I would normally leave a TNMOC post to @EdS or another of the British cohort, but I really enjoyed this article and no one has shared it yet:
I’m not sure why I like it so much; perhaps because it seems like something I could do if push came to shove.
I find it interesting that I had always thought of UPS functionality as something that was either a) relatively modern, or b) limited to high availability applications such as military and safety critical settings, but I have increasingly learned that it has been a part of computing essentially since the beginning. The PDP-11 UNIBUS even has dedicated signals for battery backup!