Topic: 24V 1kW+ Power Supply from Server PSUs

1kW chargers are coming!  FMA announced their cellpro powerlab 8 a  couple of months ago and now the Junsi iCharger range has a 1kW offering, the iCharger 3010B.  When flat out these chargers will allow you to charge 6 x 8S 5000mAh lipos in parallel at 1C but do present the obvious problem of where will you find a 24VDC 1kW DC PSU from?  At 12V input, each charger will only deliver around 500W so you really need a 24V PSU to get the best out of them.

There is a relatively cheap solution if you don't mind a bit of DIY and are willing to take the necessary precautions.   A number of switchmode server PSUs are easily had on eBay for around 20 quid each.  2 in series (with appropriate precautions taken), can easily deliver more than a kilowatt at 24V DC.  

I'm using a pair of HP ESP114A power supplies, which put out 55A on their 12V rail.  







I'm still sourcing a few parts for this "build", so expect it to take shape over the next week or so.

peevie, Thanks for sticking this up early, this could be a real option.

I will be watching this one very closely 

are you going to locate the 5v line as well so you can charge your phone and bits from it  (use a USB lead)

Gareth

Waiting with interest ....

This is the pinout to the rear.  



On the bottom row of the small pins, pin 2 from the left is the common, pin 5 is the switch line and pin 6 is enable.  Enable must be wired to common before the PSU will work.  When the switch line is not connected to common the PSU is in standby (green light flashes) and with the switch line connected to common the PSU powers up.  In other words if you want to use a switch connect it between Switch line and common, otherwise permanently wire both switch and enable to common.

Before I do any wiring I'm going to join the two PSUs and clad them so they're isolated from each other and from me.  In order to put the PSUs in series it's necessary to perform a ground lift on the 2nd PSU, so for safety reasons it needs to be insulated so you can't touch the metal case.  This is to cover the eventuality of an internal fault connecting the mains live to the case and as belt and braces I'm going to connect a neon indicator between the two cases, so in the event of that fault occurring there will be a clear warning.  

I'm using A3 sized sheets of 3mm black acrylic perspex to clad the power supplies and off cuts of this to sit between the cases to insulate them from each other.  3M VHB tape is used to stick the perspex.  You might be surprised at using "double sided sticky tape" but believe me this stuff is unbelievably strong.  They use it in construction to stick up lightweight partition walls and the pressure activated adhesive once stuck, stays stuck.  With experimentation I found the best way to cut the perspex was to score it then bend it so it breaks along the line.  

Some pics.

A bit of light dremmelling opens up the terminal shrouds and job no. 1 is to link the +12V from PSU 1 to the 0V of PSU2.  I'm using 2 links of 12AWG wire, I did try 10AWG but it's too big to fit in the terminal blades.



The perspex top is oversized so at the rear I have space to drill holes for some 4mm gold sockets.  A lite ply subframe fixes below the perspex to give some more "meat" for the glue to fix to.  Gorilla Glue does the job nicely here, tough enough to keep the sockets in place when subject to the force of banana plugs being inserted and removed.

Using the various tap offs available from the pair of PSUs I can get 5 different potentially useful voltages and I'm colour coding my 4mm sockets to differentiate them.  So I have 5V, 12V, 15.3V, 17V and 24V outputs brought up to the top surface.  In the corners there are a pair of SPST switches which will be used to control the standby on each PSU.  



Wiring the sockets up is actually not too hard as once tinned the wires will push into the blades to the rear of the PSU, with the blade acting as a clip.  A nice powerful soldering iron helps get a good solder joint between blade and wire.  



A neon indicator is positioned at the front of the case where it will be noticeable if it lights.  This is the "mains fault" indicator which is connected between the two cases, sensing the unlikely but possible fault condition where the ungrounded case of PSU2 is connected to mains live.  



Final view of the rear of the unit, you can see the wires from the neon emerging between the two cases and soldered onto each case.  The mains and power terminals are "potted" with hot glue covered by insulation tape, to prevent any shorts should something drop down the back.

So for a total expenditure of around £50 I have a bench power supply built on ultra reliable well regulated server PSUs which will supply any of the following:

+5V at 30A,
+12V at 55A,
2 x +15.3V at 45A,
+17V at 30A,
3x +24V at 55A.

