Another dual battery question

[brichter14]

is it an option to just run a 4gauge wire from the positive terminal of the main battery (which has all of my basic boat hookups as well as my amp power) to the positive terminal of a second battery? and hook up the negative terminal of the main battery to the negative terminal of the second battery?

would this essentially double the battery life? i dont know very much about this stuff so plz help

[Wakebrad]

brichter14, yes. You just need to make sure they are exactly the same batteries. If there are any differences the batteries will constantly pull on each other and drain each other down.

You are just hooking them up in parallel by doing that - same thing as setting a perko switch to "All."

[brichter14]

would the alternator charge both while the boat is running?