Went out several days ago and noticed my trolling motor seemed weak from the start........ by mid day I had very little TM power left...... when I got home instead of plugging up my onboard charger I put a charger that shows volts / charge percentage etc etc....... one battery had about 50% charge left...... the other was single digit, virtually completely dead...... I'm guessing the one that was dead is likely my problem...... dead battery seemed to charged fast and is showing over 13 volts....... the other battery seemed to charge at normal rate and is also showing 13 volts......... so my thought is I have a bad battery ........ BUT........ is there anything I could be overlooking?