Saturday 12 September 2009

UPS Battery Life = Monitor Or Possible Problems

One of our own UPS units, an APC SUA1500RM2U threw a battery alarm code not too long ago. We received the replacement battery set this week.

This is what we found when we eventually pried the existing battery set out of the unit:



Note the bloating in the battery housings. The battery without the label was the one that caused the most grief when prying the tray out of the APC UPS.

Some of the terminals on the batteries themselves were also showing some signs of frosting along with leakage.

The APC is hot swap capable, so we were able to swap out the batteries while the servers were still up and running. This particular unit is about 3 years old.

Ironically, while working in the server closet at a client’s site not too long ago, one of their SUA1500RM2U units threw a battery code as well.

So, today we will be heading down there to swap out both battery sets as they have two of the UPSs and both are somewhere around the same age of 3-4 years old.

Even with the UPS self-tests running every two weeks, the above battery condition did not show itself until something inside one of the batteries collapsed enough to cause a ground condition between the plates. Depending on the failure method, things could have been a lot worse when the batteries failed.

We will take to visually inspecting the batteries in these units on a yearly basis now.

We have seen the results of a spontaneous breakdown of a UPS’s internal components . . . along with the panicked phone calls about the noise and smoke that brings if it happens during business hours.

Fortunately none of the SUA1500RM2U units we have out there have ever done that. The units that we have seen combust were smaller pedestal style 350-1200VA units. We now tend to recycle them after 2-3 years instead of putting in a new battery.

Philip Elder
Microsoft Small Business Specialists
Co-Author: SBS 2008 Blueprint Book

*All Mac on SBS posts will not be written on a Mac until we replace our now missing iMac! (previous blog post)

Windows Live Writer


stryqx said...

It gets real ugly when the batteries explode, taking out the circuitry along with it.

Combine this with an enclosed cabinet in a server room with return air and no exhaust and it gets real ugly.

Hence the recommendation to have UPSes outside the rack and preferably in another room, with a separate circuit to the rack able to be plugged into either the UPS or an allocated socket on another appropriately sized circuit.

The pluggable circuit also works great in extended outage scenarios as you can easily connect a pure sine wave inverter generator to maintain power during the extended outage, be it utility related of UPS maintenance related. Of course you need the ventilation for the generator and the ability to refuel it safely.

stryqx said...

Oh and it's really annoying when the batteries bulge like that, given that most battery trays already fit snugly into their mounts when the batteries are in their optimal condition. Bulging is not a rare event and it would be nice to see UPS manufacturers provide some leeway for this type of bulge to enable easier extraction.

Philip Elder Cluster MVP said...


Ideally yes to all of your points! :)

But, many of our clients have server closets that were essentially afterthoughts ... with very little thought beyond that.

And, yes, it would be nice to have just a little more wiggle room to pry the batteries out. That was quite the struggle.



Josh Gay said...

We've been bit by this, and try to keep more careful watch on them, but sometimes they slip through the cracks. Was trying to figure out why the server was rebooting early on Monday's at one site, until we figured out the batteries were low, and the Generator was set to exercise at 5am on Mondays.

Philip Elder Cluster MVP said...


I finally managed to get to our client's site where the battery light had come on while I was there as mentioned in this post.

The second UPS's light was now on too. Fortunately I had the sense to order and invoice battery sets for both UPSs since I figured they were both around the same age.

When I pulled, or tried to pull, the first battery set I could not do it. I had to grab the tray and brace my feet on the base of the rack enclosure to get the leverage I needed to slowly work the tray out.

The top of the SUA1500RM2U literally had a 1/4" bow in it once I got them out. I was concerned that the plates might cause a spontaneous combustable situation. Fortnately they did not.

But man, was that first dead and bloated (STP anyone? ;) ) battery pack hot when it came out. Initially I could not even touch it.

The second one came out with relative ease as the packs were not too bloated at all.

Thanks for the comments guys!


Josh gay said...

Picked up a couple of the 750 version of this UPS at surplus sale a month or so ago, hadn't looked inside yet, was greeted by 2 batteries that i'm not sure will be coming out the front of the unit, (will send you a picture once I take one, took the top off the unit to to see the mess), scary for a unit manufactured in 2006, I begin to wonder what changed in those v/s the previous models that didn't seem to do that so bad.