Battery has toasted terminal smell, that unique metallic tang of “I’m shot”.
Terminals on device itself are fine, no scorching pitting or scoring.
Terminals on battery look fine.
So odor is from it giving up the ghost.
APC brc123, has a flat wafer with some electronic crud on it sandwiched between two battery blocks.
Electronic crud on battery sandwich is probably tode.
*sigh*
I once watched someone fly out of their clothing due to close proximity to a sudden fire.
She didn’t believe me that she was fine.
Insisted on having her gear checked for melting and scorching first.
*shrugs*
Stepping away without immediate ejection from what one is wearing would have sufficed.
I performed an autopsy on our unit and determined the failure was from an external cause.
My guess was that a neutral wire had lifted in a main circuit going to the unit, causing a return path from the building load, or part of it, to go through to the chassis of the APC. Our building is not old so I called the company who wired it to come and inspect, and they reported nothing wrong.
I was not convinced and sure enough, our replacement APC did the exact same thing a couple months later.
Again I had the electricians come out and eventually they found what I told them to find, and they fixed it and we haven't had any more trouble.
Yet.
Too bad the company that did the plumbing in our building is defunct. Or maybe its a good thing. On a number of occasions I have come to the store to discover many gallons of water laying around where it didn't belong (rolling out from under the front door, for example), and just last Friday as we were closing up, a major burst happened which would have been more major if it happened just five minutes later.
Life in boomtown, it is what you get, and proof that the unemployment rate can be TOO LOW in some places and times.