battery accuracy reading and battery longevity is fully dependable on the phone software and the efficiency of the smartphone chip.

a 3700mah smartphone battery can go far better in battery autonomy/longevity than a 4000mah or 5000 mah battery smartphone in terms of hours of usage.

reset the settings of your smartphone

clean the usb port with a piece of cotton moisted with white alcohol

if the battery is removeable clean the battery connector with a cotton moisted white alcohol as well as the connector pins of the smartphone

let it charge

please note that when the battery connector are wiped and put in the phone the battery reading will change.

do it if your phone is stuck on a specific battery percentage for a long time during charging.

mine stucked on 83%

when i cleaned the battery and phone connector pins the reading changed to 97%.