Salvaging an old UPS

Ages ago I was given an APC PowerStack 450 UPS that was apparently dead. Being an eternal optimist I decided to see if I could resurect it. In theory no mater how knackered the batteries it should function when the mains power is on but crucially if no batteries are inserted (or if the batteries are in fact so dead that they conduct no current) the device is a brick. My hope was that it had been in storage for so long that the batteries had sulphated to such a point that they no longer conducted.
First I got the multimeter out and checked what I could (the internal fuses etc.) and it all seemed OK but the battery seemed lifeless even after charging with an external charger.

Before commiting to new batteries I wanted to test the device so I found some 6V batteries (that wouldn’t physically fit) and jury rigged connections to the device – blimey it works!

So now to get some new batteries. These cost a fortune if you buy the APC branded ones and even OEM ones seem expensive for the size of battery. I worked out that the batteries in the Powerstack 450 (APC part RBC18) are infact two CSB GP672F2. I found these available from the main reseller for CSB in the UK, MDS, and bought two batteries for £23.98 – a considerable saving over the APC part.

I striped down the old battery packand reassembled a new one using the replacement batteries….

Well it works!
The first thing that I noticed is how much power it consumes – I did some simple testing of power consumption on my server previously and I’d left the power monitor plugged in. Without the UPS the server consumes about 72W but with the UPS inline the whole setup consumes 81.5W – I didn’t realize how much power a UPS would consume in it’s own right!

As an aside I’ve created an updated page about power consumption of components and systems here.

To control the server and allow for a gracefull shutdown in the event of a power failure I decided to install the apcupsd (originally I tried NUT – network UPS tools – whoa way too complicated). I found the correct wiring for making up a serial cable to connect the UPS to the server.


INSTALL apcupsd

#yum install apcupsd apcupsd-cgi

That just seems to work…

Then I set up apcups by simply following the apcupsd documentation.

GOTCHA - problem with Xen stealing the serial port! Work around from here.

Now it seems to work and the status page is here...


  1. Alejandro Said,

    July 31, 2014 @ 5:05 am



  2. virgil Said,

    August 22, 2014 @ 8:55 pm


    tnx for info!…

  3. Elmer Said,

    August 22, 2014 @ 11:34 pm


    спс за инфу….

  4. don Said,

    August 23, 2014 @ 3:39 am


    good info!…

  5. curtis Said,

    August 26, 2014 @ 6:52 pm