UPS Smoking, Leaking, Emitting Popcorn-like Sound -- Possible Source?

[Anonymous user]

Hi folks,

I have a BE650R that has served me well for a while (it's still under warranty) and just gave its first -- and evidently last -- sign of trouble this morning.

I had turned off, unplugged, and moved the unit a few days ago in order to throughly clean the area around my desk. The unit had been moved to the linoleum floor near the entrance to my apartment. There were no loads connected at all to it.

This morning, I awoke to the sound of an intermittent, weak-sounding beeping coming from the UPS. It beeped once every minute or two (unfortunately, I was a bit disoriented due to it being rather early in the morning and didn't have the presence of mind to time the intervals between the beeps). I thought that the battery had discharged over the last several days and the unit was signalling a low-battery condition and so I plugged it into the wall outlet and got back into bed. I did not push the power button -- it remained powered off but charging.

Several minutes later I awoke again, this time to a sound not unlike that of popcorn being popped. I immediately went to the UPS and noticed it sitting in a puddle of a thick, clear liquid and emitting smoke from its outlets. I immediately tripped the circuit breaker for that outlet, donned rubber gloves, and unplugged the UPS from the wall outlet. Upon opening the battery compartment, I was presented with more clear, thick liquid. I disconnected the battery, separated it from the UPS and, using paper towels, spent the next hour or so cleaning up the liquid.

Upon closer examination, there is a small hole in the plastic body of the unit on the "surge protection only" side (see picture). It appears as though the plastic body had melted. Due to the haste in which I reacted, I did not notice if the hole was the source of the liquid or if the liquid was emitted from the vents on the body.

As an experiment, I placed a small amount of baking soda in a sample of the liquid. It dissolved, but did not react in any other way. If the liquid were an acid, I assume that there would be some sort of reaction (e.g. bubbling). The battery does not appear to be bulged or otherwise damaged. Holding the battery at various angles and positions does not result in any liquids spilling from it. My multimeter reads the open-circuit voltage of the post-incident battery to be 12.98 volts, so the battery clearly has some electrolyte.

Any thoughts as to what could have caused this dramatic event? Any ideas of the source of the liquid, any special disposal considerations, and any thoughts on how harmful it may be? While I did wear gloves, I have no respiratory protection other than an open window and a fan.

I've contacted APC and they've agreed to replace the unit under warranty, but I'm curious as to the source of the problem.

I can provide additional photographs if requested.

Cheers!
-Pete

[Anonymous user]

Followup: The liquid does not appear to have originated in the UPS itself. As I've been moving many things around my desk recently, it's possible that I may have spilled something on or otherwise exposed the UPS to a liquid, though I have no recollection of any spill. Very strange.

Either way, many thanks to APC for their prompt handling of my phone call this morning.

If an administrator happens to read this thread, I'd appreciate it if they'd delete it. The option to delete a thread does not appear to be available to users.

[Erasmus_apc]

It looks like the battery may have "vented" or "gassed" and electrolytic fluid spilled out. This can happen when older/weaker batteries continue to be charged or if it gets hot, or if dirt or debris settle in around the battery. This liquid wouldn't necessarily have a high content ratio of acid (electrolytic fluid is typically a combination of hydrogen and oxygen, i.e. water) and therefore any baking soda reaction may be hardly noticeable. If the liquid got into the UPS' internal circuitry due to pressure build up, etc., who knows what could happen. The popping could have been a short caused by the liquid in the frame, or the popping could have been a fault that caused the buildup. It's hard to say, since this is a very rare occurrence and usually needs to be looked at in a test environment before deciding. The melting of the side of the UPS could have been caused by a part falling off the battery (I can't tell from the pictures) like a connector terminal, or just lots of heat during the battery venting.

[Erasmus_apc · Accepted solution]

Nevermind, I guess you answered the question! I can delete the topic if you really wish to, but it's not necessary and we can just close it.

[Anonymous user]

Erasmus,

Closing it would be ideal. Thanks.