one of the downsides of modern electronics is digital meters without any damping.
I have tossed most of mine & gone back to an analog one when working on the bike.
I bought a very expensive one only to find that I have to preset the range to 00.00 V every time tried to take a reading otherwise it read each contact running over the comutator so it went 0 to 9 V and back a squilion times a second then as the voltage was getting low when the brushes cross the seperator it would automatically switch to mV and became unreadable.
The 50 year old analog meter read a flucuating 6.9 to 7.2 volts.