Just FYI, some UPS units are "inverting" all the time. Even when on "grid". They run the inverter and just charge the battery at the same time.
I would suggest you test it on the UPS compared to plugged into a wall to be sure.
Just a gotcha I ran into one time a long time ago.
Good luck with it.
TomW
"Education consists mainly of what we have unlearned."--Mark Twain[ Parent ]
Mike "I thought I made a mistake but I was wrong"[ Parent ]
If the output is Really 80V, the lamp will be a lot less bright on UPS power than grid power.
I expect the UPS output is fine. G- [ Parent ]
Peter.[ Parent ]
Assuming 110 ac will have a peak of about 154v then the 50% figure would give an average of 77v.
Most cheap meters read mean but are scaled to show the value as rms of a sine wave.
Allowing for the form factor you should read somewhere just over 80v so that seems reasonable.
As others have said the simplest way is to compare light with a filament lamp against known 110rms.
Flux[ Parent ]
Some contributors have found the UPS has a button to disable the buzzer AFTER they had cut the cable to the beeper!
Regards, dom We only ever use the best fencing wire for our repairs! [ Parent ]