568636

THEN I find what appears to be the same thing for $3.99 !
https://www.andovercg.com/store/Servers ... MgodUmMAeg

grrrr, oh well 10 bucks each still is a steal.


Free shipping isn't actually free, it's just included in the price. When shipping isn't included, you need to add it before comparing prices.
In AndoverCG's case, two of them at $3.99 plus $16.72 shipping = $24.70 or $12.35 each. Not awful, but you did better with ebay.
But if you wanted ten for some reason, it becomes reasonable: $39.90 + $30.78 = $70.68 or $7.07 each.
(note, those shipping prices are to my address, which is a lot closer to San Francisco than you are...your shipping prices are probably worse.)


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