And you can mix and match the above to a total power limit of 1740W.  You can't touch this for value for money, an equivalent commercial unit would cost several hundred pounds.  In fact I see someone's currently selling these PSUs for £10 each on eBay which is the cheapest I've ever seen them: [ebay]370364560304[/ebay] so you could probably put one of these together for less than a standard 20A 12V PSU bought from a model shop.

Very nice. 

Presumably the old days of having to load the 5v rail to achieve stable regulation on the 12v are gone ?

Absolutely.  These PSUs are a class act, the voltage measured by my iCharger on the 12V line is 12.01V.  Everything is very well regulated and protected, as you'd expect from a mass produced unit designed to be used with very expensive servers.  They are a bit noisy though!

Peevie, great stuff, thanks for posting that up   A couple of questions though.....

The small signal pins Common, Switch and Enable - there look to be four small pins for each function? Have you tied those together yourself or have you just wired one of each of the pins?

Also how did you wire up the Neon light?

And finally could you post a piccy of the back showing all the finished wiring in close up?

I'm going to order those PSU's from the link you gave and get one built this week. I was just about to order the Logic RC 600W charger (for £90 ) so this will be a significant saving  

Peevie, great stuff, thanks for posting that up  A couple of questions though.....

The small signal pins Common, Switch and Enable - there look to be four small pins for each function? Have you tied those together yourself or have you just wired one of each of the pins?

You mean a vertical row of 4 pins?  Ignore the rest, it's only the bottom row we are interested in.  What the rest of those pins do, who knows.  Some kind of status monitoring, fault signalling, etc.  In any case it's only the bottom row pins 2, 5 and 6 (counting from the left) that are needed.  I took what is hopefully a better pic, notice the enable pin on the far RHS is shorter than the others.

Also how did you wire up the Neon light?

It's simply soldered to the two cases.  Polarity doesn't matter.  If the ungrounded case has an internal fault making the case live, there will be 240V AC between the cases and the neon will light.  You must use a high power soldering iron to get the case hot enough that the solder flows onto it, no room here for dry joints.  I used a 100W iron.  Here's a closer view:

And finally could you post a piccy of the back showing all the finished wiring in close up?

I'm going to order those PSU's from the link you gave and get one built this week. I was just about to order the Logic RC 600W charger (for £90 ) so this will be a significant saving  

I'll post a few.  The views of the final wiring probably don't help too much as it's all potted in hot glue and covered with tape, so I've cropped my previous in-progress pics too.  The only thing missing from those is the mains and signal wiring.

I'd like to emphasise to anyone planning to duplicate this build, you need to be aware of the safety issues.  The second case is only connected to mains live and neutral, no earth, meaning there is the potential for a fault to develop which makes the metal case live.  Not trying to scare anyone, but you need to understand this.  Make sure it's not used where kids can get anywhere near it, make sure you insulate the case and do use a neon to cover this eventuality.  Bottom line is if an internal fault caused the case to become live and if someone touched it, it could prove to be fatal.  I'm happy to accept this risk because I understand it and can mitigate it, plus I'm the only person who will be using this PSU.

PS. I also have one of those logic RC 600W PSUs (soon to be for sale!).  It's rated to 40A 600W output.  Interesting if you open the case, written on the PCB is "12V 30A PSU"!  Go figure  


More pics:

That's superb, many thanks

Two more potentially silly questions though

Why is case 2 not earthed? And you said that 'In order to put the PSUs in series it's necessary to perform a ground lift on the 2nd PSU' - this is done simply by virtue of connecting them in series isn't it not by any modifications?

Just double checking before I go ahead and build them. I'm also happy with the safety implications

Most switchmode power supplies, including these server PSUs have their 0V DC output connected internally to the chassis, which is in turn connected to earth via the mains lead.  This means when you connect two in series you have to "ground lift" (not connect the earth) on the second power supply, otherwise there will be a short circuit created.  This is because if AC ground is connected to both units then when you connect the 12V from PSU1 to the 0V of PSU2 you effectively short circuit PSU1's output back to its own 0V via the earth connection, because  the 0V rail on PSU2 is connected to AC ground (which is also connected to PSU1 0V).  

There are only 2 ways around this.  Either break the connection between PSU2 0V and its chassis, or don't connect earth to the second PSU so the return path back to PSU1 0V is broken.  

