This could be a battery issue, checking the batteries may require a high rate discharge check to determine if there is a faulty cell. Maintaining them is most important i.e. Water Levels, clean and tight terminals, tight nuts on battery leads, no loose wires, no damaged wires, battery charger is not working  properly, ensure your machine is fully charged before leaving the workshop. Could be that the operator is overlapping excessively, rolling too far off the greens surface up and down the sides of the greens or not switching off the ignition when towing the roller between greens.