I've run both 12 and 24-volt electrics on my 18' Alumaweld Stryker in lakes and the salt. Of the two systems, the 24 is superior as you get a longer run time because you don't need to use as high a thrust setting.


The higher a thrust setting, the more amps you draw from the battery. There is another reason to choose a 24-volt system, and that is that they will run quieter than a comparable 12 (and as a rule, they will last longer).


However, you shouldn't tie your cranking battery into the system because a cranking battery is not built the same way as a deep-cycle. It will fail sooner than a deep cycle because a cranking battery was not meant to be drawn down deeply before recharging.


With two honking big 12-volt deep cycle batteries, you should be able to run all day-- unless you're running at top speed.