If you put wires between the positive and negative of a battery you short it out and that wire gets very hot indeed very fast.
I was thinking more about paralleled batteries in cars/trucks that are used a lot. In this circumstance since the batteries are probably staying pretty well charged much of the time it would probably be O.K. since the fairly well charged batteries will probably stay ballanced. In the marine examples i have seen, often boats are left for days or weeks at a time with no battery use and thus the batteries may lose charge differently and become unballanced. As for starting when cold, that could work if the individual batteries were just barely big enough to start the vehicle when at reasonable temperatures. You do double the load handling capability when you parallel batteries, and btteries are certainly less efficient and can develop less current when very cold. Tom Net-Tamer V 1.13 Beta - Registered
