Excuse my ignorance, please. I am in the process of upgrading my Tracker 175 to make it a little more trolling friendly. I have heard about piggybacking two twelve volt batteries to make a charge last longer. Not a 24 volt set up, but just two 12 volts working as a single 12 volt source. Can this be done, and is it something worth doing? Any drawbacks? Do the batteries have to be identical as far as amp hours or cranking amps?