I have an 06 300 HPDI, that has about 30 hours on it. This past weekend while fishing a tourney after running my livewells etc all day, the starting battery was dead..... I do not have a voltmeter on the boat, is there any other way I can tell if the motor is charging the battery ?

I came home and put the charger on the starting battery and it charged up fully within about 8 hours. ( i had not charged the starting battery in about 2 months, although I use the boat most every weekend) So I am assuming the battery is okay !