The battery on that circuit looks very much like a backup battery we have connected to our house alarm.

We moved in to the house in 2003 and that battery died this year, so I would imagine that it is already or will very soon die. That said, if it's a backup battery and the electricity supply is stable then it may not make any difference.

▲

js2 an hour ago | parent [-]

It's a standard sealed lead acid battery:

https://www.rapidonline.com/yuasa-yuvolt-yucel-y1-2-6-valve-...

https://static.rapidonline.com/pdf/18-5207_v2.pdf

Design spec is up to 5 years. The one in the photo looks like it may have a date written in Sharpie on the side. I don't think it's 25 years old though. The "090323" on top could be DDMMYY indicating a battery from 2023.

	▲	compiler-guy 27 minutes ago \| parent [-]
		I agree with the 2023 decode there, but there is still a bit of a puzzle: If someone knew to replace the battery just three years ago, I would expect they also would have enough knowledge to set the clock itself. Or at least explain what was going on. Maybe this person isn't connected with the building anymore. But I would expect the new owners would be able to contact the old owners for help on this instead of sending a generalized call for help.