There's a diagram which makes it clearer than I can explain in words here:  Using two power supplies for higher voltage/capacity chargers: safety issues - RC Groups in fact the whole thread is recommend reading for anyone considering a dual PSU conversion.  

Ps.. because of the link between 0V output and the case, there will be 12V DC difference between the two cases when connected in series.  This is why they must be insulated from each other and never allowed to touch.

Again thanks Peevie, all makes perfect sense

I'm in the office Weds (next week) and I think we have about 10 old IBM blade servers that include some BIG psu's (they also charge the backup batteries, that I have already robbed!), if the 12V output is in excess of 20Amps, I dont mind bringing some home, if they will help anyone on here? BUT you will have to collect them from me, as I aint going to post them.

Again, I'm not in the office till Weds AM, so I cant collect (if they are worth having) till then, and even then I can only carry 1 at a time, due to there size. The servers are only in the scrap pile as they have been recovered from other sites and we are moving towards more and more virtual servers, making these quite new servers redundant, and my company will not sell hardware, but does donate to staff.

That could be helpful to some folks Graham, the trick will be figuring out the pinout as it seems nigh on impossible to find documentation on these server PSUs.  I guess as they're a modular hotswap item, the manufacturer doesn't expect anyone to need to know which pins require shorting to switch on the output, etc.  I avoided this problem by using a PSU already "cracked" by some folks on RCG.  Always best to let others do the hard work!  

Without knowledge of the pinout there could be some trial and error in figuring it out, with the potential to damage the PSU if you connect the wrong pins together.  

Excellent stuff Peevie 

I'm just about to savage my old Mig welder which I've recently replaced to see if it contains anything useful 

These PSU's definitely look like the way forward when it doesn't 

Will any brand of DL585 192201-002 PSU have the same pinouts and spec?

Received mine today, so will solder them up this weekend

Will any brand of DL585 192201-002 PSU have the same pinouts and spec?

No, that's a different PSU and I can't vouch for it's specs or pinout.  Maybe it's the same, maybe different but my guess is as good as yours.

To be clear, the PSUs I've used are for the DL580 server and have part number 192147-002.  Equivalent units are the 192147-001 which do have the same pinout and spec.  Either unit can be branded as HP or Compaq.

Search keys for finding these PSUs on eBay are any of the below:

"192147-001"
"192147-002"
"ESP114"
"ESP114A"
"DL580 Power Supply"
"DL580 PSU"

Received mine today, so will solder them up this weekend

Cool.  I'm charging with mine at the moment.  Sucking 32A out at 24V    They really are stunning value for money considering the build quality.  I wonder what they cost brand new.

By the way, I have 4 spares from the job lot I bought.  If anyone wants to buy them I'd be after the £20 each I paid and I could bring them to Weston if you like, or collection from Slough.  I'm not keen on posting them, you may as well buy off eBay.

By the way, I know I mentioned it in the thread above, but just to reiterate, you must insulate the cases of the PSUs from each other.  The case of PSU2 will float at +12V DC compared to PSU1, so if the cases touch, PSU1 will be short circuited.

Thanks for the heads up Peevie,  and as you say, insulating these from each other and yourself is critical, its going to be built into a ventilated cupboard out of harms way but with the neon light mounted outside near my charger. I'm running a modified 400w PSU from an oil and gas instrument array, but its hardly enough to get the best out of the duo charger.

Since its unlikely any of us will be running these things at anywhere near the rated output, and for fairly short times, Has anyone experimented with running the fans from the 5v outputs to lessen the noise?

Finished, a real beast of a power supply.

Vent holes are on the bottom and l/h side with an IEC connector on the front with a few deans glued on the front panel, 1x 12v 2 x 24v, 1x 15v and 1 x 17v

Thx to you guys who figured out the pinouts. Works perfectly, a little bit noisy but bearable, the fan speed is controlled by the PSU so not worth tampering with IMO.

Sweet!

Mine is finished too, really pleased with it, went for 1x5v, 1x12v, 1x17v and 1x24v in the end. Will put some piccys up when I'm back home at the end of the week.

Also bought the new Logic RC 300w +300w twin charger to go with it so will post up my thoughts at the same time.

I was tempted to go for a couple of these http://hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=11340#

but the reviews so far have been mixed,  if they get their QC in check it would be a proper bargain.

Peevie,

thanks for posting this thread up - I'm delighted with mine and for less than £50 as well  All done, just the neon to solder on when i get some more soldering iron tips.



