I took an old aerator and cut the wires going to the battery holders, spliced a USB cable to them and using a milwaukee battery power supply that put out 3volts DC, ran the aerator all day long. Being double what the batteries put out, the motor ran very fast, and very loud. I was ready to throw it overboard, but didn't. I now have a new battery operated aerator that runs very quiet and the 2 D cell batteries will run for a couple of days.