Originally Posted by SailBuddaMoon
You don't, not unless you have LiFePO4 batteries
An AC motor
can be run off of a 2000W inverter, but really only with the motor
running and alternator
spinning. So while it is a good back-up, it's not the recommended way to power a water maker.
Now, sure you could put a DC motor on the piston pump like the folks at Ecotec do, but in my opinion it's not really realistic to be able to handle a 40A DC load from your battery
bank without running your alternator
at the same time.
For folks that have to go 12v DC for their water maker, there really only is one choice in my mind and that is to go with a Spectra. Sure they cost a bit more, but you are paying for the design of the energy recovery pump that makes 12v DC water making possible. The piston pump used by Cruise
RO and Echotec is an energy hog pump so the best way to power that pump is with AC, but the plus is it's a simpler pump and costs less to buy and maintain.