Shows it neatly tucked in the corner with the outputs plugs recessed into the bench for tidiness  Plenty of power to parallel charge packs too.

Great to see the results of some of the conversions people are doing, and I like the integrated solution there Andy.  Are the metal handle subframes isolated from each other, they seem close enough together to be touching?  Also, where did you get your parallel charge cables?  They look like the ones Progressive RC sell.

Don't worry, they are isolated! They have 2x sheets of 6mm Correx between them to seperate them which extends out the back by about 15mm to make doubly sure they never touch.

Well guessed on the cables, they are from Progressive RC.  I'm really impressed both by the cables and by the service which includes free postage worldwide! I've got another cable coming which I ordered today and it will mean I can charge 8 packs in one sitting

+1 on the comments on Progressive RC.  David is a star, very helpful if you ever have problems or questions and with free shipping the cost of the cables is actually quite reasonable.  I now have 3 sets, one for each iCharger!  Why charge sequentially when you can whack everything on charge simultaneously 

Bit the bullet and bought a pair of these from here:

PSU's

Reasonable price of £44 for both, so now gonna go hunting for some nice black sheeting (where'd you get yours Peevie?)

Will be going the 24v route, and paying careful attention to location and the kids...

Had trouble with your link, was it these: [ebay]310221248564[/ebay]?

I bought a couple of sheets of this 3mm perspex from eBay: [ebay]290439047030[/ebay] It's ok but will show any fingerprints or scratches.  One you get your PSUs you'll see what you're dealing with, you need something to provide an insulating spacer about 10mm wide between the units, then anything you like to clad the outside.

Neat looking setup maxpoly, I like the correx cover.  

I glued the psu's together with some west system + 3 x perspex sheet cuttings on each end, then insulated between the handles using thin plastic sheeting, the handles looked like plastic but turned out to be metal.  Got to order some of those multi balance leads too.

Edit: looking at those cables mentioned earlier on PRC I came across this bad boy, now winging its way to me! http://www.progressiverc.com/index.php?page=shop.product_details&flypage=flypage.tpl&product_id=76&category_id=1&option=com_virtuemart&Itemid=1

 

Nice choice xtreme! I have one enroute too but I'm guessing yours will arrive first.  The 3010B was my reason for upgrading my PSU.

aren't progressive rc in the states? if they are you might get stung for duty and handling fee as it's a high value item. Every thing i've ordered from the states has had duty added which made it more expensive. I am waiting to see pricing and availability from hong kong

Had trouble with your link, was it these: [ebay]310221248564[/ebay]?

I bought a couple of sheets of this 3mm perspex from eBay: [ebay]290439047030[/ebay] It's ok but will show any fingerprints or scratches.  One you get your PSUs you'll see what you're dealing with, you need something to provide an insulating spacer about 10mm wide between the units, then anything you like to clad the outside.

Yep, that's the ones.

Still stuck on charger choice. Was going to be Fusion Emperor Pro or Hyperion 0615i DUO V3, but the new iCharger looks interesting too

Junsi tells me there will be a UK dealer for the iCharger range within the next 2 weeks.  It's where mine is coming from.

Junsi tells me there will be a UK dealer for the iCharger range within the next 2 weeks.  It's where mine is coming from.

Interesting. But only single output, albeit a very powerful one. I like the idea of 2 for flexibility.

Any idea what the price is like, in the UK?

No idea on price, but the way dollar - pound conversion usually works on imported goods I'll guess at £199.99

aren't progressive rc in the states? if they are you might get stung for duty and handling fee as it's a high value item. Every thing i've ordered from the states has had duty added which made it more expensive. I am waiting to see pricing and availability from hong kong

Yeah they are, its also a much higher chance of getting stung by customs from the us of a, I was ordering leads from them anyway so more for handiness sake rather than saving the pennies, might as well spend some of them, rather than let the current high inflation swallow it all, losing hundreds each week anyway from darlings money printing games already, 

Peevie,

thanks for posting this thread up - I'm delighted with mine and for less than £50 as well  All done, just the neon to solder on when i get some more soldering iron tips.



Shows it neatly tucked in the corner with the outputs plugs recessed into the bench for tidiness  Plenty of power to parallel charge packs too.

Can I ask where you got your 4mm sockets? Only ones I can find in Maplin are only good for 6A, and I'm gonna be using way more than that.