I have a 24v setup with everstart 750mca 27dc. Next month they'll be a year old. The past two trips they lasted about 3 hours. Had the batteries tested at wal mart and auto zone, both said they were good and had a little over 12 volts. The water/acid level does seem a little low as I can hear it sloshing around. Could this be an issue with my trolling motor armature? Trolling motor is a motorguide tour 75lb, probably a 2007 model.
Anyone have recommendations on trouble shooting before I buy new batteries?

Thanks,
Mike

Is the water/acid level above the lead panels? As long as they are covered and you don't have a bad cell (which is possible) and may not show up when tested you should be good to go. Had this problem with a Napa battery until they exchanged it and problem went away. I also replaced the 27 with a 31 and that made a huge difference, run all day and power to spare.

Quick easy check...pull the prop and check the arbor for fishing line wrapped up causing excessive amperage. Could also check the brushes. For a motor that old, with typical usage, they are probably due for a change. Finally, check all connections for corrosion, clean as needed.

I've had those same symptoms twice over the last 3 years and both times it turned out to be a dead cell. The battery tested OK for voltage but a hydrometer test indicated a dead cell. Charge the batteries and check each cell with a hydrometer. Hydrometers are cheap at Walmart ($10-$15).