I use 12 volts from 2 batteries connected to a bilge pump located inside a 20 gallon storage tub to water the many flowers in my yard. I have not had a problem with the batteries that I am aware of. I checked the voltage individually on all six and they were all very close ( within .10 volts ). I think the batteries will equalize on their own. Am I all wet with this thinking? Should I buy the converter?