I stumbled on this thread when checking what other P4 threads I was missing out on. The voltage is very transient, and you also have to be careful to distinguish between your battery voltage and the measured voltage in the system during charging.
NB: all the following is dependent on root.
The
dumpsys batterystats
includes lines for "volt=???". If you extract all of these and convert the ms offsets to times, you will get graphs like the following
I can only assume the numbers should be divided by 10 to get to the mV You can find this graph at
Currently Running>Battery>Battery History Extras>AUTO-WIDTHx4>Graph of Explicitly Recorded Values [VALUE]>NONE - Direct Values Logged>Battery Volt [VOLT].VALUE
Also from the dumpsys, you can get the charging status (as well as battery power and with some calcs, the drain rate) which gives me the following for the same period as above
Pretty clear the measured "volts" jump up during charging. NB: I am using an old low wattage charger, not the fast charge.
The above graphs were generated using my app
TeMeFI, with some details on the above features in the
post1 and
post2. There are >100 other graphs from the app, including the discharge rate over time. Ands you can also extract the data frommwhiuch the graphs are based.