I'm not getting enough run time while on the water and want to go with two batteries. I have a 12v power drive, and would like your opinions on how to run two. I have heard that connecting the two in parallel won't last as long as just having two, and switching from one to the other. So how would I go about hooking this up? I don't want to have to move terminal from one to the other, so how could I get this setup to work for me?