Had same problem couple years back. Changed batteries and with ulterra was running out of power in 5 hours. Now keep in mind this was pulling jigs and three big hinys in boat in windy conditions. Did on older batteries as well as new ones. I now run four batteries with 24 volt switching over at the plug. Have been running this set up for five years with no issues and lucky to have had enough space for the batteries. When this motor has to be replaced I will be going to a 36 volt system. Hope that doesn't happen for many more years due to the cost of trolling motors