I am thinking about replacing the old hand pump toilet on my sail boat(cause I'm sick of the kids not being able to do it). However my experience with electric units is limited to pushing the button in wonder on friends power boats. Can any one give me any info on makes/models to look for or avoid? Obvious issues are reliabilty and current draw. Boat is a 33' 1989 GRP cruiser/racer and batteries are 2x 720cca 12v on seperate banks(can 1 battery be a bank?). Any advice would be welcome.