I have a minn kota battery charger and it reads that the trolling motor battery is fully charged but, when I get on the water and check the level it starts off at around 50 percent. Could the reason for this be a bad cell in the battery? Should I just get a new battery or could it be the charger?

Any help or advice would be appreciated. The batteries are less than 6 months old.

It might be the charger.......I'm on my 2nd Minn Kota and on my way to a third charger.....lost a bank on mine.

Why not check the battery with a digital voltmeter and check each cell with a hydrometer? The hydrometer is THE best way to know the status of each cell. Check the battery while charging to see if you get 14+ volts. Check charger info to learn the exact voltage levels to expect.

What exactly is telling you that the battery is at 50%? Judging percentage of charge (other than with a hydrometer) itself can be problematic. Whatever is measuring charge level could be defective as well.

A small inexpensive hydrometer can be had for ~$3.50. My good one was all of $10 online.