HP PS-5501-1c Server PSU - converting to 13.8vDC

[VK4CZ]

I've just acquired two HP PS-5501-1c server PSUs and have been thinking of using them to power the 13.8vDC requirements in the shack.

A quick search of the Internet and a few topics found about using these as 12vDC chargers... but little else.

Has anyone tried to modify the output voltage of these up to 13.8vDC?

If so, can you please share your approach?




Scott
VK4CZ

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[VK4CZ]

Some times the best approach is to just try it for yourself!!

Searched the interweb thingy and found the pin outs for the HP PS-5501-1c and went about enabling the SMPSU.



By connecting A5 to A6, A11 to A12, B6 to B5 and B22 to B23, and then B11 (PS on) to ground [I found that all the REM sense pads needed to be connected to enable it, not just the 12vDC rail] the PSU is enabled and delivered 12vDC.

Taking the covers off, I found two small pots on the edge of the cct board. Turning the one on the right adjusted the 12vDC rails.... and easily achieved 13.8VDC. OVP kicked in at 14.4vDC and shut the PSU down.



Tested the PSU using two 110W driving lights as loads. At 110W load, just 0.04vDC drop, and at 220W a total 0.06vDC drop.

Have to say I'm happy with this (given the complete server only cost $5 at a computer company junk sale last week - they had two more too which I may have to just go and get). Now to find one of the spare project cases in the shed and finish building up a 13.8vDC 50AMP SMPSU!

[VK2ZRH]

A great score, Scott - in the true amateur tradition

[ Thinks: have to keep my eyes-&-ears peeled for this stuff ].

[VK5PJ]

Scott,
there are a few locals in the Barossa area that are into SMPS (Ian, VK5AIC loves them) and have seen a few HP server power supply conversions (Sam, VK5ASK). From memory there is quite a bit of interest in the model racing car forums about these, they use them for light weight chargers for some of the exotic batteries used in Radio Control car racing. I will see if I can find some links to pages for others who might be interested.

Ian, vk5aic has a solid state dummy load he uses to demonstrate their output capacity and the results are impressive.

[VK2AAH]

How have they found them noise wise? Putting them in an external case should easily shield them but I'm curious if anyone has tested them without a case.

Cheers

Richard
VK2AAH

[VK4CZ]

VK5PJ said:
From memory there is quite a bit of interest in the model racing car forums about these, they use them for light weight chargers for some of the exotic batteries used in Radio Control car racing

Peter - that's where I found the pin out data... they have some amazing 'battery chargers' using ex-computer server SMPS.

VK2AAH said:
How have they found them noise wise? Putting them in an external case should easily shield them but I'm curious if anyone has tested them without a case.

Richard - am going to do that test soon.... and will advise.

I found a case in the shed (ex-UPS case) perfect for the project, which I've cleaned up, sanded and given the first coat of matt black Killrust.... and ordered a coloured LCD voltage & amp meter (0-40vDC & 0-50AMP) of evilBay this afternoon (all of $14.95 with free shipping). So if all works out OK, I'll have a 50AMP SMPS for the shack costing me less than AUD$25 (including the Killrust spray can).

Will post pics once this project advances!