I am adding a 2nd battery, currently engine uses a 2/0 AWG starter cable running from batttery and behind the motor to the starter on the other side. I will be adding 2nd battery and switch on same side as first battery. Do I need to try and find 2/0 AWG cables to hook all that up? I only need about 18'' from batteries to switch and its hard to find 2/0 AWG in that short of lengths.