Hi I am designing a portable battery powered device using 2S 18650 batteries and have chosen the BQ25306 as the charger. I have looked through the forum and read a few interesting problems of which I have included in my design but I have a major problem when it comes to the batteries being installed incorrectly.
If the batteries are installed reversed what will the charger do?
I have read your article SLVA139 showing how to add reverse battery protection. Will this work correctly for the charger even when the batteries are installed correctly but are discharged to 0 volts?
I am also assuming that for this to work correctly the FET source must be on the charger side and not the battery side as there would be a current path through the FET diode when the batteries were reversed.
I have also included a low battery shut off circuit but this will only disconnect the load and not the battery charger circuit.