I have the wireless meter ( two parts transmitter and display-controller , display uses 5volt USB, monitor transmitter mounts at battery uses 12v ) that shows capacity percent, capacity amphrs , voltage .amps plus or minus, charging or discharging AkA load amps, the meter stops adding amphrs once it gets back the counted discharge, BUT it keeps on displaying the charging amps going in, when It gets down to less than 1 amp charge rate I know it's full, even if that takes 2-more hours of charging after the amp hood counter stopped
That is the true measure of fully charged when using sealed agm batteries
So IF I stop the charging when it is at 4 amps charge rate, I know I'm not full, even though the capacity number says I am !
A full days charging to the amps drop off point sets everything at the correct start point,
I can reset/change the battery capacity if/when the capacity changes with age and use