My outboard motor (2023 Mercury FourStroke 300XL) is causing issues when running/charging and the 12v dual purpose starter battery is fully charged. I'm seeing wild voltage fluctuations from 13.x volts up to 20v. Folks online are saying this is due to the BMS on the battery rejecting the charging current from the voltage regulator/stator/charging circuit on the outboard motor.
Is there anything that can be done with this motor/battery combo? I'm planning on going to buy a replacement AGM unless there's something known that could be adjusted on the BMS easily.
