So i am not going to get a ho alt becuase i will not have my current car for very long, could get rid of it next week or in 6 months but not worth the money for the short time. So i just wanna add a second batt and i won't crank it to much....but what i was wondering is how do i hook it up, i heard if you arent' going to run system wiht the car off you don't need an isolator, so then how do i hook it up, just run wires from the 2 batts to each other or what???? Also is there anything cheeper than a yellow top that would work about as well????