Data loggers

[Ren]

I'm not sure if it will record over an extended period of time, but TI's CBL (Calculator Based Laboratory) would monitor temperature and voltage using a TI-83.
I bought a CBL a couple of decades ago, but haven't used it.
Both the CBL and its successor CBL2 are available on TAS.
I also bought a $40? temperature logger on Amazon a few years ago. (2021)
I was concerned about a refrigerator/freezer maintaining temperature.
It was an ECOWITT DS102 USB Temperature and Humidity Logger (no longer available?)
I placed it into said appliance for a day or two and then its PC software charted the readings.
It did not need to be plugged into the PC while logging.

This past year our Generac whole house generator would start at random times, and I
was concerned if it was responding to glitches in the utility feed or just not working right.
(a firmware update eventually fixed the problem)
I was thinking about buying/renting a logger to see if it was the utility, but didn't pursue getting one because of the cost.