the black box on the right near the air filter is a securerty 1OO amps for protecting the cable. The cable runs to the rear optima yellow top. I have a oem front battery. So that makes 2 batterys.
If that wire would be hurt the car could burst into flames. So its protected. I need the battery round volt meter to monitor the rear optima battery because i cant acces it anymore because its under the ice /trunk instal. Hope this clears things up